Carbonate ramp evolution during the Late Oligocene (Chattian), Salento Peninsula, southern Italy

Palaeogeography, Palaeoclimatology, Palaeoecology 404 (2014) 109–132

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Carbonate ramp evolution during the Late Oligocene (Chattian), Salento Peninsula, southern Italy Luis Pomar a,⁎, Guillem Mateu-Vicens b, Michele Morsilli c, Marco Brandano d a

Departament de Ciencies de la Terra, Universitat de les Illes Balears, Palma de Mallorca, Spain Catedra Guillem Colom, Universitat de les Illes Balears, Palma de Mallorca, Spain Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Italy d Dipartimento di Scienze della Terra, Università di Roma “La Sapienza”, Italy b c

a r t i c l e

i n f o

Article history: Received 29 November 2013 Received in revised form 7 March 2014 Accepted 12 March 2014 Available online 21 March 2014 Keywords: Oligocene Carbonate ramp Facies analysis Corals Large benthic foraminifera Seagrass

a b s t r a c t Oligocene carbonate ramps and platforms are widespread and though they are important carbonate reservoirs, detailed studies on the facies organization, platform type and internal architecture are scarce. Within this context, the Chattian carbonate units cropping out in Salento (southern Italy) allow detailed study of the distribution of skeletal components and facies architecture. The lower Chattian Castro Limestone, previously considered as a fringing reef, is reinterpreted as a distally steepened ramp with a distal talus induced by a paleo-escarpment in the substrate. Epiphytic biota and sediment dweller organisms thriving in seagrass meadows dominated production in the shallow-water euphotic zone. Seawards, large rotalid foraminifers dominated a detritic mesophotic zone. Near the edge of the escarpment, also in the mesophotic zone, luxurious growth of corals built discrete mounds with no evidences of wave-resistant growth fabrics. Basinward, 25° to 30° dipping clinobeds abut against the escarpment where coral rudstone/floatstone textures resulted from downfall of corals and sediments. The upper Chattian Porto Badisco Calcarenite represents a homoclinal ramp dominated by packstone textures. In the euphotic inner ramp, autochthonous biota suggests the occurrence of extensive seagrass meadows. Basinward, large rotalid packstone and small coral mounds developed in mesophotic conditions, and rhodolithic floatstone to rudstone and large lepidocyclinid packstone characterize the sediments of the deeper oligophotic zone. Comminuted skeletal debris, depleted of light-dependent organisms, typifies deposition in the dysphotic/aphotic zone. In both examples, the middle ramp (meso-oligophotic zones) was the most prolific in terms of carbonate production, whereas shallow-water seagrass-related production (euphotic) was much less important. Corals built mounds, also in the mesophotic zone but never reached sea level. Hydrodynamic conditions in the meso-oligophotic zone are better explained by breaking of internal waves, and their induced up- and down-slope currents, instead of the surface storm waves. © 2014 Elsevier B.V. All rights reserved.

1. Introduction The Oligocene was a transitional period characterized by significant changes in the carbonate-producing biotas, and in the architecture of coral buildups and carbonate platforms (Perrin, 2002). Following the warm Eocene, with carbonate production dominated by larger benthic foraminifera (LBF), a stepwise global cooling gave way to a period with extensive coral buildup development. Oligocene reefs represent the apex of Cenozoic reef growth, particularly recognized in the Caribbean and Mediterranean paleo-biogeographic provinces (Frost, 1977a, 1997b; Bosellini and Russo, 1992). Subsequently, the latest Oligocene through Early Miocene warming coincides with still active production by LBF, though not as prolific as during the Eocene (e.g., Chaproniere, 1984; Betzler, 1997; Hallock et al., 2006). Coralline red algae increased ⁎ Corresponding author. Tel.: +34 971 173 160; fax: +34 971 173 184. E-mail address: [email protected] (L. Pomar).

http://dx.doi.org/10.1016/j.palaeo.2014.03.023 0031-0182/© 2014 Elsevier B.V. All rights reserved.

in diversity during the Oligocene (e.g., Manker and Carter, 1987; Buxton and Pedley, 1989; Pedley, 1998; Aguirre et al., 2000; Rasser and Piller, 2004) and globally became dominant carbonate producers during Early and Middle Miocene times (Halfar and Mutti, 2005). Their peak in red-algae abundance paralleled the increased extinction rates of planktonic foraminifers, radiolarians, corals and LBF (Halfar and Mutti, 2005). Diversification of the large Nummulites and other Paleogene LBF occurred when the deep sea was warmer, being the apex of these groups when there was minimal temperature gradient between the thermocline and the deep sea (Hallock and Pomar, 2009). During the Oligocene–Miocene, the biogeography of reef corals was gradually changing from the Tethyan Province in the Eocene to three reef-coral Provinces: the Western Atlantic–Caribbean, the Indo-Pacific and the Mediterranean (Perrin and Bosellini, 2012). During the Cenozoic, the latitudinal contraction/expansion of the reef belt broadly follows global temperature; the width of this belt shrank near the Eocene–Oligocene cooling event and widened again during the Chattian, with its widest

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extension occurring during the warm Middle Miocene (Perrin and Kiessling, 2012). Pochon et al. (2006) suggested that Symbiodinium, the symbiont harbored by corals, originated during the Early Eocene and divergence took place during periods of global cooling. These authors remark that none of these extant symbionts, except those harbored by soritid foraminifera, diverged during the period between Late Oligocene warming and mid-Miocene climatic optimum. It seems that whereas global cooling favors coral diversity, warming favors latitudinal expansion of coral reefs. Oligo-Miocene carbonates are extensive throughout the world. Outcrop studies are abundant, particularly in the Mediterranean region (see Perrin and Bosellini, 2012 and references therein). Other Oligo-Miocene platforms and ramps are good hydrocarbon reservoir, e.g., Malampaya, Philippines (Grötsch and Mercadier, 1999; Fournier and Borgomano, 2007), Iran (van Buchem et al., 2010), offshore Venezuela (Borromeo et al., 2011; Pinto et al., 2011), eastern Borneo (Noad, 2001), central Kalimantan, Indonesia (Saller and Vijaya, 2002), the Zhujiang Formation, China (Lomando et al., 1995; Sattler et al., 2009). Nevertheless, detailed studies about the structure of the coral buildups are scarce and most of them use the modern Caribbean barrier-reef shelf-lagoon complex model for interpretation (e.g.: Frost, 1981; Bosellini and Perrin, 1994; Bosellini, 2006). The concept of the tropical carbonate factory is commonly associated with the carbonate production that occurs in warm, well-illuminated, oligotrophic, near-surface waters of the tropics and subtropics, in which corals are important reef builders and form a rigid, wave resistant framework up to sea level (Hallock and Schlager, 1986; Schlager, 2000, 2003; Hallock, 2005; Schlager and Purkis, 2013). Nevertheless, the number of outcrop studies identifying facies associations, depositional geometries, and stratigraphic architectures different from the standard modern Caribbean model are scarce, although increasing (Nebelsick et al., 2000; Brandano et al., 2009a, 2009b; Bassi and Nebelsick, 2010) and the importance of the oligophotic carbonate production (mostly by LBF and red algae) in tropical–subtropical conditions is progressively better recognized. Nebelsick et al. (2000) reported Lower Oligocene carbonates in Slovenia to conform a ramp system in which main components are red algae and foraminifers, but corals are scarce. Corals occur scattered through the entire depositional profile but preferentially form thickets in the deeper part of the photic zone. Lower Oligocene carbonates in Austria are also dominated by red algae and foraminifers, while coral colonies are scarce, although present as small fragments in the matrix; they mostly occur as isolated colonies in mud-rich sediments (Nebelsick et al., 2001). In the Attard member of the Lower Coralline Limestone Formation (Upper Oligocene, Malta), Brandano et al. (2009a) recognized four main facies: high-energy shallow-water deposits of the inner ramp pass, downslope, into seagrass epiphytic-dominated sediments that, in turn, interfinger basinward with sediments containing scattered corals. Middle-ramp facies are dominated by red algae and LBF but contain small coral patch-reefs with poorly developed framework textures. The biotic associations and paleo-latitudinal reconstructions suggest that carbonate production took place in tropical waters under oligotrophic conditions (Brandano et al., 2009b). These authors emphasized this Late Oligocene ramp to have many affinities with Lower–Middle Miocene ramps: expansion of the seagrass into the euphotic zone, reduction and changes in LBF production, increase of red algal production in middle-ramp settings, and occurrence of corals in small patches without framework textures. In the Lessini Shelf and in the Venetian foreland basin (Southern Alps), Bassi and Nebelsick (2010) have also documented an Upper Oligocene gently-dipping homoclinal ramp, in which most benthic carbonate production occurred in distal-inner- to proximal-middle ramp settings, with trophic gradients constrained by fluvial influence. Main producers were larger benthic foraminifera and red algae but zooxanthellate corals are missing and dasycladacean green algae are very rare (Bassi and Nebelsick, 2010).

Within this context of evolving conceptual depositional models, the aim of this paper is to document in detail the changing character of facies and depositional architecture of two stratigraphic units: the lower Chattian Castro Limestone and the upper Chattian Porto Badisco Calcarenite, cropping out in the Salento Peninsula, southern Italy. These changes respond to a swap of carbonate producers. Corals dominated and red algae were subordinated in the lower Chattian Castro Limestone, while larger benthic foraminifera and red algae dominated production, and corals became subordinated in the upper Chattian Porto Badisco Calcarenite. The analysis here presented is based on the study of the spatial distribution of facies and skeletal components and their paleoecological significance, avoiding the use of the modern coral-dominated Caribbean type platform model. 2. Geological setting and previous work The Apulia Carbonate Platform (ACP), one of the peri-Adriatic carbonate banks that developed at the southern margin of the Tethys Ocean, is the foreland of both the Apennine and the Dinaric thrust and fold belts (Bernoulli, 2001) (Fig. 1A, B). This platform, almost exclusively composed of shallow-marine carbonates of Late Triassic to Late Cretaceous age (Bosellini and Parente, 1994). Similarly to the adjacent Apennine platforms (Latium-Abruzzi- and Campano-Lucana Platforms), the Paleogene shallow-water carbonates occurred along the platform margins (Bosellini and Parente, 1994; Parente, 1994; Bosellini et al., 1999; Bosellini, 2006). On the eastern coast of the Salento Peninsula, the platform margin of the ACP is visible. Here, Eocene, Oligocene and Miocene carbonate units are exposed on top of the 4200 m-thick Cretaceous succession (Bosellini and Russo, 1992), mostly accommodated and preserved in scallops and embayments of the Cretaceous platform (Bosellini et al., 1999). In the Salento Peninsula, Largaiolli et al. (1966) and Nardin and Rossi (1966) first distinguished a reef limestone from a bioclastic limestone within the Oligocene rocks. Later, Rossi (1969) defined these two stratigraphic units as the Castro Limestone (Eocene–Oligocene) and the Porto Badisco Calcarenite (Upper Oligocene). Bosellini and Russo (1992) interpreted the Castro Limestone and the Porto Badisco Calcarenite as two unconformity-bound depositional sequences. The Castro Limestone disconformably overlies slightly deformed Cretaceous platforms and discontinuous Eocene carbonate deposits, and it is unconformably overlain by a distinctive rhodolith horizon at the base of the Porto Badisco Calcarenite. The 5 to 30 cm thick, phosphate–glauconite-rich Middle Miocene “Aturia level” (Bosellini and Russo, 1992; Parente, 1994) unconformably overlies the Porto Badisco Calcarenite. Based on the foraminiferal associations, Bosellini and Russo (1992) and Parente (1994) established a more precise age control of these Upper Oligocene stratigraphic units. The occurrence of Lepidocyclina (Eulepidina) dilatata, the highly evolved form of Lepidocyclina (Nephrolepidina) praemarginata, and the absence of Miogypsinidae indicate the Castro Limestone to belong to the middle Chattian, and particularly to the “Spiroclypeus droogeri–C. mediterraneus” zone of Drooger and Laagland (1986), corresponding to the SBZ 22B of Cahuzac and Poignant (1997). The presence of Lepidocyclina (Eulepidina) dilatata, Lepidocyclina (Nephrolepidina) morgani, Miogypsina (Miogypsinoides) ex. interc. complanata-formosensis, Neorotalia viennoti, Operculina complanata, Heterostegina assilinoides, Amphistegina sp., and Austrotrillina sp. allowed Parente (1994) to assign the Porto Badisco Calcarenite to the late Chattian Miogypsinoides zone of Drooger and Laagland (1986), corresponding to the SBZ 23 of Cahuzac and Poignant (1997). The Castro Limestone consists of coral-bearing limestones that unconformably cover Cretaceous-Eocene limestone rocks; a high diversity and abundant coral fauna with a moderate presence of coralline algae characterize the Castro Limestone. It has limited thickness on top of the ACP and abuts, with limited progradation, against a paleo-escarpment on the margin of the ACP (Bosellini et al., 1999). This configuration

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Fig. 1. (A) The Apulian Foreland in southern Italy (modified from Pieri et al., 1997). (B) The three structural highs of the Apulian Foreland: Gargano, Murge and Salento (modified from Pieri et al., 1997). (C) Location of the study areas in the Salento. (D) Location of the studied outcrops near Castro; SC: Santa Cesarea, Pm: Portomiggiano, LS: La Scogliera, Rm: Romanelli cave, Zz: Zinzulusa cave, Vt: Vitigliano. (E) Studied and sampled locations in the Porto Badisco Calcarenite; S1 to S6: logged and sampled sections, FC1 and FC2: sampled localities.

confers to the Castro Limestone lithosome a sigmoid-like shape. Mostly based on this sigmoid-like shape and using the standard Modern Caribbean barrier-reef shelf-lagoon model, Bosellini and Russo (1992) and Bosellini and Perrin (1994) interpreted the Castro Limestone as a fringing reef complex, and distinguished four reef environments: back reef, reef flat, reef front and fore reef. The associated facies were characterized according to the position of the outcrops within the Castro Limestone lithosome, the distribution and attributes of the coral fauna and on the bedding patterns. These authors emphasized, however, that a real back-reef lagoon is lacking. The Porto Badisco Calcarenite consists of up-to 50–60 m thick, poorly cemented bioclastic, horizontally bedded calcarenites, which appears to infill a paleo-depression in the area of Porto Badisco (Bosellini et al., 1999). Brandano et al. (2010) concentrated in the study of rhodoliths in this rhodalgal-larger benthic foraminifera dominated unit in which, up to the present, no corals or coral buildups were recognized, although these authors consider the biota characteristic of tropical conditions. The dominance of melobesioids and sporolithaceans with respect to mastophoroids in the rhodoliths, and the larger benthic foraminifera assemblages associated with the rhodoliths, led Brandano et al. (2010) to conclude that it was a significant sediment accumulation in the oligophotic zone, as result of both in-situ production and resedimentation of foraminifers from shallowwater settings. Formalized as the Galatone Formation, Esu et al. (1994), Bossio et al. (1998) and Margiotta and Ricchetti (2002) described a continental and brackish-water succession, which represents the continental-to-marine transition of the Upper Oligocene deposits in the Salento Peninsula, although a physical correlation with the Castro Limestone or the Porto

Badisco Calcarenite, cannot been achieved (Bosellini et al., 1999). This stratigraphic unit is not considered in our study. 3. Methods Exposures on sea-cliffs, road-cuts and natural outcrops allowed the analysis of lithofacies, bedding geometries and facies architecture of the Castro Limestone. The Porto Badisco Calcarenite was investigated on the margins of a ravine parallel to the depositional dip direction, allowing facies characterization from the shallow-water inner belt to the deeper-water outer belt. At Porto Badisco, six logged sections have been used for sampling control and a key bed has been walked along dip direction for log correlation. Stratigraphic and sedimentological interpretations are based on mapping on outcrop photographs where samples have been located. Field observations were complemented with the study of over 100 thin sections for textural characterization and identification of skeletal components. Abundance of components has been estimated qualitatively in five categories: very rare (b 5%), rare (5%–10%), frequent (10%–25%), abundant (25%–50%) and very abundant (N 50%). 4. The Castro Limestone The Castro Limestone has been investigated in outcrops occurring in road-cuts and sea-cliffs between Castro, Vitigliano and Santa Cesarea villages (Fig. 1D). The most outstanding carbonate producers were corals and larger benthic foraminifera (LBF), whereas red algae, although present, were subordinated. Among corals, Bosellini and Russo (1992) recognized Astrocoenia, Astreopora, Pavona, Siderastrea,

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Table 1 Lithofacies, components and interpretation of the Castro Limestone. Lithofacies

Components

Locality LSa La Scogliera (East) Well-stratified landward-dipping coral rudstone with poorly-sorted packstone-to-wackestone matrix. Apparent grainstone texture by dissolution of muddy matrix

La Scogliera Foraminifers Abundant porcellaneous: small miliolids, symbiont bearing (Sorites, Peneroplis, Austrotrillina). Abundant large rotalids: broken and intact nummulitids (Heterostegina, Operculina, Spiroclypeus), reworked Neorotalia, Nephrolepidina fragments, well-preserved Amphistegina. Frequent small perforate forms (Lobatula, Planorbulina, discorbids–rosalinids) Rare encrusting victoriellids (including Carpenteria) and acervulinids Some planktonics Red algae Nodules and crusts of non-articulated forms including mastophoroid Spongites. Rare fragments of articulated forms Other minor components Very rare fragments of bryozoans, decapods, bivalves (including pectinids) and echinoderms.

Interpretation

LSb La Scogliera (West) Crudely-stratified packstone with large rotalids Passing landward into Epiphytic-dominated wackestones to packstones with scattered coral colonies

Foraminifers Abundant Neorotalia. Frequent broken and intact nummulitids (Heterostegina, Operculina, Spiroclypeus). Frequent fragments of Nephrolepidina. Frequent well-preserved, thick Amphistegina. Frequent symbiont-bearing porcellaneous (Sorites, Peneroplis, Austrotrillina). Frequent small epiphytic rotalids (Lobatula, Planorbulina, discorbids–rosalinids). Rare planktonics Red algae Rare articulated-algae fragments. Components are qualitatively the same as those described in the facies immediately above, but the proportions change, and mud content increases. Foraminifers Abundant epiphytic rotalids (Lobatula, Planorbulina, discorbids–rosalinids). Abundant porcellaneous taxa (small and symbiontbearing forms). Frequent large rotalids. Red algae Frequent hooked, non-articulated forms.

Locality SC-L: lower interval Coral floatstone and gastropod-bivalve floatstone, with a grainstone matrix Molds and intraskeletal pores infilled by fine-grained wackestones to packstones with few planktonic and small benthonic foraminifers

Santa Cesarea Foraminifers Abundant large rotalids (Nephrolepidina fragments, nummulitids, fragments and intact Neorotalia, intact thick Amphistegina). Frequent fragments of symbiont-bearing porcellaneous Austrotrillina. Frequent small miliolids. Very rare encrusting forms (Sphaerogypsina). Coral colonies (some in living position). Red algae Rhodoliths. Abundant nodules and crust fragments (some hooked forms). Rare non-articulated fragments.

SC-M: middle interval Well-cemented coarse grainstone, with trough cross-stratification. Coral colonies on the flanks of the “channel-like” structures

Components are very similar to those of the lower interval (SC-L)

The middle interval represents a high-energy zone where the coarse skeletal grains were channelized between coral mounds.

SC-U: upper interval Large in-situ coral colonies in a coarse-grainstone matrix

Corals: very abundant (Bosellini and Russo, 1992) Laminar poritids (Porites, Goniopora, Actinacis). Massive faviids (Leptoria, Hydnophora, Thegioastraea, rare Favites, Favia, Tarbellastraea, Montastrea). Rare Astreopora, Alveopora, Caulastrea. Foraminifers Porcellaneous taxa (small miliolids, symbiont-bearing Austrotrillina and Peneroplis).

The upper interval was deposited in a high-energy zone, populated by abundant corals, (cluster reef, sensu Riding, 2002). Sediments produced in the seagrass meadows were transferred basinward. Indicators are the abundant small epiphytic forms (discorbids–rosalinids, Lobatula and encrusting Planorbulina) and large porcellaneous (Peneroplis, Austrotrillina).

Low-energy environment, below the wave-base level hit with episodic high-energy events. The mixture of large rotalids along with the seagrassassociated bioclasts (porcellaneous forms and small rotalids) indicates meso-euphotic conditions.

Large-rotalid-dominated packstones (in situ nummulitids, Neorotalia, Nephrolepidina) are indicative of mesophotic settings where sparse seagrass thrived. Landwards, mud content and epiphytic components increase, along with symbiont-bearing porcellaneous taxa. In contrast, large rotalids became scarcer. In this environment, at shallower depths, extensive meadows occurred. Seagrass meadow interpretation is also supported by the presence of red-algae crusts with growth forms adapted to the contour line of the seagrass leaf (hooked forms sensu Beavington-Penney et al., 2004) and the increase in limemud in the matrix due to the baffling and trapping effects by the seagrasses. The shallowing-landward trend is confirmed by the abundance of well-preserved, thick specimens of Amphistegina, well-adapted to euphotic conditions. Notwithstanding, the occurrence of other large rotalids (Nephrolepidina, Neorotalia) reflects mesophotic conditions below the dense leaf-canopy.

For the lower interval, the abundance of large coral fragments and the mixture of skeletal components transported from the shallow seagrass meadows and elements incorporated from the mesophotic factory (large rotalids, red algae crusts and nodules), suggest deposition at the front of a high-energy cluster reef. High-energy conditions prevented deposition of muddy textures, except within the intraskeletal pores of the coral colonies.

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Table 1 (continued) Lithofacies

Components

Interpretation

Textulariids Symbiont-bearing porcellaneous become rare upwards, while small miliolids and textulariids dominate throughout the section. Rare large rotalids (fragments of nummulitids and Nephrolepidina, more-or-less reworked Neorotalia, Amphistegina). Frequent epiphytic forms (Planorbulina, Lobatula, discorbids–rosalinids). Encrusting victoriellids, homotrematids, acervulinids and agglutinated forms (Haddonia). Red algae Very abundant crust fragments (some hooked forms). Rare fragments of articulated taxa. Echinoderms Very abundant fragments). Other minor components Fragments of serpulids, gastropods, bryozoans, brachiopods, decapods.

The occurrence of red algae crusts with hooked forms can also be related to transport from seagrass meadows. Articulated red algae have been produced at shallow depths.

Locality

Castro Clinobeds (Zinzulusa Cave, Romanelli Cave, Portomiggiano)

TA Coral rudstone with mud-rich, wackestone to packstone matrix.)

Corals Scattered and overturned dm-sized colonies, encrusted by red algae and foraminifers. Foraminifers Abundant planktonic forms. Small benthic taxa are frequent and include epiphytic taxa (i.e. cibicidids, discorbids–rosalinids, small miliolids, Planorbulina), textulariids (i.e. Bigenerina), bolivinids and Lenticulina. Large rotalids include fragments of Nephrolepidina, reworked Neorotalia and preserved Amphistegina. Symbiont-bearing porcellaneous are rare reworked (Austrotrillina, Peneroplis and very rare Borelis). Encrusting acervulinids, victoriellids and Haddonia. Red algae Fragments and crusts of non-articulated algae. Rare articulated red algae and Subterraniphyllum. Other minor components Cortoids, Echinoids, bryozoans, bivalves, brachiopods.

Lithofacies TA deposited during periods of high sea level, when the shallow-water carbonate factory (seagrass) and the mesophotic large-rotalids factory occurred landwards of the edge, onto the flat top of the of the Apulian Carbonate Platform. In this context, the coral buildups at the edge of the ACP did not develop and the shallow meso- and euphotic factories where away from the margin of the ACP. Coral fragments might have been derived from erosion of pre-existing coral colonies near the edge of the ACP. The muddy matrix is indicative of accumulation below the wave base level, but coral breccia was sourced at the edge of the ACP. The alternation of facies TA and TB reflects sea-level cyclicity.

TB Coral rudstones with large and overturned coral colonies in a very-coarse grainstone matrix

Corals (Bosellini and Russo, 1992) Abundant colonies and fragments of meandroid corals (Hydnophora, Leptoria, Diploria). Large colonies of Astreopora, Thegioastraea and Favia, poritids. Foraminifers Abundant large rotalids (reworked Neorotalia and Nephrolepidina, well-preserved thick and flat Amphistegina). Frequent small benthic forms (many of them epiphytic: discorbids–rosalinids, Planorbulina, Sphaerogypsina, cibicidids, miliolids). Frequent symbiont-bearing porcellaneous taxa (Austrotrillina, Peneroplis, rare Sorites and very frequent Borelis). Rare encrusting forms (acervulinids, victoriellids and Haddonia) Red algae Abundant fragments and encrusting coral fragments. Rare articulated algae and Subterraniphyllum Other minor components Fragments of bryozoans, bivalves, decapods, ostracods.

Lithofacies TB deposited during periods of low sea level, with higher hydrodynamic conditions at the edge of the ACP. These high-energy events triggered the downfall of large coral colonies and sediments from the edge (coral-falls and debrites) The proximity of the euphotic (seagrass) and mesophotic (large rotalids) to the margin, favored the basinward transport and mixture of very shallow-water bioclasts with others from the mesophotic zone (i.e. large rotalids and red algae). The absence of mud also suggests high energy in the deposition loci on the talus. The alternation of facies TA and TB reflects sea-level cyclicity.

Goniopora, Porites, Actinacis, Alveopora, Favia, Montastrea, Caulastrea and Tarbellastraea. Two main groups of facies occur within the Castro Limestone. West-northwest of the paleo-escarpment, the Castro Limestone lies horizontally with limited thickness (top beds) onto the Cretaceous and Eocene limestones of the ACP (Fig. 1D). East-southeast of the paleo-escarpment (Fig. 1D), the Castro Limestone consists of clinobeds abutting the southeast-facing paleo-escarpment of the ACP. The roadcut outcrop near Vitigliano (Vt; Fig. 1D), previously interpreted as back-reef deposits within the Castro Limestone (Bosellini and Perrin,

1994), has to be placed within the Porto Badisco Calcarenite due to the presence of Miogypsinoides. Lithofacies characteristics and interpretation are summarized in Table 1. 4.1. The Castro Limestone top beds 4.1.1. La Scogliera east (LSa) La Scogliera east (LSa) is situated at the eastern margin of the outcrop, just near the paleo-escarpment (Fig. 1D). Well-stratified coral

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grainstone texture results from diagenetic dissolution of the muddy matrix (Fig. 2C). At the base of these beds, a thin coral breccia layer may occur. Among foraminifers, porcellaneous taxa are the most conspicuous, including both small forms (i.e. miliolids) and symbiont-bearing forms (Sorites, Peneroplis, Austrotrillina) (Fig. 2C). Large rotalids are abundant and are represented by a mixture of broken and well-preserved tests of nummulitids (Heterostegina, Operculina, Spiroclypeus), reworked Neorotalia and fragments of Nephrolepidina (Fig. 2B). Thick, well-preserved Amphistegina tests, small perforate forms (Lobatula, Planorbulina, discorbids–rosalinids) and some planktonic foraminifera also occur. Encrusting forms such as Carpenteria, other victoriellids and acervulinids are present. Red algae mostly correspond to fragments of crusts and nodules of non-articulated taxa (including mastophoroid Spongites). Rare fragments of articulated forms also occur. Other components are fragments of bryozoans, decapods, bivalves (including few pectinid fragments) and echinoderms. Interpretation — These characteristics indicate this facies to have been deposited in a low-energy environment, below wave base, but hit by episodic high-energy events, as suggested by the abundant coral breccia, and situated in a back position of a coral mound1 as suggested by the depositional geometries (Fig. 2A). The coral mound, however, has been removed by present erosion. Some foraminifers suggest mesophotic conditions (nummulitids, Neorotalia, Nephrolepidina, etc.). This bathymetric scenario (Fig. 3) is confirmed by the occurrence of mastophoroid redalgal crusts and articulated red-algae fragments (Aguirre et al., 2000). Nevertheless, this facies also contains seagrass-related bioclasts. It may be explained by the presence of sparse clumps of grasses on top of the coral mound, placing the site in meso-euphotic conditions (Fig. 4) at a relatively shallow depth, but below the base of wave action.

Fig. 2. La Scogliera East (LSa). (A) Field view of La Scogliera east outcrop, with wellstratified coral rudstone with poorly sorted packstone–wackestone matrix, interpreted to have been deposited in a back position of a coral mound. (B) Poorly sorted packstone with abundant foraminifers and red-algal fragments. (C) Apparent grainstone, resulting from muddy matrix dissolution, with abundant porcellaneous foraminifers. Cor: coral fragment, Bry: Bryozoan, RA: non-articulated red algae, AA: articulated red algae. Foraminifers: Amp: Amphistegina, Aus: Austrotrillina, Mil: Miliolids, Glo: Globigerinid, Pen: Peneroplis, Pyr: Pyrgo, Rot: Neorotalia, Sor: Soritid, Spir: Spiroclypeus, Spo: Sporadotrema.

rudstone with poorly sorted packstone–wackestone matrix occurs in few-meter-thick beds bounded by erosion surfaces (Fig. 2A). Most coral colonies, with both massive and branching forms, are in living position although some are broken and overturned. The depositional dip of these beds is around 10° towards the landward side. Between the corals, the matrix consists of poorly sorted packstone dominated by foraminifers and red algae fragments (Fig. 2B). Locally, an apparent

4.1.2. La Scogliera west (LSb) Towards the west (landwards) (Fig. 1D), on a road-cut, around two meter high, the back-mound facies pass into crudely stratified packstone with large rotalids and then into pack-wackestone with abundant epiphytic components, with scattered coral colonies. Bedding is very obscure and only identified by subtle changes in the rock texture and the alignment of some coral colonies. The landward increase of limemud content in the matrix parallels a decrease of the grain size of the bioclasts and of the coral colonies. The large-rotalid packstone (Fig. 5A) is characterized by abundant Neorotalia. It also contains a mixture of broken and well-preserved tests of nummulitids (Heterostegina, Operculina, Spiroclypeus), fragments of Nephrolepidina and thick, well-preserved Amphistegina tests, symbiontbearing porcellaneous foraminifers (Sorites, Peneroplis, Austrotrillina), small epiphytic forms (Lobatula, Planorbulina, discorbids–rosalinids), and planktonic foraminifers. In this facies, in-situ nummulitids, Neorotalia and Nephrolepidina indicating mesophotic conditions (Hohenegger, 2005; Hallock and Pomar, 2009) in which some sparse seagrass mattes might have thrived, are mixed with allochthonous bioclasts (large porcellaneous foraminifers, thick Amphistegina, articulated red algae and some small epiphytes) transported from inner settings. Landwards, the wackestones to packstones contain, qualitatively, the same components as those mentioned above, but the proportions change; towards the west (landwards) there is a decrease of large rotalids and an increase of epiphytic forms (Fig. 5B), and hooked forms of non-articulated red-algal crusts become common (Fig. 5C). This trend also parallels an increase of limemud content. In the innermost part of the outcrop, the abundance of Lobatula and Planorbulina, discorbids–rosalinids and small miliolids, along with large porcellaneous taxa, indicates the occurrence of extensive seagrass meadows 1 Reef mound: a biologically-influenced buildup lacking the remains of prominent frame-building organisms. These frame-lacking reefs have been termed reef mounds (James, 1983), and were not generally capable of forming reef complexes with waveresistant reef fronts and crests (Tucker and Wright, 1990; page 221).

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Fig. 3. Relative proportion (thin-section estimations) of in-situ skeletal components at La Scogliera. LSa: La Scogliera east; LSb: La Scogliera west.

Fig. 4. Bathymetric light zones based on the proportion of surface light with depth for different extinction coefficients of light (modified from Morsilli et al., 2012). The subdivision in euphotic, oligophotic, and sometimes an intermediate mesophotic zones, permits to establish a general, non-quantitative, depth-dependent light-penetration zonation of the carbonate production. The bathymetry of the lower limit of these zones depends on water transparency, being deeper in blue (oligotrophic) waters and shallower in green (eutrophic) waters. The lower limit of these zones also varies with latitude (irradiance at sea surface), being shallower in high latitudes and deeper in low latitudes. Curves of light penetration for different extinction coefficients of light are based on Kanwisher and Wainwright (1967), Huston (1985), Hallock and Schlager (1986) and Kahng et al. (2010).

(Fig. 3) in euphotic conditions (Fig. 4). These forms are included within the different epiphytic morphotypes that characterize the seagrass ecosystem (Langer, 1993; Ribes et al., 2000; Mateu-Vicens et al., 2010; Frezza et al., 2011). Epiphytic foraminifers have their life span adapted to the seagrass leaf seasonal renewal, especially in the case of longliving, sessile, encrusting forms (A morphotype) and symbiontbearing porcellaneous taxa (reported as primary weed-dwellers; Brasier, 1975). These foraminiferal taxa have also been used to infer the occurrence of seagrass meadows in other localities (e.g., Upper Miocene in Menorca, Spain: Mateu-Vicens et al., 2008a; Pliocene in Matera, southern Italy: Mateu-Vicens et al., 2008b; southern Kerala, India: Reuter et al., 2011). Heterometric packstone to wackestone textures are also in agreement with the occurrence of seagrass meadows, whose blades baffle the hydrodynamic energy and contribute to settling and trapping of fines within the rhizomatic mesh (Davies, 1970; Scoffin, 1970; Brasier, 1975; Pomar et al., 2002; Beavington-Penney et al., 2004). Interpretation — Thick specimens of Amphistegina are associated to shallow-water, well-illuminated conditions (Hallock, 1984, 1999; Mateu-Vicens et al., 2009), and they are frequently reported in seagrass meadows (Blanc-Vernet, 1969; Sen Gupta, 1999; Reuter et al., 2011). Articulated red algae are also indicative of shallow-water conditions (Wray, 1977; Nishimura, 1992). In contrast, the abundance of nonarticulated red algae is often associated to meso-oligophotic conditions (Fig. 4) that, in seagrass meadows, occur below the dense blade canopy. Some of the non-articulated red algae appear as hooked crusts that reflect a growth pattern adapted to the leaf structure, which confirms the occurrence of seagrass meadows (Beavington-Penney et al., 2004). Similarly, the mesophotic large symbiont-bearing rotalids such as Neorotalia and Nephrolepidina (Brandano et al., 2009a, 2009b) may have thrived in the shade of the seagrass blades (Reuter et al., 2011). 4.2. Santa Cesarea (SC) This outcrop is situated northwest of Santa Cesarea Terme, on the road to Poggiardo (Fig. 1C, D). Here, the Castro Limestone sits

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Fig. 5. La Scogliera west (LSb). (A) Large-rotalid packstone with partly corroded fine matrix. (B) Packstone to wackestone with abundant epiphytic forms. (C) Detail of a hooked non-articulated red algal fragment (HRA) indicative of the occurrence of seagrasses corresponding to the packstone-to-wackestone microfacies with abundant epiphytic foraminifers. Ech: echinoderm fragment, Biv: bivalve fragment, RA: non-articulated red algae. Foraminifers: Rot: Neorotalia, Spi: Spiroclypeus, Amp: Amphistegina, Bol: Bolivina, Dis: Discorbid, Lob: Lobatula, Nep: Nephrolepidina, Spo: Sporadotrema.

unconformably on Middle Eocene limestone with Alveolina (Bosellini and Russo, 1992). This outcrop occurs in a roadcut and extends roughly in depositional-strike direction, parallel to the paleo-escarpment. Although bedding is obscure and irregular, three main intervals can be distinguished in a less than 20-m thick succession. The lower interval mostly consists of coral floatstone with a grainstone matrix. The middle interval is dominated by channelized coarse grainstone. In the upper

interval, large coral colonies are abundant and occur in living position, embedded in coarse grainstone matrix. The lower interval (SC-L), although bedding planes are not visible, mostly consists of coral floatstone and interbedded bivalve-gastropod floatstone with well-cemented grainstone to packstone matrix (Fig. 6A). The basal coral floatstone contains rhodoliths. Locally, some coral colonies appear in living position. The most conspicuous components in the grainstone to packstone matrix (Fig. 6B) are large foraminifers, including rotalids such as fragments of Nephrolepidina, nummulitids, Neorotalia (whole and fragments), and intact and thick Amphistegina tests. Large porcellaneous taxa are scarcer and correspond to reworked Austrotrillina. Foraminifers other than large forms are not abundant and mostly consist of small miliolids, and very rare encrusting forms (i.e. Sphaerogypsina). Fragments of red-algae nodules and crusts are also abundant, although non-articulated red algae fragments are scarce. Fragment of bivalves and gastropods occur as molds and intraskeletal pores in corals are often filled by fine-grained wackestone to packstone with few planktonic- and small benthonic foraminifers. In the thin layer with corals in living position, the limemud content in the matrix increases, as well as the fragments of red-algae crusts (with hooked forms). The middle interval (SC-M) consists of well-cemented coarse grainstone with trough cross-stratification (Fig. 6C); locally, coral colonies in living position occur on the flanks of these furrows. The skeletal composition in the matrix is similar to the lower interval, dominated by larger benthic foraminifera (Fig. 6D). The upper interval (SC-U) contains abundant and large in-situ coral colonies in a coarse grainstone matrix (Fig. 6E). Bosellini and Russo (1992) recognized hemispherical and laminar poritids (Porites, Goniopora and Actinacis) and massive faviids (Leptoria, Hydnophora and Thegioastraea; rare Favites, Favia, Tarbellastraea and Montastrea), and Astreopora, small Alveopora and Caulastrea locally occur. Although Bosellini and Russo (1992) interpreted a reef-front with a “dense-rigid framework with massive coral colonies in point-to-point contact” (Bosellini and Russo, 1992; page 156), coral intergrowth is not evident. In this outcrop there is absence of primary cavities. Consequently, a wave-resistant organic structure cannot be interpreted as it would be in a sensu stricto framework (e.g., Lowenstam, 1950; Scoffin, 1972; Insalaco, 1998). The domestone growth fabric (sensu Insalaco, 1998) characteristic of the upper interval fits better with the segment or cluster2 reef (sensu Riding, 2002). Dominant matrix support in cluster and segment reefs precludes development of substantial relief relative to lateral extent (Riding, 2002). Through the entire upper interval, the matrix is very similar in terms of composition and textures. It consists of coarse grainstones with very abundant fragments of red-algal crusts (often with hooked forms), foraminifers and echinoderms (Fig. 6F). Serpulid, gastropod, bryozoan and articulated red-algae fragments are scarce. Brachiopod and decapod fragments are very rare. Large coral fragments are frequent, commonly encrusted by red algae and foraminifers, and the intraskeletal pores are infilled by fine-grained wackestone to packstone. Among foraminifers, the most conspicuous are porcellaneous taxa, including both small miliolids and symbiont-bearing genera (Austrotrillina and Peneroplis) and textulariids. Large porcellaneous foraminifers become very scarce on top of the interval, while small miliolids and textulariids dominate along the whole section. Large rotalids are scarce and occur as fragments of nummulitids and Nephrolepidina and reworked Neorotalia, and rare Amphistegina. Small benthic forms are common, including epiphytic Planorbulina, Lobatula and few discorbids–rosalinids. Coral-

2 From Riding (2002): Cluster reefs: are skeletal reefs in which essentially in place skeletons are adjacent, but not in contact, resulting in matrix support; characterized by relatively high matrix/skeleton ratios and low volumes of extra-skeletal early cement. Segment reefs: are matrix-supported reefs in which skeletons are adjacent, and may be in contact, but are mostly disarticulated and mainly parautochthonous. Matrix abundance is high, and early cement relatively low.

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Fig. 6. Santa Cesarea. A: Lower-interval lithofacies consists of coral-floatstone and interbedded bivalve-gastropod floatstone with grainstone matrix, unconformably overlying Eocene limestone (Arrow marks the unconformity). Scale is 10 cm. B: Lower interval (SC-L) microfacies consists of well-cemented grainstone to packstone with abundant foraminifers. C: Trough cross-stratification of the middle interval. D: Middle interval (SC-M) microfacies consists of well-cemented coarse grainstone with abundant large benthic foraminifers. E. In-situ coral colony of the upper interval. Scale is 10 cm. F: Upper interval (SC-U) microfacies consists of a coarse grainstone with fragments of non-articulated red-algal crusts, echinoids and foraminifers. Ech: Echinoderm fragment, Biv: Bivalve fragment, Bry: Bryozoan fragment, Cor: Coral fragment, RA: Non-articulated red algae, AA: Articulated red algal fragment. Foraminifers: Amp: Amphistegina, Aus: Austrotrillina, Cib: Cibicidid, Lob: Lobatula, Mil: Miliolid, Nep: Nephrolepidina, Num: Nummulitid, Pen: Peneroplis, Pyr: Pyrgo, Rot: Neorotalia, Sor: Soritid.

encrusting foraminifers are victoriellids, homotrematids, acervulinids and agglutinated forms such as Haddonia. Interpretation — Based on the skeletal composition and textures, we interpret the upper interval of Santa Cesarea to have been deposited in a high-energy zone, populated by abundant corals (cluster reef, sensu Riding, 2002). Through this zone, sediments produced in the shallower euphotic seagrass meadows were transferred basinward. Indicators are the abundant small epiphytic forms (discorbids–rosalinids, Lobatula and encrusting Planorbulina) and the very conspicuous large porcellaneous foraminifers (Peneroplis, Austrotrillina) that dominate the innermost settings within the meadow (Beavington-Penney et al., 2004). The occurrence of red algae crusts with hooked forms can also be related to transport from seagrass meadows. Articulated red algae have been produced at shallow depths. Large rotalids from the mesophotic zone were also transported through this zone. Similarly, the middle interval represents a high-energy zone where the coarse skeletal grains were channelized between coral mounds (Fig. 6C). For the lower interval, the

abundance of large coral fragments and the mixture of skeletal components transported from the shallow seagrass meadows and elements incorporated from the mesophotic factory (large rotalids, red algae crusts and nodules), suggest deposition at the front of a high-energy cluster reef. High-energy conditions prevented deposition of muddy textures, except within the intraskeletal pores of the coral colonies. 4.3. The Castro Limestone clinobeds The Castro Limestone clinobeds can be clearly observed near Zinzulusa cave, Romanelli cave and Portomiggiano (Zz, Rm and Pm; Fig. 1D). In these localities, few-meter thick beds dip 20° to 30° to the E-SE, abut and onlap a paleo-escarpment developed on the Cretaceous-Eocene stratigraphic units of the ACP. Boundaries can either be transitional or, locally, very irregular and poorly defined surfaces (Fig. 7A, B). In the clinobeds, two lithofacies alternate: coral rudstone with wackestone to packstone matrix (Lithofacies TA) and coral

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Fig. 7. Castro Limestone clinobeds. (A) Romanelli Cave; 20°- to 30°-dipping clinobeds abut onto a Cretaceous substrate (white on the left side of picture). (B) View of the Portomiggiano outcrop. Clinobeds are not bounded by sharp surfaces but can be identified by the alternation of lithofacies TA and TB. (C) Lithofacies TA with cm-sized coral fragments and fine-grained matrix; scale in cm. (D and E) Microfacies TA: badly-sorted, micrite-rich, packstone to wackestone with abundant coral fragments (Cor), encrusted by foraminifers such as acervulinids (Ace) and non-articulated red algae (RA). Other components: Amp: Amphistegina, Rot: Neorotalia, Glo: Globigerinids, Mil: Miliolids.

rudstones containing large and overturned coral colonies with a very coarse grainstone matrix (Lithofacies TB). 4.3.1. Lithofacies TA In Lithofacies TA, coral fragments are small (few cm) (Fig. 7C) and matrix consists of low-sorted bioclastic packstone to wackestone matrix (Fig. 7D, E). Scattered and overturned decimeter-sized coral colonies do locally occur. Skeletal components in the matrix are abundant coral fragments, some encrusted by red algae and foraminifers (acervulinids, victoriellids and Haddonia), cortoids and fragments and crusts of nonarticulated algae. Echinoids, bryozoans, bivalves, brachiopods, articulated red algae and Subterraniphyllum are rare. Among foraminifers, small planktonic forms are abundant; small benthic taxa are frequent and include epiphytic taxa (i.e. cibicidids, discorbids–rosalinids, small miliolids, Planorbulina), textulariids (i.e. Bigenerina), bolivinids and Lenticulina. Large rotalids include fragments of Nephrolepidina, reworked Neorotalia and relatively well-preserved Amphistegina. Symbiont-bearing porcellaneous forms are rare and include fragments and reworked tests of Austrotrillina, Peneroplis and very rare Borelis. 4.3.2. Lithofacies TB Lithofacies TB consists of coral floatstone to rudstone (Fig. 8A), with abundant and large overturned coral colonies and coral fragments (m- to cm-sized). Bosellini and Russo (1992) have reported abundant colonies and fragments of meandroid corals (Hydnophora, Leptoria,

Diploria), large colonies of Astreopora, Thegioastraea and Favia, along with poritids. Some large coral molds and fractures are infilled with laminated glauconitic sand (Bosellini and Russo, 1992) that postdates diagenetic dissolution of corals and cement precipitation. The matrix consists of very coarse and well-cemented grainstone (Fig. 8B). Most conspicuous components in the matrix are coral fragments, red algae and foraminifers. Red algae occur as both fragments and encrusting fragments of corals. Foraminifers include encrusting forms (acervulinids, victoriellids and Haddonia), small benthic forms (many of them epiphytic: discorbids–rosalinids, Planorbulina, Sphaerogypsina, cibicidids, miliolids), large rotalids (abundant reworked Neorotalia tests; fragments and reworked tests of Nephrolepidina, well-preserved thick and flat Amphistegina) and symbiont-bearing porcellaneous taxa (Austrotrillina, Peneroplis, rare Sorites and very frequent Borelis). Other, less abundant, components are fragments of bryozoans, bivalves, decapods, ostracods, articulated algae and Subterraniphyllum. 4.3.3. Interpretation Based on bedding patterns, textures and skeletal composition, these two lithofacies are interpreted as rockfall and debrites (reef talus) deposited at the toe of a paleo-escarpment of the ACP. Most components are either derived both from the reefal belt that developed at the margin of the ACP and from the mesophotic and euphotic back mound area. This transport is reflected in the sediment composition that includes, 1) bioclasts produced in the innermost settings (small epiphytic

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Fig. 8. Castro Limestone lithofacies TB: coral floatstone with coarse grainstone matrix. (A) Clinobeds with cm-to-m-sized moldic pores of corals. (B) Microfacies TB: very-coarse, wellcemented grainstone with coral fragments (Cor), non-articulated red algae (RA), echinoid fragments (Ech), bivalve fragments (Pec: Pectinid fragment) and foraminifers such as Eulepidina (Eul), Borelis (Bor), Amphistegina (Amp). Microcodium (Mic) is resedimented from older rocks (Eocene?).

foraminifers and large porcellaneous taxa produced in the seagrass meadows), 2) mesophotic biota, mostly represented by large rotalids from the grainy (detrital) back-mound area and, 3) coral rubble from the coral buildups. The two types of lithofacies differ in 1) the size of the coral fragments, 2) the type of matrix, and 3) the quantitative distribution of skeletal components. Rudstones with smaller coral fragments embedded in wackestones to packstones (lithofacies TA) contain abundant components indicating deeper water conditions (i.e. planktonic foraminifers, Lenticulina) associated to a muddy matrix (low hydrodynamic energy). Epiphytic taxa are small and scarce, indicating a long distance to the seagrass factory. In contrast, rudstones with large overturned coral colonies and large coral fragments, with coarse-grained grainstone matrix (lithofacies TB) indicate deposition from debris flows and coral failure sourced in a high-energy environment. The abundance of seagrassassociated foraminifers, including large porcellaneous taxa (soritids, Peneroplis and Borelis), along with large rotalids and fragments of articulated algae, requires proximity of the shallow mesophotic and euphotic zones to the edge of the ACP paleo-escarpment. The alternation of facies TA and TB is interpreted to reflect sea-level cyclicity. Lithofacies TA can be associated to a sea-level highstand, when the shallow-water carbonate factory (seagrass) and the mesophotic large rotalids factory shifted landwards onto the flat top of the ACP. In this context, the coral buildups at the edge of the ACP did not develop and the shallow meso- and euphotic factories where away from the margin of the ACP. Coral fragments might have been derived from erosion of pre-existing coral colonies near the edge of the ACP. The muddy matrix is indicative of accumulation below the wave base level, but coral breccia was sourced from the edge of the ACP with higher hydrodynamic conditions. Lithofacies TB in the talus requires higher hydrodynamic conditions at the edge of the ACP and the euphotic- and mesophotic factories to be closer to the margin, to favor the basinward transport and mixture of very shallow-water bioclasts from the innermost settings with others from the mesophotic zone (i.e. large rotalids and red algae). The absence of limemud also suggests high-energy in the deposition loci on the talus. These conditions suggest low relative sea level. 4.4. Depositional model Despite the limitations imposed by the limited lateral continuity of the outcrops, a depositional model can be proposed (Fig. 9). This model is based on the integration of the position of the facies belts with respect to the ACP substrate, the bedding patterns, and the sediment textures and skeletal composition. A zone with luxurious growth of corals occurred near the edge of the ACP paleo-escarpment. In this zone, corals built discrete structures as mounds and cluster reefs. In the mounds, corals had encrusting foraminifers and were associated with some seagrasses, holding epiphytic

foraminifers, which contributed to baffle and trap limemud. The occurrence of these mounds is only evidenced at La Scogliera east (LSa) outcrop, where landward-dipping beds with corals in living position and packstone texture evidence a position in the landward margin of a coral mound. Cluster reefs developed in high-energy zones seaward (and deeper) of the euphotic seagrass zone; they consist of abundant, large and diverse coral colonies surrounded by coarse skeletal grainstone (SC-U). There are no evidences of wave-resistant growth fabrics in both types of coral buildups. This, along with the associated skeletal components, suggests the bathymetric position of the coral buildups to have been below wave base for the coral buildups, in the mesophotic zone. Between cluster reefs, grainstone textures (SC-M) indicate high hydrodynamic conditions. Skeletal composition of these grainstones evidences a mixture of bioclasts from the shallower euphotic zone with in-situ components (rhodoliths, encrusting foraminifers). Seaward of the cluster reefs, the grainstone belt includes large coral fragments (SC-L). Currents flowing in and out of the platform provided the hydrodynamic energy where the cluster reefs developed as suggested by the meter-scale trough cross stratification in the grainstone facies. The lack of good physical correlation between outcrops prevents discerning if these two types of coral buildups (mound vs. cluster) were coeval but occurring in two different hydrodynamic settings, or if they were not contemporary and the different hydrodynamic conditions were related to different water depths. Landward of the coral-dominated belt, carbonate production occurred in relatively low-energy environments in mesophotic conditions; this environment (LSb, in Fig. 9) provided optimal conditions for production of large rotalids (e.g. nummulitids, Neorotalia, Nephrolepidina). The innermost belt was dominated by seagrass meadows in the euphotic zone, on which epiphytic production (including small benthic forms and large porcellaneous taxa) was very important. In the seagrass zone, corals occurred as isolated and scattered colonies whose size progressively decreased towards the internal part. Muddy content of the matrix increased toward the inner part as result of the effectiveness of the seagrass baffling and progressive waveenergy dissipation. These shallow-water facies contain reworked and fragmented tests of deeper biota (nummulitids, lepidocyclinids). Two interpretations can be suggested: the reworked and broken mesophotic components, along with planktonic foraminifers, in the seagrass deposits might be relicts of sediments produced during highstands of sea level that were subsequently admixed by bioturbation or storm reworking during lowstands of sea level. Another plausible explanation might be that the sciaphile biota dwelled in low light conditions under the seagrass-blade canopy. Shell fragmentation and reworking might be associated to the fragility of these flat and thin forms, more prone to breakage than thicker and robust large rotalids such as Amphistegina and Neorotalia.

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Fig. 9. Depositional model for the Castro Limestone (not to scale). Letters denote studied localities (Zz: Zinzulusa; Rm: Romanelli cave; Pm: Portomiggiano; Sc: Santa Cesarea; LS: La Scogliera; see Fig. 1 for location). Water transparency (extinction coefficients of light) determined the bathymetric range of the different facies belts (see Fig. 4).

As the coral belt occurred at the edge of the ACP, on the border of a paleo-escarpment, the bathymetric gradient and talus instability prevented carbonate production seawards of the edge. There, clinobeds resulted from sediment export. These sediments were either produced near the edge (cluster reefs) or transferred there from the shallowwater factories developed on the flat top of the ACP (large rotalids and seagrass). The alternation of two types of lithofacies (TA and TB) on the upper slope (Portomiggiano; Pm in Fig. 9) reflects changes in the composition of sediments shed off the edge, which can be explained by either bathymetric changes at the edge or changes on the distance of the inner factories to the edge, both related to sea-level cyclicity. Lower on the slope (Zinzulusa and Romanelli Cave; Zz and Rm in Fig. 9) the TA- and TB lithofacies alternation is less perceptible and lithofacies TB predominates, suggesting that most coral colonies and sediments were exported during lowstands of sea level. The expression of this sea-level cyclicity in the shallower facies is obscure mostly due to the quality and continuity of the outcrops. Nevertheless, increased sediment instability during sea-level lowstands (higher hydrodynamic energy) on the flat-topped ACP may have decreased the preservation potential of the highstand deposits. Plausibly, continental to brackish-water and shallow-marine Galatone Formation (Esu et al., 1994; Bossio et al., 1998; Margiotta and Ricchetti, 2002) situated to the north and west (landwards) of the studied outcrops, represents the continental-to-marine transition during these highstand episodes when the shoreline migrated landwards. The foraminiferal assemblage of the shallow marine deposits (Esu et al., 1994) is characteristic of seagrass meadows. 5. The Porto Badisco Calcarenite The Porto Badisco Calcarenite has been investigated in the ravine of Porto Badisco (Fig. 1C, E) that, paralleling the depositional dip direction, allows facies characterization from the shallow-water inner belt to the deeper-water outer belt. Six sections were logged and sampled along the eastern margin of the ravine (S1 to S6; Fig. 1E). Additional samples were collected in two localities located in the inner zone of the valley (FC1 and FC2; Fig. 1E). The Porto Badisco Calcarenite is subhorizontally bedded, although bedding planes are obscure as result of bioturbation, but can be recognized by changes in components. Dominant textures

are packstones but, often, grainstone-like texture results from intense late diagenetic corrosion of the muddy matrix. The most prolific carbonate producers were larger benthic foraminifera (LBF), with a significant contribution of red algae. Corals, not previously described in the Porto Badisco Calcarenite, build discrete mounds (few meters to some tens of meters in diameter) but may also occur as scattered colonies. Among LBF, Miogypsinoides, which characterize the late Chattian, are common. Among red algae, melobesioids and sporolithaceans dominate with respect to mastophoroids in the rhodoliths (Brandano et al., 2010). Six lithofacies are distinguished in the Porto Badisco Calcarenite. These lithofacies appear in a recurrent order within beds. They consist, in dip direction, of small benthic foraminifer wackestone–packstone (SG) that, basinward, passes into coral mounds (CM) surrounded by large rotalid packstone (LR), and those, in turn, pass into rhodolithic floatstone (RF) and then into large lepidocyclinid packstone (LL) and into fine calcarenite (FC) in the outer belt. Lithofacies characteristics and interpretation are summarized in Table 2. 5.1. Small benthic foraminifer wackestone–packstone (SG) The small benthic foraminifer wackestone–packstone (SG, Fig. 10A) crops out in localities distantly from the coast (FC1 and FC2). The most conspicuous components in this heterometric packstone are foraminifers and red algae fragments. There are also some resedimented Microcodium fragments. Other minor components are fragments of bryozoans and articulated red algae. Coral fragments, often encrusted by foraminifers and red algae, also occur. In the innermost (inland) outcrops (FC2 in Fig. 1E), foraminifers mostly consist of large porcellaneous taxa including Sorites, Austrotrillina and few specimens of Peneroplis and Borelis (Fig. 10A). Large rotalids such as fragments and reworked Neorotalia, rare fragments of Spiroclypeus and thick Nephrolepidina and few reworked specimens of thick Amphistegina are frequent. Small benthic taxa are abundant and include miliolids, Planorbulina, cibicidids (including Lobatula) and rare discorbids–rosalinids. Finally, encrusting forms on coral fragments consist of victoriellids, rare acervulinids and Haddonia. Basinward, there is a change in components. Here, the small benthic foraminifer wackestone–packstone is poorly sorted and contains abundant foraminifers, coral fragments (encrusted by foraminifers)

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Table 2 Lithofacies, components and interpretation of the Porto Badisco Calcarenite. Lithofacies

Components

Interpretation

Foraminifers Abundant porcellaneous forms, including symbiont-bearing taxa (Sorites, Austrotrillina and few specimens of Peneroplis and Borelis) and small miliolids. Abundant large rotalids (fragments and reworked Neorotalia, rare fragments of Spiroclypeus and thick Nephrolepidina, few reworked specimens of thick Amphistegina are frequent. Basinwards, nummulitids (Spiroclypeus and Heterostegina) become abundant and lepidocyclinids are scarcer. Small rotalid taxa are abundant Planorbulina, cibicidids (including Lobatula) and rare discorbids–rosalinids. Encrusting forms on coral fragments consist of common victoriellids, rare acervulinids and Haddonia. Some planktonics and textulariids occur basinwards. Red algae Abundant non-articulate fragments. Rare articulate fragments. Other minor components Rare fragments of bryozoans, decapods and serpulids. Rare coral fragments infilled with very-fine-grained wackestone to packstone with small benthic foraminifers (discorbids–rosalinids, bolivinids), very small bioclasts and rare planktonic foraminifers. Resedimented Microcodium.

Abundant symbiont-bearing porcellaneous foraminifers (including primary-weed dwellers such as Sorites and Peneroplis) and small forms such as miliolids, Planorbulina, cibicidids and discorbids– rosalinids, with life modes adapted to phytal substrates are indicative of extensive seagrass meadows in euphotic conditions. The occurrence of thick, Amphistegina specimens and articulate red algae are in agreement with shallow-water, well illuminated settings. Poorly sorted, mud-rich textures are in agreement with seagrass meadows where in-situ bioclastic components are baffled by blades and trapped in the rhizomatic mesh. Large rotalids, including nummulitids such indicate mesophotic conditions, under a dense leaf canopy in seagrass meadows. The occurrence of foraminiferal-encrusted coral fragments within the sediment is indicative of the presence of sparse coral colonies within the seagrass meadows. In the outer part of this facies belt, near the coral mounds, the increase of large rotalids with respect to the in-situ seagrass facies, and the occurrence of rare planktonic foraminifers indicate sediment production and accumulation in the deepest parts of seagrass meadows.

Coral mounds (CM) 2–3-m high and 3- to 20-m wide coral mounds, with coral-rudstone flanks abutting around them. Within the mound, coral colonies are mostly in-living position but some large overturned colonies also occur. Most colonies are in contact but enclosed in floatstone/ packstone matrix, and no framework cavities exist. Sediments between corals mostly consist of coral floatstone with fine-grained packstone matrix.

Foraminifers Small benthic taxa are very abundant and include small miliolids, Planorbulina, cibicidids (including Lobatula), discorbids–rosalinids and rare Textularia, Sphaerogypsina, Planorbulina, Glabratella, Bolivina and very rare Discorinopsis and Hofkerina. Large rotalids include frequent fragments of Heterostegina, Nephrolepidina, Neorotalia and rare Miogypsinoides and reworked thick Amphistegina. Porcellaneous symbiont-bearing taxa (Austrotrillina and few specimens of Peneroplis and Borelis) are rare. Encrusting forms on coral fragments consist of common victoriellids, rare acervulinids and Haddonia. Planktonic foraminifers are rare. Red algae Very abundant non-articulate crust fragments (including Sporolithon and mastophoroids-Neogoniolithon). Rare articulate fragments. Other minor components Frequent fragments of echinoids and coral. Rare fragments of bryozoans, brachiopods and bivalves. Very rare gastropod fragments.

Small and discrete coral mounds occurred deeper than seagrass meadows. Fine-grained matrix fills the space within the mound, where the foraminifers, many of them derived from seagrass meadows, evidences transport processes from shallower settings. The presence of small fragments of large porcellaneous forms and rare Amphistegina, Neorotalia and Miogypsinoides tests support this interpretation. The in-situ components are fragmented nummulitids and Nephrolepidina, and reworked coral fragments from the mound and indicate high-energy events. Mound flanks are characterized, in addition to the coral fragments, by very abundant remains of large rotalids, such as Neorotalia, nummulitids, Nephrolepidina, and echinoderm fragments. Nummulitids and Nephrolepidina represent autochthonous/parautochthonous components that lived in meso-oligophotic conditions, reworked and broken by episodic currents and/or storms. These in-situ components were mixed with other bioclasts produced in the mound but also from the shallower seagrass meadows such as thick-shelled Amphistegina and Neorotalia, abundant small epiphytic taxa and large porcellaneous taxa. Abundance of fine-grained, muddy matrix also suggests that these flanks were located below the wave action zone.

Large rotalid packstone to wackestone-packstone (LR)

Foraminifers Large rotalids are very abundant including Neorotalia, frequent to abundant nummulitid fragments (mostly Operculina and Heterostegina), and few Nephrolepidina fragments and slightly reworked Amphistegina also occurs. Large porcellaneous (mostly Austrotrillina and Peneroplis) are frequent. Small benthic taxa include abundant miliolids, frequent cibicidids (e.g. Lobatula) and some acervulinids and nubecularids. Moreover, other foraminiferal taxa occur at deeper settings: Planorbulina, Bolivina, Sphaerogypsina. The encrusting, agglutinate genus Haddonia is frequent. Planktonic taxa are rare and only occur at deeper settings. Red algae Non articulate red algae include melobesioids, mastophoroids (Spongites) and Sporolithon. Basinward, the amount of rhodoliths, red-algae nodules (including Sporolithon), crusts and fragments increase, including very rare articulate-algae fragments and remains of the peyssonelliacean Polystrata alba. Other minor components Other frequent components are fragments of echinoderms, bryozoans, bivalves and corals.

This facies contains a mixture of in-situ mesophotic components (nummulitids and Nephrolepidina) and shallower components (Neorotalia, thick Amphistegina, Austrotrillina, Peneroplis, small miliolids, discorbids–rosalinids, Planorbulina). Thick Neorotalia would dwell at shallow environments either uncovered or colonized by seagrass meadows that would have been transported basinward. Downdip increase of large rotalids, especially flat nummulitids, and non-articulate red algae are indicative of meso-oligophotic conditions, which is consistent with the increasing depth, and decreased benthonic production/ accumulation, pointed out by the occurrence of planktonic foraminifers. Poor-preservation and fragmentation of the large rotalid tests is indicative of high hydrodynamic energy. Downdip transport is also inferred from the mixture of seagrass meadows components (large porcellaneous and epiphytic foraminifers) and other shallow-water components (thick Amphistegina tests and articulate red algae) with autochthonous large rotalids and coral fragments. The mixture of shallow-water red-algal taxa such as mastophoroids, with deeper melobesioids confirms this interpretation.

Porto Badisco Small benthic foraminifer wackestone-packstone (SG)

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Table 2 (continued) Lithofacies Porto Badisco Rhodolithic floatstone (locally rudstones) with packstone matrix (RF) Matrix varies from grain-dominated to mud-dominated packstone

Fine calcarenite (FC) Fine-grained bioclastic packstone to wackestone with well-sorted and highly abraded biogenic components. Grainstone-like texture due to intense diagenetic corrosion of the micritic matrix

Vitigliano Structureless packstone to grainstone (locally rudstone/ floatstone) with scattered coral colonies

Components

Interpretation

Red algae Red algae are highly bioeroded. Rhodolith structure is mostly laminar and includes Mesophyllum, Sporolithon, Lithothamnion, often with bryozoan nucleous and encrusted by acervulinid foraminifers. Articulated algae are rare. Foraminifers Large rotalids are abundant, including reworked tests and fragments of large Eulepidina, nummulitids, Neorotalia, frequent Nephrolepidina and thick Amphistegina specimens and rare Miogypsinoides fragments. Large porcellaneous foraminifers are scarce and only represented by Austrotrillina. Small benthic taxa are frequent and consist of discorbids– rosalinids, cibicidids, small miliolids, textulariids and bolivinids. Encrusting forms are very rare and only represented by Sphaerogypsina. Planktonic foraminifers are very rare. Other minor components Frequent fragments of echinoids and bryozoans. Rare fragments of decapods, brachiopods and bivalves. Very rare gastropod fragments.

In the outer part of this facies belt, the occurrence of nummulitids and lepidocyclinids (including fragments of large, flat Eulepidina), scattered rhodoliths, fragments of redalgal nodules and crusts and fragments of peyssonelliacean Polystrata alba situate this environment within the oligophotic zone. Large and flat Eulepidina abundantly thrived in the deeper part of the oligophotic zone, downdip of rhodolithic pavements. Other autochthonous foraminifers were nummulitids and Nephrolepidina. The abundance of planktonic taxa also suggests some deeper conditions or, at least, a decrease of the production rate of benthonic production. The reworking of relatively deeper-water components (i.e. nummulitids), the laminar structure of the rhodoliths indicating a rapid turnover, and a decrease of mud proportion in the matrix suggest some hydrodynamics. Seagrass components (thick Amphistegina and Neorotalia, small miliolids, discorbids–rosalinids and cibicidids) were swept from shallow-water settings.

Foraminifers Large rotalids consist of reworked tests and fragments of Miogypsinoides, Neorotalia, lepidocyclinids, nummulitids and thick Amphistegina. Small benthic taxa include discorbids–rosalinids and Lobatula. Red algae Abundant, highly-abraded red algae fragments. Other minor components Highly-abraded echinoid plates and spines.

These fine-grained, bioclastic deposits represent the distal accumulation of small, well-sorted, skeletal components in a zone with very scarce carbonate production, probably in dysphotic/aphotic conditions. These sediments were shed off from all shallower settings, from the seagrass meadows (small epiphytic taxa-discorbids–rosalinids and Lobatula-, thick Amphistegina, Miogypsinoides and Neorotalia) down to oligophotic settings with flat nummulitids and large lepidocyclinids

Corals Corals are abundant, commonly encrusted by red algae and locally bored by bivalves. Dominant genera are Porites, Pavona, Favites, Tarbellastraea; Hydnophora and Actinacis are scarcer. Foraminifers Large rotalids are abundant and consist of reworked Nephrolepidina, nummulitids (mostly Spiroclypeus), Neorotalia and Amphistegina. Reworked symbiont-bearing porcellaneous taxa (Austrotrillina, Peneroplis) are frequent. Small benthic taxa including cibicidids, Planorbulina, miliolids and textulariids are frequent. Large encrusting forms such as victoriellids and large agglutinated Haddonia are rare. In the muddier samples Miogypsinoides fragments occur. Red algae Non-articulated red-algal fragments are very abundant. Articulate-algae fragments are rare. Other minor components Echinoderm fragments are abundant. Other, less frequent, bioclasts are bryozoans and bivalves.

Poorly sorted textures with muddy matrix, along with the absence of sedimentary structures, point to seagrassassociated deposits composed of both transported and autochthonous components trapped by the rhizomes. The rhizomatic trapping impedes the formation of sedimentary structures. The occurrence of epiphytic foraminifera supports this interpretation. These forms include small benthic taxa (Planorbulina, cibicidids, miliolids and textulariids), large porcellaneous forms interpreted as primary weed-dwellers (Austrotrillina and Peneroplis) and large rotalids such as thick Amphistegina, Neorotalia and Miogypsinoides. The latter interpreted to live attached to the plant and adapt the growth form to the phytal substrate. Despite seagrass meadows are situated in the euphotic zone, oligophotic conditions occur close to the bottom below dense leaf canopies. In these conditions, organisms often associated to deeper settings may also thrive. That is the case of large flat nummulitids (Spiroclypeus) and lepidocyclinids (Nephrolepidina). All these characteristics allow interpretation of the facies cropping out at Vitigliano as the transition from the deeper part of euphotic seagrass meadows to the mesophotic zone with large rotalids and coral mounds

particularly near coral mounds (FC1 in Fig. 1E), non-articulated redalgae fragments and frequent echinoid fragments. Other bioclasts consist of bryozoan remains, fragments of articulate red algae and rare fragments of decapods and serpulids. Among foraminifers, large rotalids are abundant (mostly Heterostegina and Spiroclypeus), reworked Neorotalia and some Amphistegina. Very rare fragments of lepidocyclinids occur. Encrusting foraminifers (victoriellids and acervulinids) are common. Large porcellaneous taxa are frequent and include Austrotrillina, few Peneroplis and rare Borelis. Small benthic taxa include abundant

miliolids, textulariids and rotalids (cibicidids, discorbids–rosalinids, Planorbulina). Coral intraskeletal pores are infilled with very-finegrained wackestone to packstone with small benthic foraminifers (discorbids–rosalinids, bolivinids), very small bioclasts and rare planktonic foraminifers. Interpretation — Abundant symbiont-bearing porcellaneous foraminifers (including primary-weed-dwellers–sensu Brasier, 1975–such as Sorites and Peneroplis) and small forms such as miliolids, Planorbulina, cibicidids and discorbids–rosalinids, with life modes adapted to phytal

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Fig. 10. Porto Badisco microfacies. (A) SG microfacies: poorly sorted small-benthic foraminifers wackestone to packstone. (B) CM microfacies: fine-grained packstone with scattered coral fragments. (C) LR microfacies: large-rotalid-rich packstone with abundant Neorotalia, nummulitid and lepidocyclinid fragments, and encrusting foraminifers such as Sporadotrema. (D) RF microfacies: packstone with abundant LBF and red-algal fragments. (E) LL microfacies: grain-dominated packstone with abundant large Eulepidina. (F) FC microfacies: fine-grained bioclastic packstone to wackestone with well-sorted skeletal fragments. Foraminifers: Amp: Amphistegina, Aus: Austrotrillina, Bor: Borelis, Het: Heterostegina, Lep: Lepidocyclinid, Mil: Miliolids, Nep: Nephrolepidina, Num: Nummulitid, Ope: Operculina, Pla: Planorbulina, Rot: Neorotalia, Sor: Soritid, Spi: Spiroclypeus, Spo: Sporadotrema, Tex: Textulariids. Ech: Echinoid fragment, RA: non-articulated red-algal fragments, Cor: Coral fragment, Biv: Bivalve fragment.

substrates (see Brasier, 1975; Langer, 1993; Mateu-Vicens et al., 2008a, 2010) are indicative of extensive seagrass meadows in euphotic conditions (Figs. 4, 11). The occurrence of thick, well-preserved Amphistegina specimens and articulate red algae is in agreement with shallow-water, well-illuminated settings. Similarly, Neorotalia and thick lepidocyclinids (Nephrolepidina) have been reported in facies characteristic of shallowwater seagrass meadows (Hallock and Glenn, 1986; Bassi and Nebelsick, 2010). Poorly sorted, micrite-rich textures are in agreement with sediment baffling by seagrass meadows where in-situ bioclastic components are baffled by blades and, along with allochthonous components, trapped in the rhizomatic mesh (Davies, 1970; Scoffin, 1970; Brasier, 1975; Pomar et al., 2002; Beavington-Penney et al., 2004). Large rotalids, including nummulitids such as Spiroclypeus, and Nephrolepidina indicate mesophotic conditions (Brandano et al., 2009a, 2009b). Commonly, the mesophotic conditions occur at greater water depths, but they also occur in shallow water under a dense leaf canopy in seagrass meadows (Reuter et al., 2011). Additionally, even if

modern nummulitids tend to occupy deeper, calm, oligophotic environments, in the past this family, including extant genera, occupied a wider bathymetric range (Hottinger, 1997; Boudagher-Fadel et al., 2000; Boudagher-Fadel, 2008). The occurrence of foraminiferal-encrusted coral fragments within the sediment is indicative of the presence of sparse coral colonies within the seagrass meadows. In the outer part of this facies belt, near the coral mounds, the increase of large rotalids with respect to the in-situ seagrass facies and the occurrence of rare planktonic foraminifers indicate sediment production and accumulation in the deepest parts of seagrass meadows. 5.2. Coral mounds (CM) The coral mounds (CM) occur seaward of the seagrass meadow deposits (SG). The mounds are 2–3-m high and 3- to 20-m wide, and coral-rudstone flanks abut around them. Within the mound, coral colonies are mostly in living position but some large overturned colonies

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Fig. 11. Relative proportion (thin-section estimations) of in-situ skeletal components along dip direction in the Porto Badisco Calcarenite. LL: large lepidocyclinid packstone; RF: rhodolithic floatstone; CM: coral mounds; LR large rotalid packstone; SG: Seagrass beds (small benthic foraminifer wackestone–packstone).

also occur. Most colonies are in contact but enclosed in floatstone/ packstone matrix, and no framework cavities exist. Mound structure fits better as segment- to cluster reef rather than a frame reef3 (sensu Riding, 2002). In the mounds, the sediments between corals mostly consist of coral floatstone with a fine-grained packstone matrix (Fig. 10B). Most abundant components are non-articulate red algal fragments, small benthic foraminifers and small fragments of LBF. Echinoid fragments are frequent. Fragments of bryozoans, brachiopods, bivalves and articulate red-algae also occur. Coarse fragments of LBF and bryozoans are scarce. Among foraminifers, small benthic taxa dominate and they include abundant miliolids, frequent bolivinids, cibicidids, discorbids– rosalinids, Planorbulina. Textularia also occurs. Large forms include frequent fragments of large rotalids such as Heterostegina, Nephrolepidina, Neorotalia and rare Miogypsinoides and reworked thick Amphistegina. Porcellaneous large forms include some reworked Borelis and rare Peneroplis. Planktonic foraminifers are rare. Meter-sized coral-rudstone deposits abut as flanks around the coral mounds. The rudstone matrix consists of very-coarse packstone to wackestone with very abundant large rotalids and fragments of nonarticulate red algae crusts, including Sporolithon and mastophoroids (Neogoniolithon). Other components are fragments of coral, frequent echinoids and scarce bivalves and bryozoans; gastropods are rare and articulate red algae very rare. Among foraminifers, large rotalids dominate with very abundant reworked Neorotalia, abundant nummulitid fragments, and frequent fragments of Nephrolepidina and preserved thick Amphistegina. Large porcellaneous forms (Austrotrillina and Peneroplis) are rare. Small benthic forms include abundant miliolids, frequent cibicids such as Lobatula, discorbids–rosalinids, rare Sphaerogypsina, Planorbulina, Glabratella, Bolivina and Textularia, and very rare Discorinopsis and Hofkerina. Interpretation — Optimal conditions for corals to grow occurred deeper than the seagrass meadows, but they did not form wave3 From Riding (2002): Frame reefs: skeletal reefs in which essentially in place skeletons are in contact; characterized by relatively high skeleton/matrix ratio. By creating partly open shelter cavities, skeletal support may facilitate early cementation.

resistant rigid framework structures up to sea level. They built small and discrete mounds (Fig. 11). Fine-grained matrix filled the space within the mound, where the small-sized skeletal components were baffled and trapped. The abundance of small benthic foraminifers, many of them derived from seagrass meadows, evidences transport processes from shallower settings. The presence of small fragments of large porcellaneous forms and rare Amphistegina, Neorotalia and Miogypsinoides tests supports this interpretation. The latter has been reported as a reliable seagrass indicator since the test shape is accommodated to the phytal substrate during the foraminiferal growth (Boudagher-Fadel, 2008). The in-situ components are fragmented nummulitids, Nephrolepidina, and reworked coral fragments from the mound, indicating high-energy events. Mound flanks are characterized, in addition to the coral fragments, by very abundant remains of large rotalids, such as Neorotalia, nummulitids, Nephrolepidina, and echinoderm fragments. Nummulitids and Nephrolepidina represent autochthonous/parautochthonous components that lived in meso-oligophotic conditions, reworked and broken by episodic currents and/or storms. These in-situ components were mixed with other bioclasts produced in the mound but also from the shallower seagrass meadows such as thick-shelled Amphistegina and Neorotalia, abundant small epiphytic taxa (miliolids, Lobatula, discorbids–rosalinids, Glabratella, encrusting Planorbulina and Sphaerogypsina) and large porcellaneous taxa. Abundance of fine-grained, muddy matrix also suggests that these flanks were located below the wave action zone. 5.3. Large rotalid packstone (LR) The large rotalid packstone to wackestone–packstone (LR) occurs seaward of the seagrass packstone–wackestone (SG) and around and seaward of the coral mounds (CM). The most conspicuous components are fragments and reworked Neorotalia (Fig. 10C). Nummulitid fragments (mostly Operculina and Heterostegina) are frequent, and few Nephrolepidina fragments and slightly reworked Amphistegina also occur. Large porcellaneous foraminifers (mostly Austrotrillina and Peneroplis) are frequent. Small benthic taxa include abundant miliolids, frequent cibicidids (e.g. Lobatula) and some acervulinids and

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nubecularids. The encrusting, agglutinate genus Haddonia is frequent. Non-articulate red algae include melobesioids, mastophoroids (Spongites) and Sporolithon. Other frequent components are fragments of echinoderms, bryozoans, bivalves and corals. Lithoclasts are rare. Basinward, the amount of rhodoliths, red-algae nodules (including Sporolithon), crusts and fragments increase, including very rare articulate-algae fragments and remains of the peyssonelliacean Polystrata alba. Among large rotalids, Neorotalia remains frequent with increasing depth, while nummulitids and Nephrolepidina become abundant and thick Amphistegina specimens and small miliolids and discorbids–rosalinids are frequent, and large porcellaneous foraminifers occur rarely. Moreover, other foraminiferal taxa occur at deeper settings: Planorbulina, Bolivina, Sphaerogypsina and rare planktonic taxa. Interpretation — This facies contains a mixture of in-situ components (nummulitids and Nephrolepidina) and shallower, transported components (Neorotalia, thick Amphistegina, Austrotrillina, Peneroplis, small miliolids, discorbids–rosalinids, Planorbulina). Thick Neorotalia would have dwelled in shallow environments (Hottinger, 1997), either uncovered or colonized by seagrass meadows (Bassi and Nebelsick, 2010), and would have been transported basinward (Fig. 11). Downdip increase of large rotalids, especially flat nummulitids, and non-articulate red algae are indicative of meso-oligophotic conditions, which is consistent with the increasing depth, or decreased benthonic production/accumulation, pointed out by the occurrence of planktonic foraminifers. Poor preservation and fragmentation of the large rotalid tests is indicative of high hydrodynamic energy. Intense transport processes are also inferred from the mixture of seagrass-meadow components (large porcellaneous and epiphytic foraminifers) and other shallow-water components (thick Amphistegina tests and articulate red algae) with autochthonous large rotalids and coral fragments. The mixture of shallow-water redalgal taxa such as mastophoroids, with deeper melobesioids confirms this interpretation. In the outer part of this facies belt, the occurrence of nummulitids and lepidocyclinids (including fragments of large, flat Eulepidina), scattered rhodoliths, fragments of red-algal nodules and crusts, and fragments of peyssonelliacean Polystrata alba situate this environment within the oligophotic zone (Fig. 4). Brandano et al. (2009a, 2009b) interpreted a similar facies in Malta to be produced at 20–30 m of water depth. 5.4. Rhodolithic floatstone (RF) The rhodolithic floatstone (RF), locally rudstone, occurs seaward of the large rotalid packstone belt. Rhodolith structure is mostly laminar and includes Mesophyllum, Sporolithon, Lithothamnion, often with bryozoan nucleus and encrusted by acervulinid foraminifers. Red algae are highly bioeroded. Matrix is a packstone with abundant large rotalids, including reworked tests and fragments of large Eulepidina, nummulitids, Neorotalia, frequent Nephrolepidina and thick Amphistegina specimens (Fig. 10 D). Rare Miogypsinoides fragments also occur. Large porcellaneous foraminifers are scarce and only represented by Austrotrillina. Notwithstanding, small benthic taxa are frequent and consist of discorbids–rosalinids, cibicidids, small miliolids, textulariids and bolivinids. Very rare encrusting Sphaerogypsina and planktonic forms also occur. Components other than foraminifers are frequent bryozoan and echinoid fragments, and rare bivalve, decapod, brachiopod and articulate red-algae fragments. Interpretation — In the oligophotic zone (Fig. 4), red-algal rhodoliths became more abundant (Fig. 11). They present laminar structures and include both mastophoroid taxa in the inner layers that pass into melobesioid taxa in the external parts, which indicate turnover and transport to deeper settings during the rhodolith growth. This basinward sediment transport is also recorded by the occurrence of shallow-water components mostly corresponding to seagrassassociated biota. Changes in the foraminiferal assemblage also confirm the depth increase, as indicated by the occurrence of in-situ thin and flat Eulepidina specimens.

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5.5. Large lepidocyclinid packstone (LL) The large lepidocyclinid packstone (LL) consists of grain-dominated packstone to mud-dominated packstone (sensu Lucia, 1995) with very abundant, slightly broken and very large Eulepidina (Fig. 10E). Large rotalids, other than Eulepidina, are abundant nummulitids (reworked), well-preserved Amphistegina, Neorotalia and frequent Nephrolepidina. Encrusting foraminifers such as victoriellids and acervulinids are abundant. Small benthic foraminifers are frequent and include discorbids– rosalinids, cibicidids, miliolids and scarcer bolivinids and textulariids. Planktonic foraminifers are abundant. Components other than foraminifers include abundant non-articulate red algae, forming laminar rhodoliths, including the genus Mesophyllum. Indeterminate red-algal fragments are also abundant. Bryozoan fragments are frequent, and fragments of bryozoans, bivalves and articulate red algae are rare. Interpretation — Large and flat Eulepidina abundantly thrived in the deeper part of the oligophotic zone (Fig. 4), downdip of rhodolithic pavements (Fig. 11). Other autochthonous foraminifers were nummulitids and Nephrolepidina. The abundance of planktonic taxa also suggests some deeper conditions or, at least, a decrease of the production rate of benthonic production. The reworking of relatively deeper-water components (i.e. nummulitids), the laminar structure of the rhodoliths indicating a rapid turnover (Bosence, 1983; Brandano et al., 2005), and a decrease of limemud proportion in the matrix suggest some hydrodynamics. Seagrass components (thick Amphistegina and Neorotalia, small miliolids, discorbids–rosalinids and cibicidids) swept from shallowwater settings also occur in this facies belt. 5.6. Fine calcarenite (FC) Seaward of the large lepidocyclinid packstone (LL), the fine calcarenite consists of fine-grained bioclastic packstone to wackestone with well-sorted and highly abraded biogenic components, dominated by red algae detritus, echinoid plates and spines, large rotalids and small benthic foraminifers (Fig. 10F). Intense diagenetic corrosion of the muddy matrix confers a grainstone-like texture to this facies. LBF consist of reworked tests and fragments of Miogypsinoides, Neorotalia, lepidocyclinids, nummulitids and thick Amphistegina. Small benthic taxa include discorbids–rosalinids and Lobatula. Interpretation — These fine-grained, bioclastic deposits represent the distal accumulation of small, well-sorted, skeletal components in a zone with very scarce carbonate production, probably in dysphotic/aphotic conditions. These sediments were shed from all shallower settings, from the seagrass meadows (small epiphytic taxa-discorbids–rosalinids and Lobatula, thick Amphistegina, Miogypsinoides and Neorotalia) down to oligophotic settings with (Fig. 4) flat nummulitids and large lepidocyclinids. 5.7. Outcrop near Vitigliano Near Vitigliano, structureless packstone to grainstone, locally rudstone/floatstone, with large and scattered coral colonies crops out in a road cut, around two meter high. Most corals are in life position but some are overturned. This facies was previously interpreted as backreef lagoon of the lower Chattian Castro Limestone (Bosellini and Russo, 1992; Bosellini and Perrin, 1994). This interpretation was based on the landward position of the outcrop with respect to the margin of the platform (see Fig. 1D) and the age interpretation was based in the presence of Nephrolepidina praemarginata (Bosellini and Russo, 1992). Nevertheless, the co-occurrence of Miogypsinoides and N. praemarginata places the age of the Vitigliano rocks at the base of zone SB23 (cf. Cahuzac and Poignant, 1997), equivalent to the base of Porto Badisco Calcarenite. The packstone to grainstone, locally wackestone, sediments contain very abundant non-articulated red-algal fragments and foraminifers. Echinoderm fragments are abundant. Other, less frequent, bioclasts

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are bryozoans, bivalves and articulated red algae. Among foraminifers, large rotalids are conspicuous and consist of reworked Nephrolepidina, nummulitids (mostly Spiroclypeus), Neorotalia and Amphistegina. Reworked symbiont-bearing porcellaneous taxa (Austrotrillina, Peneroplis) and small benthic taxa including cibicidids, Planorbulina, miliolids and textulariids are frequent. Large encrusting forms such as victoriellids and large agglutinated Haddonia are rare. In the muddier samples Miogypsinoides fragments occur. Based on quantitative analysis of the coral fauna based in both linear and areal measurements, Bosellini and Perrin (1994) estimated corals to form 20% of the rock. Corals are commonly encrusted by red algae and locally bored by bivalves. Among corals, Porites, Pavona, Favites, and Tarbellastraea are the dominant genus, whereas Hydnophora and Actinacis are less frequent (Bosellini and Perrin, 1994). Interpretation — Poorly sorted textures with micritic matrix, along with the absence of hydrodynamic sedimentary structures, point to seagrass-associated deposits composed of both transported and autochthonous components trapped by the rhizomes. The rhizomatic trapping impedes the formation of sedimentary structures. The occurrence of epiphytic foraminifera (Brasier, 1975; Langer, 1993; Mateu-Vicens et al., 2008a) supports this interpretation. These forms include small benthic taxa (Planorbulina, cibicidids, miliolids and textulariids), large porcellaneous forms interpreted as primary weed-dwellers (sensu Brasier, 1975) (Austrotrillina and Peneroplis) and large rotalids such as thick Amphistegina, Neorotalia and Miogypsinoides. The latter are interpreted to live attached to the plant and adapt the growth form to the phytal substrate. Even if seagrass meadows are situated in the euphotic zone, oligophotic conditions occur close to the bottom below dense leaf canopies. In these conditions, organisms often associated to deeper settings may also thrive there. This is the case of large flat nummulitids (Spiroclypeus) and lepidocyclinids (Nephrolepidina). All these characteristics allow interpreting the facies cropping out at Vitigliano as the transition from the deeper part of euphotic seagrass meadows to the mesophotic zone with large rotalids and coral mounds. 5.8. Depositional model Within beds, the above described lithofacies recurrently occur in the same order: small benthic foraminifer wackestone-packstone (SG), pass downdip into large rotalid packstone (LR) and coral mounds (CM), and subsequently into rhodolithic floatstone (RF), large lepidocyclinid

packstone (LL) and fine calcarenite (FC). Skeletal components indicate a progressive increase in water depth from the euphotic seagrass deposits (SG) to the oligophotic large lepidocyclinid packstone (LL) and, probably aphotic fine calcarenite (FC) (Fig. 11). No break on the slope angle is observed (Fig. 12). This clearly indicates that this carbonate system was a homoclinal ramp in which small coral buildups were not able to build a barrier up to sea level. The source of the hydraulic energy is difficult to determine. There are no sedimentary structures preserved, bioturbation is ubiquitous, and muddy textures are dominant. In the shallow-water zone, extensive seagrass meadows (SG) developed. In this euphotic zone, surface waves commonly provide hydrodynamic energy. The carbonate sediments produced within the seagrass, both skeletal grains and limemud, were partially baffled by the blades and trapped in the rhizomatic mesh, but also transferred downdip, preferentially the small benthic foraminifers. Basinward, like in the Castro Limestone, light and seagrasses decreased allowing a “sandy” seafloor to develop in mesophotic conditions, in which the most prolific carbonate producers were the largerotalid foraminifers (LR). This zone was also the optimal for corals to thrive (CM), where they built small and discrete mounds (cluster reefs). These coral mounds were not continuous and they did not build a rigid structure up to sea level. Impoverishment of coral assemblages and the absence of reefal frameworks in the SE Arabian Gulf has been recently interpreted as result of recurring episodes of coral mass mortality induced by severe sea-surface temperature anomalies operating on a decadal time-scale (Purkis and Riegl, 2005). Consequently, the seagrass belt cannot be considered a shallow-water back-reef lagoon similar to the modern Caribbean model. Downdip, and already in the oligophotic zone, red algae thrived well and produced rhodoliths (RF). The preservation of limemud in the matrix in these lithofacies (LR, CM and RF) suggests the large-rotalid/coral-mound/rhodolithic rudstone zones were below wave base. Nevertheless, episodic hydrodynamic energy was needed in order to: 1) shed down-ramp some of the components produced in these zones, 2) provide the water turbulence for corals to thrive (e.g., Bilger and Atkinson, 1992; Hearn et al., 2001; Ribes et al., 2003; Pomar and Hallock, 2008; Pomar et al., 2012) and 3) turnover of the rhodoliths. Deeper in the oligophotic zone, large and flat lepidocyclinid Eulepidina abundantly thrived along with nummulitids and Nephrolepidina. Here, some hydrodynamic energy is needed to explain the decrease of

Fig. 12. Depositional model for the Porto Badisco Calcarenite (not to scale). Water transparency (extinction coefficients of light) determined the bathymetry of the different facies belts (see Fig. 4).

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limemud in the matrix and the reworking of relatively deeper-water nummulitids. 6. Discussion Critical analysis of carbonate systems requires observation of the complete facies array along the depositional profile, including rock textures and components to avoid a possible bias induced by the uniformitarian viewpoint (Pomar and Hallock, 2007). The two stratigraphic units here studied, the Castro Limestone and the Porto Badisco Calcarenite,

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offer this opportunity. Both units represent carbonate ramps; the Castro Limestone is a distally steepened ramp due the occurrence of a paleo-escarpment in the Eocene–Cretaceous substrate, and the Porto Badisco Calcarenite is homoclinal. In both units, extensive seagrass meadows occupied the shallowwater wave-agitated zones (Fig. 13), in which epiphytic biota and sediment dweller organisms dominated the carbonate production. There, the seagrass blades principally dissipated surface-wave energy and the rhizomatic mesh trapped both skeletal components and limemud, producing packstone textures. Although seagrasses preferentially grow in

Fig. 13. Cartoon depicting the conceptual model for deposition of the Chattian carbonates in Salento in relation to sea-level changes. Not to scale. The Castro Limestone and the Porto Badisco Calcarenite have similar shallow-water facies belts: The euphotic seagrass meadows and the mesophotic large rotalids with coral mounds. Differences in the oligophotic facies belts are related to substrate availability. Facies belts shifted landward and basinward according to changes of sea level. High-energy events in the meso-oligophotic zones are better explained by breaking internal waves (IWs) rather than surface storm waves. Facies color codes and ornaments as in Figs. 9 and 12.

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well-lit areas (euphotic conditions), some meso- and oligophotic biota might thrive below a dense blade canopy. Lightweight (low bulk density) and small skeletal grains were easily entrained and transferred downdip by storms. Scarce coral colonies did also occur below the seagrass canopy. In the mesophotic zone, in both the Castro Limestone and the Porto Badisco Calcarenite, large rotalid foraminifers thriving in relatively low hydrodynamic energy (below surface-wave action) dominated carbonate production (Fig. 13). The most conspicuous one was Neorotalia, along with nummulitids (mostly Operculina and Heterostegina), few Nephrolepidina and some Amphistegina, as well as some nonarticulated red algae. Also in the mesophotic zone, corals built discrete mounds. These mounds fit in the cluster reef category of Riding (2002) with no evidences of wave-resistant growth fabrics. Cluster reefs are matrix-supported reefs in which in-place skeletons are adjacent but not in contact. They are characterized by 1) relatively high matrix/skeleton ratios, 2) low volumes of extra-skeletal early cement and 3) absence of framework (Riding, 2002). The modern Caribbean barrier-reef shelf-lagoon complex model cannot be applied to these Oligocene coral mounds. A key point here is the source of hydrodynamic energy, which raises an apparent paradox: the need to explain episodic high-turbulence events in a context of low-energy ambient conditions, in the mesooligophotic zones, independent from surface storm waves. Surface storm waves would be a simple way to explain the origin of this episodic turbulence. Nevertheless, the shallow-water facies lacks the thickeningcoarsening upward organization characteristic of a wave-dominated system (Seilacher and Aigner, 1991; Immenhauser, 2009). The facies analysis of these two ramps fails to detect the fair weather- and the storm wave bases as key elements to define and separate the inner, middle and outer ramp (e.g.: Burchette and Wright, 1992). The rationale behind this fact is two-fold: 1) the absence of empirical basis for distinct bimodal separation of fair weather from storm waves (Peters and Loss, 2012); 2) the baffling effect in the shallow-well-lit zone by seagrass meadows (Davies, 1970; Scoffin, 1970; Brasier, 1975; Pomar et al., 2002; Beavington-Penney et al., 2004). In this context, internal waves in the meso-oligophotic zone are good candidates (e.g.: Southard and Cacchione, 1972; Apel, 2002; Bogucki et al., 2005; Thorpe, 2005; Butman et al., 2006; Bourgault et al., 2008; Pomar et al., 2012) although the total absence of sedimentary structures impedes recognizing the precise process. Internal waves propagate through pycnoclines and pycnoclines may occur at any depth. Much of the energy of internal waves dissipates by turbulence in the zone where they intersect a sloping surface, where they break, often causing a swash and backwash flows that can scour the bottom (e.g.: Southard and Cacchione, 1972; Emery and Gunnerson, 1973; Ribbe and Holloway, 2001; Apel, 2002; Fringer and Street, 2003; Cacchione and Pratson, 2004; Bogucki et al., 2005; Thorpe, 2005; Gilbert et al., 2007; Bourgault et al., 2008; Boegman and Ivey, 2009; Lim et al., 2010; Pomar et al., 2012). Butman et al. (2006) emphasized that the main impact of large internal waves on sediment dynamics is usually strongest in midshelf regions and weaker in shallow water, in contrast to surface waves whose impact is strongest near the sea surface and decreases with depth. Additionally, internal waves may generate along-slope currents when approaching a sloping surface from an oblique direction (Thorpe, 1999; Zicanov and Slinn, 2001). Additionally, metazoan mounds require a certain degree of turbulence as vertical accretion of a bioherm increases the impinging efficiency of plankton-carrying currents, thereby favoring suspension feeders (Bilger and Atkinson, 1992; Hearn et al., 2001; Ribes et al., 2003; Pomar and Hallock, 2008; Pomar et al., 2012; Schlager and Purkis, 2013). Suspension-feeder metazoans will produce buildups preferentially at the bathymetry of the pycnocline, a zone of both likely internal-wave propagation and high plankton concentrations. In coastal regions, vertical mixing associated with internal waves may result in significant input of deep-water nutrients and particulate organic matter

into shallow environments (e.g., Sandstrom and Elliott, 1984; Leichter et al., 2003, 2005). In modern Florida Keys, Leichter et al. (1996) have shown dramatic, high frequency variations in temperature, salinity, current velocities, and concentration of chlorophyll-a to be caused by breaking internal waves, and Leichter et al. (1998, 2003, 2005) and Smith et al. (2004) have also shown enhanced growth rates of both benthic algae and suspension feeding corals to be associated with the enhanced fluxes of nutrients and suspended particles with internal waves. In the lower Chattian Castro Limestone, luxurious growth of corals occurred near the sharp edge of the Apulian Carbonate Platform (ACP) substrate. The dominant grainstone textures and the sedimentary structures in the inter-mound sediments clearly indicate high hydrodynamic conditions. Nevertheless, corals did not form an efficient energy dam for surface waves, as they did not build the mound up to sea level. An effective source of hydrodynamics in the mesophotic zone is the occurrence of internal waves (Fig. 13). As the coral mounds in the Castro Limestone are at the edge of the ACP, currents moving in and out of the ACP may also be considered. Nevertheless, and despite the uncertainties on the origin of the hydraulic energy, it was strong enough to periodically wipe out coral colonies and sediment from the margin, and to generate gravitational transport (debrites and rockfalls; lithofacies A and B) down the ACP escarpment. The Porto Badisco Calcarenites were deposited away from the margin of the ACP, on a Cretaceous substrate. Here, corals built small and discrete mounds (cluster reefs) within the large rotalids facies belt. In this setting, the hydrodynamic energy was not as important as it was at the edge of the ACP during deposition of the Castro Limestone. Nevertheless, still some hydrodynamics, independent of surface waves, was needed in order to: 1) shed down ramp some skeletal components produced in these zones, 2) provide the turbulence for corals to build the mounds, and 3) energy for the rhodoliths turnover seaward of the coral mounds. Nevertheless, storm energy mostly dissipated in the shallow seagrass zone and no evidences occur about tidal currents. Again here, and despite the absence of direct probes, breaking of internal waves and their induced swash and backwash flows are an efficient mechanism to explain the origin of episodic turbulence in the mesophotic zone of the ramp (Fig. 13). Bádenas et al. (2012) have evidenced swash and backwash flows induced by breaking internal waves on an Upper Jurassic gently sloping ramp. Internal waves are also thought to determine the bathymetric window at which the coral mounds developed (Pomar et al., 2012), providing the high-energy events needed to explain the origin of the flank facies, but also by carrying nutrients and the particulate organic matter for mixotrophs to grow. Alnazghah et al. (2013) have recently evidenced internal waves to control the bathymetric window in which coral-microbial mounds developed in an Upper Jurassic ramp. Deeper in the oligophotic zone, major differences exist in the carbonate factories between the Castro Limestone and the Porto Badisco Calcarenite. For the Porto Badisco Calcarenite, red algae, rhodoliths and large lepidocyclinids (mainly Eulepidina) were very prolific in the oligophotic zone. During deposition of the Castro Limestone, however, the margin of the ACP was too steep and unstable to permit these biotas to thrive. Consequently, there is an important influence of the inherited substrate physiography in controlling the area available for the different carbonate factories. 6.1. Regional vs. global control Despite the control exerted by the available substrate in providing the area available for the different biotas to thrive, other global factors cannot be rejected. In the two Chattian examples analyzed here, corals occur but playing a different role; luxurious occurrence of corals characterizes the Castro Limestone, whereas corals built discrete mounds in the Porto Badisco Calcarenites. In the Porto Badisco Calcarenite, larger benthic foraminifera and red algae dominated carbonate production. In both stratigraphic

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units, corals did not build three-dimensional wave-resistant structures up to sea level, but rather lived in the middle part of the photic zone (mesophotic zone) below the base of the wave action. This position contrasts with optimal habitats for Modern zooxanthellate corals, which require shallow, high light conditions for most rapid reef accretion (e.g., Hallock and Schlager, 1986, and references therein; see Fig. 4). Despite the significant differences between estimates of benthic foraminiferal stable isotopic variations (e.g.: Miller et al., 1987; Zachos et al., 2001; Cramer et al., 2009) and the discrepancies in correlation between biozones and numerical age, the changes in stable isotopic gradient broadly correlates with the changes in skeletal composition (Fig. 14). Coral flourishing during the early Chattian (Castro Limestone), although influenced by the marginal position in the ACP promontory, coincided with low global temperature (δ18O proxy) and low δ13C (Fig. 14). The carbon isotope data is thought to reflect the global carbon cycle related to oceanic productivity but also changes in deep-sea circulation patterns that might trigger or arise from the climatic changes (Zachos et al., 2001). The upper Chattian Porto Badisco Calcarenites accumulated during the latest Oligocene through Early Miocene warming (δ18O decrease) coeval to an increase in δ13C (Fig. 14) characterized by prolific LBF production (e.g., Chaproniere, 1984; Betzler, 1997; Hallock et al., 2006). Hallock and Pomar (2008) also suggested that the influence of internal waves might have been an important mechanism associated with the diversification and extinction of the meso-oligophotic LBF. The influence of internal waves on these habitats likely increased as oceanic latitudinal and bathymetric thermal gradients developed and strengthened episodically through the Cenozoic. As smaller the density contrast is at the pycnocline, the lower the wave frequency and the slower the propagation speed of the internal wave are (Apel, 1987). Consequently, it can plausibly be suggested a decrease in the strength of the pycnocline, associated to the latest Oligocene warming (Zachos et al., 2001; Cramer et al., 2009), during deposition of the Porto Badisco Calcarenite.

Fig. 14. Correlation of deposition of the Castro Limestone and the Porto Badisco Calcarenite against oxygen and carbon isotope curves for the Oligocene (modified from Vandenberghe et al., 2012). This correlation evidences a good correspondence between the Castro Limestone and the cool- and low productivity phase of the early Chattian, and the Porto Badisco Calcarenites with the late Chattian warming phase with a progressive increase in productivity. Oxygen and Carbon isotope curves are from Cramer et al. (2009). SBZ: Paleogene zonation of larger foraminifera (Cahuzac and Poignant, 1997; Serra-Kiel et al., 1998).

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These facts already suggest that coral buildups increased in volume during times of global cooling, whereas temperature increase favors LBF production, and δ13C increase favors algal growth. This possible inverse correlation between coral buildup development and global temperature agrees with Perrin and Kiessling (2012) who already noted, at global scale, a correlation of the global cooling trend from the Eocene to the Miocene with an increase of reef carbonate production and a latitudinal expansion of the reef belt. For the Eocene and Early Oligocene, Höntzsch et al. (2013) have also noted coral reefs to have spread throughout the Tethys during cooling events associated with the demise of many symbiont-bearing larger foraminifera, whereas warming stages favored proliferation of larger benthic foraminifera. 6.2. Other Upper Oligocene examples In the Mediterranean area, a few other examples of Chattian (Upper Oligocene) shallow-water carbonates have recently been described: in Malta (Buxton and Pedley, 1989; Pedley, 1998; Brandano et al., 2009a, 2009b) and in northeastern Italy (Lessini Shelf and Venetian foreland basin; Bassi et al., 2007; Bassi and Nebelsick, 2010). In Malta, the inner ramp facies are characterized by cross-bedded porcellaneous foraminiferal grainstone to packstone passing seaward into seagrass-related sediments with rhodoliths (floatstone to rudstone) and then into bioclastic wackestone/floatstone with scattered coral colonies (Brandano et al., 2009b). Basinward, corals occur in 50- to 150-m-wide patch reefs (Pedley, 1998). Middle ramp facies are characterized by red algae and benthonic foraminifer floatstone to packstone, with an admixture of in-situ and ex-situ components swept out from the inner ramp (Brandano et al., 2009b). Outer ramp facies consists of fine-grained wackestone beds dominated by large and thin Lepidocyclina and erect bryozoan colonies (Pedley, 1998). In northern Italy (Lessini Shelf and Venetian foreland basin), the Chattian homoclinal ramp is characterized by well-developed inner to middle ramp facies (Bassi and Nebelsick, 2010). Inner-ramp crossbedded sandstones pass, basinward, into LBF and miliolid packstones (transition inner/middle ramp) and then into rhodolithic rudstone (proximal middle ramp) and subsequently into Lepidocyclinid packstone of the distal middle ramp. In this carbonate ramp, symbiontbearing corals and green algae are absent (Bassi and Nebelsick, 2010). These two examples share with the Porto Badisco Calcarenites and the Castro Limestone several characteristics: a) they are ramps; b) the middle ramp (meso-oligophotic zones) was the most prolific in terms of carbonate production; c) in the middle ramp, carbonate production was dominated by red algae and LBF; d) corals built mounds in the mesophotic zone, or occurred scattered in the inner ramp; and e) a shallow-water euphotic zone dominated by seagrass-related carbonate production. Main differences are i) the occurrence of rhodolith floatstone/rudstone inside the seagrass facies and coral patches in the deeper part of the inner ramp in the Malta example, and ii) the presence of cross-bedded sandstones in the inner ramp and the absence of corals and green algae in the Italian examples. Another important difference is the luxurious development of corals in the lower Chattian Castro Limestone unparalleled in the Mediterranean examples. Another good example of an Oligocene carbonate ramp is the Asmari Formation (SW Iran), where rotalids, miliolids and imperforate foraminifera are abundant in the inner ramp settings (Vaziri-Moghaddam et al., 2010), red algae and lepidocyclinids dominate the middle ramp, and the outer ramp mostly consists of planktonic foraminiferal mudstones–wackestones (Vaziri-Moghaddam et al., 2006). In the Asmari Formation, van Buchem et al. (2010) have documented large coral buildups, early Chattian in age, to occur in Kuh-e-Razi. There, 60-mthick coral buildups, passing laterally to deeper-water deposits, crop out in several kilometer-long escarpment. Estimated depositional relief for the buildups was about 30- to 40 m. During the late Chattian, however, only smaller coral buildups developed during transgression in the Kuh-e-Khaviz area (Van Buchem et al., 2010). The Asmari Formation

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shares with the Salento examples the decrease of coral buildups as main producers during the upper part of the Chattian, as well as the abundance of red algae and lepidocyclinids that dominate the middle ramp, as in the Porto Badisco Calcarenite. 7. Conclusions Along-dip facies successions in two Chattian carbonate units cropping out in Salento (southern Italy), the Porto Badisco Calcarenites and the Castro Limestone, characterize these examples as carbonate ramps. In both examples, middle ramps (meso-oligophotic zones) were the most prolific in terms of carbonate production, whereas shallow-water seagrass-related production (euphotic) was much less important. Corals built mounds (cluster reefs), also in the mesophotic zone, but never aggraded to sea level. The inherited basement physiography has a strong control on the area available for the different carbonate factories. The lower Chattian Castro Limestone, previously considered as a fringing reef, is here re-interpreted as a distally steepened ramp with a distal talus induced by a paleo-escarpment in the substrate. Near the edge of the escarpment, luxurious growth of corals in the mesophotic zone built segment- to cluster reefs with no evidences of waveresistant growth fabrics (frame reefs). On the slope, downfall of corals and sediments produced 25° to 30° dipping clinobeds abutting against the paleo-escarpment. The upper Chattian Porto Badisco Calcarenite is a homoclinal ramp where larger benthic foraminifera and red algae were the dominant carbonate producers. Basinward of the seagrass meadows, corals only built discrete mounds (cluster reefs) in a mesophotic zone dominated by large rotalid foraminifers. Deeper in the oligophotic zone, red algae, rhodoliths and large lepidocyclinids (Eulepidina) dominated carbonate production. Hydrodynamics in the meso-oligophotic zone, instead of surfacestorm waves, is better explained by breaking internal waves. The change from the luxurious growth of corals in the lower Chattian Castro Limestone to the dominance of larger benthic foraminifera and red algae in the Porto Badisco Calcarenite clearly reflects the control exerted by the substrate physiography. Nevertheless, the possible influence of the mid late Chattian increase in seawater temperature cannot be rejected. Acknowledgments Financial support has been provided by Spanish Research Project CGL2009-13254 (to L.P., G.M-V. and M.M.) and Italian PRIN 20102011, n. 20107ESMX9 (to M.B.). Comments and suggestions by Editor Prof. Finn Surlyk, Samuel J. Purkis and an anonymous reviewer have significantly improved the manuscript. Appendix A. Supplementary data Supplementary data associated with this article can be found in the online version, at http://dx.doi.org/10.1016/j.palaeo.2014.03.023. These data include Google map of the most important areas described in this article. References Aguirre, J., Riding, R., Braga, J.C., 2000. Diversity of coralline red algae: origination and extinction patterns from the Early Cretaceous to the Pleistocene. Paleobiology 26, 651–667. http://dx.doi.org/10.1666/0094-8373(2000)026b0651:DOCRAON2.0.CO;2. Alnazghah, M.H., Bádenas, B., Pomar, L., Aurell, M., Morsilli, M., 2013. Facies heterogeneity at interwell-scale in a carbonate ramp, Upper Jurassic, NE Spain. Mar. Pet. Geol. 44, 140–163. http://dx.doi.org/10.1016/j.marpetgeo.2013.03.004. Apel, J.R., 1987. Principles of Ocean Physics. Academic Press, Ltd., London (634 pp.). Apel, J.R., 2002. Oceanic internal waves and solitons. In: Jackson, C.R. (Ed.), An Atlas of Internal Solitary-like Waves and Their Properties. Global Ocean Associates. Prepared

for Office of Naval Research — Code 322 PO, Alexandria, VA, pp. 1–40 (http://www. internalwaveatlas.com/Atlas2_PDF/IWAtlas_Pg001_Background&Theory.pdf). Bádenas, B., Pomar, L., Aurell, M., Morsilli, M., 2012. A facies model for internalites (internal wave deposits) on a gently sloping carbonate ramp (Upper Jurassic, Ricla, NE Spain). Sediment. Geol. 271–272, 44–57. http://dx.doi.org/10.1016/j.sedgeo. 2012.05.020. Bassi, D., Nebelsick, J.H., 2010. Components, facies and ramps: redefining Upper Oligocene shallow water carbonates using coralline red algae and larger foraminifera (Venetian area, northeast Italy). Palaeogeogr. Palaeoclimatol. Palaeoecol. 295, 258–280. http:// dx.doi.org/10.1016/j.palaeo.2010.06.003. Bassi, D., Hottinger, L., Nebelsick, J.H., 2007. Larger foraminifera from the Upper Oligocene of the Venetian area, north-east Italy. Palaeontology 50 (4), 845–868. http://dx.doi. org/10.1111/j.1475-4983.2007.00677.x. Beavington-Penney, S.J., Wright, V.P., Woelkering, W.J., 2004. Recognising macrophytevegetated environments in the rock record: a new criterion using “hooked” forms of crustose coralline red algae. Sediment. Geol. 166, 1–9. http://dx.doi.org/10.1016/ j.sedgeo.2003.11.022. Bernoulli, D., 2001. Mesozoic–tertiary carbonate platforms, slopes and basins of the external Apennines and Sicily. In: Vai, G.B., Martini, I.P. (Eds.), Anatomy of an Orogen: the Apennines and adjacent Mediterranean basins. Kluwer Acad. Publishers, pp. 307–325. Betzler, C., 1997. Ecological controls on geometries of carbonate platforms: Miocene/Pliocene shallow-water microfaunas and carbonate biofacies from the Queensland Plateau (NE Australia). Facies 37 (1), 147–166. http://dx.doi.org/10.1007/bf02537376. Bilger, R.W., Atkinson, M.J., 1992. Anomalous mass transfer of phosphate on coral reef flats. Limnol. Oceanogr. 37, 261–272. Blanc-Vernet, L., 1969. Contribution à l'étude des Foraminifères de Méditerranée. Extrait du Recueil des Travaux de la Station Marine d'Endoume. Laboratoire de Géologie Marine, Centre d'Océanographie, Centre Universitaire de Luminy, Marseille, France, p. 281. Boegman, L., Ivey, G.N., 2009. Flow separation and resuspension beneath shoaling nonlinear internal waves. J. Geophys. Res. 114, C02018. http://dx.doi.org/10.1029/ 2007JC004411. Bogucki, D.J., Redekopp, L.G., Barth, J., 2005. Internal solitary waves in the Coastal Mixing and Optics 1996 experiment: multimodal structure and resuspension. J. Phys. Oceanogr. 110, C02024. http://dx.doi.org/10.1029/2003JC002253. Borromeo, O., Miraglia, S., Sartorio, D., Bolla, E.M., Andrea, O., Reali, S., Castellanos, C., Villalobos, R., 2011. The Perla World-Class Giant Gas Field, Gulf of Venezuela: depositional and diagenetic controls on reservoir quality in Early Miocene carbonates. AAPG Search and Discovery Article #90135. Bosellini, F.R., 2006. Biotic changes and their control on Oligocene–Miocene reefs: a case study from the Apulia Platform margin (southern Italy). Palaeogeogr. Palaeoclimatol. Palaeoecol. 241, 393–409. http://dx.doi.org/10.1016/j.palaeo.2006.04.001. Bosellini, A., Parente, M., 1994. The Apulia Platform margin in the Salento Peninsula (southern Italy). Giorn. Geol. 56, 167–177. Bosellini, F.R., Perrin, C., 1994. The coral fauna of Vitigliano: qualitative and quantitative analysis in a back reef environment (Castro Limestone, Late Oligocene, Salento Peninsula, southern Italy). Boll. Soc. Paleontol. Ital. 33, 171–181. Bosellini, F.R., Russo, A., 1992. Stratigraphy and facies of an Oligocene fringing reef (Castro Limestone, Salento Peninsula, southern Italy). Facies 26, 146–166. http://dx.doi.org/ 10.1007/BF02539798. Bosellini, A., Bosellini, F.R., Colalongo, M.L., Parente, M., Russo, A., Vescogni, A., 1999. Stratigraphic architecture of the Salento coast from Capo d'Otranto to S. Maria di Leuca (Apulia, Southern Italy). Riv. Ital. Paleontol. Stratigr. 105, 397–416. Bosence, D.W.J., 1983. The occurrence and ecology of recent rhodoliths — a review. In: Peryt, T.M. (Ed.), Coated Grains. Springer-Verlag, New York, pp. 225–242. Bossio, A., Esu, D., Foresi, L.M., Girotti, O., Iannone, A., Luperto, E., Margiotta, S., Mazzei, R., Monteforti, B., Ricchetti, G., Salvatorini, G., 1998. Formazione di Galatone, nuovo nome per un'unità litostratigrafica del Salento (Puglia, Italia meridionale). Atti Soc. Tosc. Sci. Nat., Mem. Serie A 105, 151–156. Boudagher-Fadel, M.K., 2008. Evolution and geological significance of larger benthic foraminifera. Dev. Palaeontol. Stratigr. 21, 1–544. Boudagher-Fadel, M.K., Noad, J.J., Lord, A.R., 2000. Larger foraminifera from Late Oligocene–Earliest Miocene reefal limestones of North East Borneo. Rev. Esp. Micropaleontol. 32, 341–361. Bourgault, D., Kelley, D.E., Galbraith, P.S., 2008. Turbulence and boluses on an internal beach. J. Mar. Res. 66, 563–588. http://dx.doi.org/10.1357/002224008787536835. Brandano, M., Vannucci, G., Pomar, L., Obrador, A., 2005. Rhodolith assemblages from the lower Tortonian carbonate ramp of Menorca (Spain): environmental and paleoclimatic implications. Palaeogeogr. Palaeoclimatol. Palaeoecol. 226, 307–323. http://dx.doi.org/10.1016/j.palaeo.2005.04.034. Brandano, M., Frezza, V., Tomassetti, L., Cuffaro, M., 2009a. Heterozoan carbonates in oligotrophic tropical waters: the Attard member of the lower coralline limestone formation (Upper Oligocene, Malta). Palaeogeogr. Palaeoclimatol. Palaeoecol. 274, 54–63. http://dx.doi.org/10.1016/j.palaeo.2008.12.018. Brandano, M., Frezza, V., Tomassetti, L., Pedley, M., Matteucci, R., 2009b. Facies analysis and palaeoenvironmental interpretation of the Late Oligocene Attard Member (Lower Coralline Limestone Formation), Malta. Sedimentology 56 (4), 1138–1158. http://dx.doi.org/10.1111/j.1365-3091.2008.01023.x. Brandano, M., Morsilli, M., Parente, M., Vannucci, G., Bosellini, F.R., Mateu-Vicens, G., 2010. Rhodolith-rich lithofacies of the Porto Badisco Calcarenite (Upper Chattian, Salento, Apulia, southern Italy). Ital. J. Geosci. 129, 119–131. http://dx.doi.org/10.3301/IJG. 2009.10. Brasier, M.D., 1975. An outline history of seagrass communities. Palaeontology 18, 681–702. Burchette, T.P., Wright, V.P., 1992. Carbonate ramp depositional systems. Sediment. Geol. 79, 3–57. http://dx.doi.org/10.1016/0037-0738(92)90003-A.

L. Pomar et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 404 (2014) 109–132 Butman, B., Alexander, P.S., Scotti, A., Beardsley, R.C., Anderson, S.P., 2006. Large internal waves in Massachusetts Bay transport sediments offshore. Cont. Shelf Res. 26, 2029–2049. http://dx.doi.org/10.1016/j.csr.2006.07.022. Buxton, M., Pedley, H.M., 1989. A standardised model for Tethyan tertiary carbonate ramps. J. Geol. Soc. Lond. 146, 746–748. http://dx.doi.org/10.1144/gsjgs.146.5.0746. Cacchione, D., Pratson, L., 2004. Internal tides. Am. Sci. 2, 130–137. http://dx.doi.org/10. 1511/2004.2.130. Cahuzac, B., Poignant, A., 1997. Essai de biozonation de l'Oligo-Miocène dans les bassins européens à l'aide des grands foraminifères néritiques. Bull. Soc. Géol. France 168, 155–169. Chaproniere, G.C.H., 1984. Oligocene and Miocene larger foraminiferida from Australia and New Zealand. Bulletin — Australia Bureau of Mineral Resources. Geol. Geophys. 188, 1–60. Cramer, B.S., Toggweiler, J.R., Wright, J.D., Katz, M.E., Miller, K.G., 2009. Ocean overturning since the Late Cretaceous: inferences from a new benthic foraminiferal isotope compilation. Paleoceanography 24 (4), PA4216. http://dx.doi.org/10.1029/2008pa001683. Davies, G.R., 1970. Carbonate bank sedimentation, eastern Shark Bay, Western Australia. In: Logan, B.W., Davies, G.R., Read, J.F., Cebulski, D.E. (Eds.), Carbonate Sedimentation and Environments, Shark Bay, Western Australia. American Association of Petroleum Geologists Memoir, 13. AAPG (American Association of Petroleum Geologists), Tulsa, OK, pp. 85–168. Drooger, C.W., Laagland, H., 1986. Larger foraminiferal zonation of the European– Mediterranean Oligocene. Proc. Kon. Ned. Akad Wetensch B 89, 135–148. Emery, K., Gunnerson, C.G., 1973. Internal Swash and Surf. Proc. Natl. Acad. Sci. U. S. A. 70, 2379–2380. Esu, D., Girotti, E., Iannone, A., Pignatti, J.S., Ricchetti, G., 1994. Lagoonal-continental Oligocene of southern Apulia (Italy). Boll. Soc. Paleontol. Ital. 33, 183–195. Fournier, F., Borgomano, J., 2007. Geological significance of seismic reflections and imaging of the reservoir architecture in the Malampaya gas field (Philippines). AAPG Bull. 91, 235–258. http://dx.doi.org/10.1306/10160606043. Frezza, V., Mateu-Vicens, G., Gaglianone, G., Baldassarre, A., Brandano, M., 2011. Mixed carbonate-siliclastic sediments and benthic foraminiferal assemblages from Posidonia oceanica seagrass meadows of the central Tyrrhenian continental shelf (Latium, Italy). Ital. J. Geosci. 130, 352–369. http://dx.doi.org/10.3301/IJG.2011.07. Fringer, O.B., Street, R.L., 2003. The dynamics of breaking progressive interfacial waves. J. Fluid Mech. 494, 319–353. http://dx.doi.org/10.1017/S0022112003006189. Frost, S.H. (Ed.), 1977a. Oligocene Reef Coral Biogeography, Caribbean and Western Tethys. Mem. B.R.G.M., 89 (Paris, 342–352 pp.). Frost, S.H., 1977b. Ecologic controls of Caribbean and Mediterranean Oligocene reef-coral communities. Proc. 3rd. Int. Coral Reef Symp., Miami, Miami, pp. 367–373. Frost, S.H., 1981. Oligocene reef coral biofacies of the Vicentin, northeast Italy. In: Toomey, D.F. (Ed.), European Fossil Reef Models. SEPM Spec. Publ., pp. 483–539. Gilbert, R.W., Zedler, E.A., Grilli, S.T., Street, R.L., 2007. Progress on nonlinear‐wave‐forced sediment transport simulation. IEEE J. Ocean. Eng. 32 (1), 236–248. http://dx.doi.org/ 10.1109/JOE.2007.890979. Grötsch, J., Mercadier, C., 1999. Integrated 3-D reservoir modeling based on 3-D seismic: the tertiary Malampaya and Camago buildups, offshore Palawan, Philippines. AAPG Bull. 83, 1703–1727. Halfar, J., Mutti, M., 2005. Global dominance of coralline red-algal facies: a response to Miocene oceanographic events. Geology 33, 481–484. http://dx.doi.org/10.1130/ G21462.1. Hallock, P., 1984. Distribution of larger foraminiferal assemblages on two Pacific coral reefs. J. Foraminifer. Res. 11, 195–208. Hallock, P., 1999. Symbiont-bearing Foraminifera. In: Sen Gupta, B.K. (Ed.), Modern Foraminifera. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp. 123–139. Hallock, P., 2005. Global change and modern coral reefs: new opportunities to understand shallow-water carbonate depositional processes. Sed. Geol. 175, 19–33. http://dx.doi. org/10.1016/j.sedgeo.2004.12.027. Hallock, P., Glenn, E.C., 1986. Larger foraminifera: a tool for paleoenvironmental analysis of Cenozoic carbonate depositional facies. Palaios 1, 44–64. http://dx.doi.org/10.2307/ 3514459. Hallock, P., Pomar, L., 2008. Cenozoic evolution of larger benthic foraminifers: paleoceanographic evidence for changing habitats. Proceedings of the 11th International Coral Reef Symposium, Ft. Lauderdale, Florida, pp. 16–20. Hallock, P., Pomar, L., 2009. Cenozoic evolution of larger benthic foraminifers: paleoceanographic evidence for changing habitats. Proceedings of the 11th International Coral Reef Symposium, Ft. Lauderdale, Florida, pp. 16–20. Hallock, P., Schlager, W., 1986. Nutrient excess and the demise of coral reefs and carbonate platforms. Palaios 1, 389–398. Hallock, P., Sheps, K., Chapronière, G., Howell, M., 2006. Larger benthic foraminifers of the Marion Plateau, northeastern Australia (ODP Leg 194): comparison of faunas from bryozoan (Sites 1193 and 1194) and red algal (Sites 1196–1198) dominated carbonate platforms. In: Anselmetti, F.S., Isern, A.R., Blum, P., Betzler, C. (Eds.), Proc. ODP, Sci. Results, pp. 1–31. Hearn, C., Atkinson, M., Falter, J., 2001. A physical derivation of nutrient-uptake rates in coral reefs: effects of roughness and waves. Coral Reefs 20 (4), 347–356. http://dx. doi.org/10.1007/s00338-001-0185-6. Hohenegger, J., 2005. Estimation of environmental paleogradient values based on presence/absence data: a case study using benthic foraminifera for paleodepth estimation. Palaeogeogr. Palaeoclimatol. Palaeoecol. 217, 115–130. http://dx.doi.org/10. 1016/j.palaeo.2004.11.020. Höntzsch, S., Scheibner, C., Brock, J.P., Kuss, J., 2013. Circum-Tethyan carbonate platform evolution during the Palaeogene: the Prebetic platform as a test for climatically controlled facies shifts. Turk. J. Earth Sci. 22, 891–918. http://dx.doi.org/10.3906/yer-1207-8. Hottinger, L., 1997. Shallow benthic foraminiferal assemblages as signals for depth of their deposition and their limitations. Bull. Soc. Géol. de France 168 (4), 491–505.

131

Huston, M., 1985. Variations in coral growth with depth at Discovery Bay, Jamaica. Coral Reefs 4, 19–25. Immenhauser, A., 2009. Estimating palaeo-water depth from the physical rock record. Earth Sci. Rev. 96, 107–139. http://dx.doi.org/10.1016/j.earscirev.2009.06.003. Insalaco, E., 1998. The descriptive nomenclature and classification of growth fabrics in fossil scleractinian reefs. Sediment. Geol. 118, 159–186. http://dx.doi.org/10.1016/ S0037-0738(98)00011-6. James, N.P., 1983. Reef environment. In: Scholle, P.A., Bebout, D.G., Moore, C.H. (Eds.), Carbonate Depositional Environments. American Association of Petroleum Geologists Memoir, 33, pp. 345–440 (Tulsa, OK). Kahng, S.E., Garcia-Sais, J.R., Spalding, H.L., Brokovich, E., Wagner, D., Weil, E., Hinderstein, L., Toonen, R.J., 2010. Community ecology of mesophotic coral reef ecosystems. Coral Reefs 29, 255–275. http://dx.doi.org/10.1007/s00338-010-0593-6. Kanwisher, J.W., Wainwright, S.A., 1967. Oxygen balance in some reef corals. Biol. Bull. 133, 378–390 (http://www.jstor.org/stable/1539833). Langer, M., 1993. Epiphytic foraminifera. Mar. Micropaleontol. 20, 235–265. Largaiolli, T., Mozzi, G., Nardin, M., Rossi, D., 1966. Geologia della zona tra Otranto e S. Cesarea Terme (Prov. di Lecce). Mem. Mus. Civ. St. Nat. Verona 14, 409–413. Leichter, J.J., Wing, S.R., Miller, S.L., Denny, M.W., 1996. Pulsed delivery of subthermocline water to Conch Reef (Florida Keys) by internal tidal bores. Limnol. Oceanogr. 41, 1490–1501. Leichter, J.J., Shellenbarger, G., Genovese, S.J., Wing, S.R., 1998. Breaking internal waves on a Florida (USA) coral reef: a plankton pump at work? Mar. Ecol. Prog. Ser. 166, 83–97. Leichter, J.J., Stewart, H.L., Miller, S.L., 2003. Episodic nutrient transport to Florida coral reefs. Limnol. Oceanogr. 48, 1394–1407. Leichter, J.J., Deane, G.B., Stokes, M.D., 2005. Spatial and temporal variability of internal wave forcing on a coral reef. J. Phys. Oceanogr. 35, 1945–1962. Lim, K., Ivey, G.N., Jones, N.L., 2010. Experiments on the generation of internal waves over continental shelf topography. J. Fluid Mech. 663, 385–400 (http://www.jstor.org/ stable/1539833). Lomando, A.J., Chimney, P.J., Popek, J., 1995. Trap and seal analysis in carbonate shelf margin stratigraphic trap exploration; example from the Lower Miocene Zhujiang Formation, Pearl River Mouth Basin, People's Republic of China. AAPG Bull. 79, 1232. Lowenstam, H.A., 1950. Niagaran reefs of the Great Lake area. J. Geol. 58, 430–488. Lucia, J., 1995. Rock-fabric/petrophysical classification of carbonate pore space for reservoir characterization. AAPG Bull. 79, 1275–1300. http://dx.doi.org/10.1306/ 7834D4A4-1721-11D7-8645000102C1865D. Manker, J.P., Carter, B.D., 1987. Paleoecology and paleogeography of an extensive rhodolith facies from the lower Oligocene of south Georgia and north Florida. Palaios 592, 181–188 (http://www.jstor.org/stable/3514647). Margiotta, S., Ricchetti, G., 2002. Stratigrafia dei depositi oligomiocenici del Salento (Puglia). Boll. Soc. Geol. Ital. 121, 243–252. Mateu-Vicens, G., Hallock, P., Brandano, M., 2008a. A depositional model and paleoecological reconstruction of the lower Tortonian distally steepened ramp of Menorca (Balearic Islands, Spain). Palaios 23, 465–481. http://dx.doi.org/10.2110/palo.2007.p07-061r. Mateu-Vicens, G., Pomar, L., Tropeano, M., 2008b. Architectural complexity of a carbonate transgressive systems tract induced by basement physiography. Sedimentology 55, 1815–1848. http://dx.doi.org/10.1111/j.1365-3091.2008.00968.x. Mateu-Vicens, G., Hallock, P., Brandano, M., 2009. Test-shape variability of Amphistegina d'Orbigny, 1826 as a paleobathymetric proxy: application to two Miocene examples. In: Demchuk, T., Gary, A. (Eds.), Geologic Problem Solving with Microfossils: A Volume in Honor of Garry D. Jones. SEPM Special Publication, pp. 67–82. Mateu-Vicens, G., Box, A., Deudero, S., Rodríguez, B., 2010. Comparative analysis of epiphytic foraminifera in sediments colonized by seagrass Posidonia oceanica and invasive macroalgae Caulerpa spp. J. Foraminifer. Res. 40, 134–147. http://dx.doi.org/10. 2113/gsjfr.40.2.134. Miller, K.G., Fairbanks, R.G., Mountain, G.S., 1987. Tertiary oxygen isotope synthesis, sea level history, and continental margin erosion. Paleoceanography 2, 1–19. http://dx. doi.org/10.1029/PA002i001p00001. Morsilli, M., Bosellini, F.R., Pomar, L., Hallock, P., Papazzoni, C.A., Aurell, M., 2012. Mesophotic coral buildups in a prodelta setting (Late Eocene, southern Pyrenees, Spain): a mixed carbonate siliciclastic system. Sedimentology 59, 766–794. http://dx.doi.org/10.1111/ j.1365-3091.2011.01275.x. Nardin, M., Rossi, D., 1966. Condizioni strutturali della zona compresa nel Foglio Otranto (Provincia di Lecce). Memorie Museo Civico di Storia Naturale Verona 14, 415–430. Nebelsick, J.H., Bassi, D., Drobne, K., 2000. Microfacies analysis and palaeoenvironmental interpretation of Lower Oligocene, shallow-water carbonates (Gornji Grad Beds, Slovenia). Facies 43, 157–176. http://dx.doi.org/10.1007/BF02536989. Nebelsick, J., Stingl, V., Rasser, M., 2001. Autochthonous facies and allochthonous debris flows compared: Early oligocene carbonate facies patterns of the Lower Inn Valley (Tyrol, Austria). Facies 44 (1), 31–46. http://dx.doi.org/10.1007/bf02668165. Nishimura, A., 1992. Carbonate bioclasts of shallow-water origin at Site 793. In: Taylor, B., Fujioka, K., et al. (Eds.), Proceedings of the Ocean Drilling Program, Scientific Results. Ocean Drilling Program, College Station, Texas, pp. 231–234. Noad, J., 2001. The Gomantong Limestone of eastern Borneo: a sedimentological comparison with the near-contemporaneous Luconia Province. Palaeogeogr. Palaeoclimatol. Palaeoecol. 175, 273–302. http://dx.doi.org/10.1016/S0031-0182(01)00376-5. Parente, M., 1994. A revised stratigraphy of the Upper Cretaceous to Oligocene units from southeastern Salento (Apulia, southern Italy). Boll. Soc. Paleontol. Ital. 33, 155–170. Pedley, M., 1998. A review of sediment distributions and processes in Oligo-Miocene ramps of southern Italy and Malta (Mediterranean divide). In: Wright, V.P., Burchette, T.P. (Eds.), Carbonate Ramps. Geological Society Special Publication, London, pp. 163–179. http://dx.doi.org/10.1144/GSL.SP.1999.149.01.09. Perrin, C., 2002. Tertiary: the emergence of modern reef ecosystems. In: Kiessling, W., Flügel, E., Golonka, J. (Eds.), Phanerozoic Reef Patterns. SEPM Special Publication, 72, pp. 587–621.

132

L. Pomar et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 404 (2014) 109–132

Perrin, C., Bosellini, F.R., 2012. Paleobiogeography of scleractinian reef corals: changing patterns during the Oligocene–Miocene climatic transition in the Mediterranean. Earth Sci. Rev. 111, 1–24. http://dx.doi.org/10.1016/j.earscirev.2011.12.007. Perrin, C., Kiessling, W., 2012. Latitudinal trends in Cenozoic reef patterns and their relationship to climate. In: Mutti, M., Piller, W., Betzler, C. (Eds.), Carbonate Systems during the Oligocene–Miocene Climatic Transition. Wiley-Blackwell, Oxford, UK, pp. 17–34. http://dx.doi.org/10.1002/9781118398364.ch2. Peters, S.E., Loss, D.P., 2012. Storm and fair-weather wave base: a relevant distinction? Geology 40 (6), 511–514. http://dx.doi.org/10.1130/g32791.1. Pieri, P., Festa, V., Moretti, M., Tropeano, M., 1997. Quaternary tectonic activity of the Murge area (Apulian foreland — Southern Italy). Ann. Geofis. 15, 1395–1404. Pinto, J., Ortega, S., Marín, Z., Berrios, I., Pérez, A., Pirela, M., 2011. Controls on the newlydiscovered gas accumulations in the Miocene “Perla” carbonate bank, Gulf of Venezuela: a preliminary assessment. SPE-WVS-036 pp. 1–4. Pochon, X., Montoya-Burgos, J.I., Stadelmann, B., Pawlowski, J., 2006. Molecular phylogeny, evolutionary rates, and divergence timing of the symbiotic dinoflagellate genus Symbiodinium. Mol. Phylogenet. Evol. 38, 20–30. http://dx.doi.org/10.1016/j.ympev. 2005.04.028. Pomar, L., Hallock, P., 2007. Changes in coral-reef structure through the Miocene in the Mediterranean: adaptative vs. environmental influence. Geology 35, 899–902. http://dx.doi.org/10.1130/G24034A.1. Pomar, L., Hallock, P., 2008. Carbonate factories: a conundrum in sedimentary geology. Earth Sci. Rev. 87, 134–169. http://dx.doi.org/10.1016/j.earscirev.2007.12.002. Pomar, L., Obrador, A., Westphal, H., 2002. Sub-wavebase cross-bedded grainstones on a distally steepened carbonate ramp, upper Miocene, Menorca, Spain. Sedimentology 49, 139–169. http://dx.doi.org/10.1046/j.1365-3091.2002.00436.x. Pomar, L., Morsilli, M., Hallock, P., Bádenas, B., 2012. Internal waves, an under-explored source of turbulence events in the sedimentary record. Earth Sci. Rev. 111, 56–81. http://dx.doi.org/10.1016/j.earscirev.2011.12.005. Purkis, S.J., Riegl, B., 2005. Spatial and temporal dynamics of Arabian Gulf coral assemblages quantified from remote-sensing and in situ monitoring data. Mar. Ecol. Prog. Ser. 287, 99–113. Rasser, M., Piller, W., 2004. Crustose algal frameworks from the Eocene Alpine foreland. Palaeogeogr. Palaeoclimatol. Palaeoecol. 206, 21–39. http://dx.doi.org/10.1016/j. palaeo.2003.12.018. Reuter, M., Piller, W.E., Harzhauser, M., Kroh, A., Rögl, F., Coric, S., 2011. The Quilon Limestone, Kerala Basin, India: an archive for Miocene Indo-Pacific seagrass beds. Lethaia 44, 76–86. http://dx.doi.org/10.1111/j.1502-3931.2010.00226.x. Ribbe, J., Holloway, P.E., 2001. A model of suspended sediment transport by internal tides. Cont. Shelf Res. 21 (4), 395–422. http://dx.doi.org/10.1016/S0278-4343(00)00081-9. Ribes, T., Salvadó, H., Romero, J., Gracia, M.P., 2000. Foraminiferal colonization on artificial seagrass leaves. J. Foraminifer. Res. 192–201. http://dx.doi.org/10.2113/0300192. Ribes, M., Coma, R., Atkinson, M.J., Kinzie, R.A., 2003. Particle removal by coral reef communities: picoplankton is a major source of nitrogen. Mar. Ecol. Prog. Ser. 257, 13–23. http://dx.doi.org/10.3354/meps257013. Riding, R., 2002. Structure and composition of organic reef and carbonate mud mounds: concepts and categories. Earth Sci. Rev. 58, 163–231. http://dx.doi.org/10.1016/ S0012-8252(01)00089-7 (37 Figs.). Rossi, D., 1969. Foglio 215 “Otranto”. Note Illustrative della Carta Geologica d'Italia. Serv. Geol. Italia, 31 pp. Saller, A.H., Vijaya, S., 2002. Depositional and diagenetic history of the Kerendan carbonate platform, Oligocene, Central Kalimantan, Indonesia. J. Pet. Geol. 25, 123–150. http://dx.doi.org/10.1111/j.1747-5457.2002.tb00001.x. Sandstrom, H., Elliott, J.A., 1984. Internal tidae and solitons on the Scotian shelf: A nutrient pump at work. J. Geophys. Res. 89, 6415–6426. Sattler, U., Immenhauser, A., Schlager, W., Zampetti, V., 2009. Drowning history of a Miocene carbonate platform (Zhujiang Formation, South China Sea). Sediment. Geol. 219, 318–331. http://dx.doi.org/10.1016/j.sedgeo.2009.06.001.

Schlager, W., 2000. Sedimentation rates and growth potential of tropical, cool water and mud mound carbonate factories. In: Insalaco, E., Skelton, P.W., Palmer, T.J. (Eds.), Carbonate Platform Systems: Components and Interactions. Geol Soc Lond, Spec. Publ., 178, pp. 217–227. http://dx.doi.org/10.1144/GSL.SP.2000.178.01.14. Schlager, W., 2003. Benthic carbonate factories of the Phanerozoic. Int. J. Earth Sci. (Geol. Rundsch.) 92, 445–464. http://dx.doi.org/10.1007/s00531-003-0327-x. Schlager, W., Purkis, S.J., 2013. Bucket structure in carbonate accumulations of the Maldive, Chagos and Laccadive archipelagos. Int. J. Earth Sci. 102, 2225–2238. http://dx.doi.org/10.1007/s00531-013-0913-5. Scoffin, T.P., 1970. The trapping and binding of subtidal carbonate sediments by marine vegetation in Bimini lagoon, Bahamas. J. Sediment. Res. 40 (1), 249–273. http://dx. doi.org/10.1306/74d71f28-2b21-11d7-8648000102c1865d. Scoffin, T.P., 1972. Fossilization of Bermudan patch reefs. Science 178, 1280–1282. Seilacher, A., Aigner, T., 1991. Storm deposition at the bed, facies, and basin scale: the geologic perspective. In: Einsele, G., Ricken, W., Seilacher, A. (Eds.), Cycles and Events in Stratigraphy. Springer-Verlag, Berlin, pp. 249–267. Sen Gupta, B.K., 1999. Foraminifera in marginal marine environments. In: Sen Gupta, B.K. (Ed.), Modern Foraminifera. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp. 141–160. Serra-Kiel, J., Hottinger, L., Caus, E., Drobne, K., Ferrandez, C., Kumar Jauhri, A., Less, G., Pavlovec, R., Pignatti, J., Samso, J.M., Schaub, H., Sirel, E., Strougo, A., Tambareau, Y., Tosquella, J., Zakrevskaya, E., 1998. Larger foraminiferal biostratigraphy of the Tethyan Paleocene and Eocene. Bull. Soc. Géol. France 169, 281–299. Smith, J.E., Smith, C.M., Vroom, P.S., Beach, K.L., Miller, S.L., 2004. Nutrient and growth dynamics of Halimeda tuna on Conch Reef, Florida Keys: Possible influence of internal tides on nutrient status and physiology. Limnol. Oceanogr. 49, 1923–1936. Southard, J.B., Cacchione, D.A., 1972. Experiments on bottom sediment movement by breaking internal waves. In: Swift, D.J., Duane, D.B., Pilkey, O.H. (Eds.), Shelf Sediment Transport: Process and Pattern. Dowden, Hutchinson & Ross, Stroudsburg, Pa., pp. 83–97. Thorpe, S.A., 1999. The generation of alongslope currents by breaking internal waves. J. Phys. Oceanogr. 29, 29–38. Thorpe, S.A., 2005. The Turbulent Ocean. Cambridge University Press, Cambridge (447 pp.). Tucker, M.E., Wright, V.P., 1990. Carbonate Sedimentology. Blackwell Sci. Public (462 pp.). Van Buchem, F.S.P., Allan, T.L., Laursen, G.V., Lotfpour, M., Moallemi, A., Monibi, S., Motiei, H., Pickard, N.A.H., Tahmasbi, A.R., Vedrenne, V., Vincent, B., 2010. Regional stratigraphic architecture and reservoir types of the Oligo-Miocene deposits in the Dezful Embayment (Asmari and Pabdeh Formations) SW Iran. In: Van Buchem, F.S.P., Gerdes, K.D., Esteban, M. (Eds.), Mesozoic and Cenozoic Carbonate Systems of the Mediterranean and the Middle East: Stratigraphic and Diagenetic Reference Models. Geological Society, London, Special Publications, 329, pp. 219–263. http://dx.doi. org/10.1144/sp329.10. Vandenberghe, N., Hilgen, F.J., Speijer, R.P., Ogg, J.G., Gradstein, F.M., Hammer, O., Hollis, C. J., Hooker, J.J., 2012. Chapter 28 - The Paleogene Period. In: Gradstein, F.M., Ogg, J.G., Schmitz, M., Ogg, G. (Eds.), The Geologic Time Scale. Elsevier, Boston, pp. 855–921. http://dx.doi.org/10.1016/B978-0-444-59425-9.00028-7. Vaziri-Moghaddam, H., Kimiagari, M., Taheri, A., 2006. Depositional environment and sequence stratigraphy of the Oligo-Miocene Asmari Formation in SW Iran. Facies 52, 41–51. http://dx.doi.org/10.1007/s10347-005-0018-0. Vaziri-Moghaddam, H., Seyrafian, A., Taheri, A., Motiei, H., 2010. Oligocene–Miocene ramp system (Asmari Formation) in the NW of the Zagros basin, Iran: microfacies, paleoenvironment and depositional sequence. Rev. Mex. Cienc. Geol. 27, 56–71. Wray, J.L., 1977. Calcareous Algae. Elsevier, Amsterdam (185 pp.). Zachos, J., Pagani, M., Sloan, L., Thomas, E., Billups, K., 2001. Trends, rhythms, and aberrations in global climate 65 Ma to present. Science 292, 686–693. http://dx.doi.org/10. 1126/science.1059412. Zicanov, O., Slinn, D.N., 2001. Along-slope current generation by obliquely incident internal waves. J. Fluid Mech. 445, 235–261. http://dx.doi.org/10.1017/S0022112001005560.