Palynological investigation of Holocene palaeoenvironmental changes in the coastal plain of Marathon (Attica, Greece)

Palynological investigation of Holocene palaeoenvironmental changes in the coastal plain of Marathon (Attica, Greece)

Geobios 42 (2009) 43–51 Original article Palynological investigation of Holocene palaeoenvironmental changes in the coastal plain of Marathon (Attic...

543KB Sizes 0 Downloads 32 Views

Geobios 42 (2009) 43–51

Original article

Palynological investigation of Holocene palaeoenvironmental changes in the coastal plain of Marathon (Attica, Greece)§ Investigation palynologique des changements pale´oenvironnementaux holoce`nes de la plaine coˆtie`re du Marathon (Attica, Gre`ce) Katerina Kouli a,*, Maria Triantaphyllou a, Kosmas Pavlopoulos b, Theodora Tsourou a, Panagiotis Karkanas c, Michael D. Dermitzakis a a

Department of Historical Geology-Palaeontology, University of Athens, Panepistimiopolis, 15784 Greece b Faculty of Geography, Harokopio University, 70 El Venizelou Avenue, 17671 Athens, Greece c Ephoreia of Palaeoanthropology-Speleology, 34b Arditou street, 11636 Athens, Greece Received 23 October 2007; accepted 26 July 2008 Available online 9 October 2008

Abstract The identification of Middle-Late Holocene palaeoenvironmental conditions of the Marathon coastal plain gained great interest in the last decades due to its high environmental and archaeological importance. Palynological analysis of samples from two boreholes and two trenches along a transect in the marshy area of the Marathon coastal plain, enabled the tracing of the vegetation and the main environmental changes for the last 6000 cal BP. Pollen data suggest a human disturbed environment with Pinus, Quercus, Juniperus and Ericaceae, while a general trend towards Mediterranean vegetation patterns is observed during the last 3000 cal BP. Pollen grains from aquatic and hydrophilous plants, dinoflagellate cysts, algal remains and other palynomorphs were used in order to determine the local depositional environment and its evolution through time. # 2008 Elsevier Masson SAS. All rights reserved. Résumé L’identification des conditions paléoenvironnementales de l’Holocène moyen-supérieur de la plaine côtière de Marathon a gagné un grand intérêt durant les dernières décennies, de part son importance environnementale et archéologique. Les analyses palynologiques des échantillons provenant de deux forages et deux fossés situés dans le secteur marécageux de la plaine côtière de Marathon, ont permis le traçage de la végétation et des changements environnementaux principaux durant les derniers 6000 cal BP. Les analyses polliniques suggèrent l’influence humaine sur une végétation dominée par Pinus, Quercus, Juniperus et les Ericaceae. Une tendance générale vers une végétation méditerranéenne est plus visible pendant les derniers 3000 cal BP. Les grains de pollen des plantes aquatiques et hydrophiles, kystes de dinoflagellés, résidus d’algues et autres palynomorphes ont été utilisés pour déterminer les caractéristiques du milieu de dépôt local et son évolution dans le temps. # 2008 Elsevier Masson SAS. All rights reserved. Keywords: Pollen analysis; Vegetation history; Palaeoecology; Holocene; Greece Mots clés : Analyse pollinique ; Histoire de la végétation ; Paléoécologie ; Holocène ; Grèce

1. Introduction

§

Corresponding editor: Serge Legendre. * Corresponding author. E-mail address: [email protected] (K. Kouli).

The Marathon coastal plain has been continuously inhabited since the Neolithic (Pantelidou-Gofas, 1997) and has a great historical as well as archaeological significance. During the 6th century BC, the four flourishing communities of the area were

0016-6995/$ – see front matter # 2008 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.geobios.2008.07.004

44

K. Kouli et al. / Geobios 42 (2009) 43–51

integrated into Tetrapolis, one of the twelve districts (deme) into which Attica was divided before the time of Theseus (Petrakos, 1995). The area is famous for the ancient battle of 490 BC between the Athenians and the Persians and, based on this, was proclaimed a national park. For the 2004 Olympic Games in Athens, a rowing center was constructed at this place. Given the great environmental and archaeological importance of the area, the investigation of its palaeoenvironmental conditions during the Holocene becomes very interesting. Sedimentological, micromorphological and micropalaeontological analysis together with radiocarbon dating of the sediments determined the depositional environments and the sea level changes recorded in the area for the last 6,000 cal BP (Pavlopoulos et al., 2003; Triantaphyllou et al., 2003). However, relatively little is known about Holocene palaeovegetation of this area. The only published pollen record in Attica comes from the archaeological deposits of the cave of Kitsos in Lavrio (Renault-Miskovsky, 1981) since all other pollen sites are found at a distance of several kilometers in neibour basins, like Kopais (Turner and Greig, 1975; Allen, 1990), Megaris (Jahns, 2003) and in Peloponnese (Aliki: Kontopoulos and Avramidis, 2003; Lerna: Jahns, 1993; Nemea: Atherden et al., 1993; Koiladha: Bottema, 1990). This study investigates the potential of palynodata in recording the local microenvironmental changes in the coastal plain of Marathon, comparing them with the existing micropalaeontological and sedimentological results (Pavlopoulos et al., 2003, 2006; Triantaphyllou et al., 2003) and aims to contribute to our knowledge on Holocene vegetation of Attica. 2. Site setting The NE-SW elongated Marathon coastal plain is located in the NE Attica, eastern Greece (Fig. 1). The broader area consists of ‘‘NE Attica’’ geotectonic units, that represent a

Fig. 1. Topographic map of the Marathon coastal plain showing the locations of cores 6 and 7 and trenches 4 and 10. Carte topographique de la plaine côtière de Marathon avec la localisation des forages 6 et 7 et des fosses 4 et 10.

‘‘relatively autochtonous’’ metamorphic sequence (Lozios, 1993). The Holocene is represented by various types of alluvial deposits, formed mainly by the Inois River and other small torrents. The area has been affected by two main fault systems, the older one having a NE-SW direction and the younger one having a NW-SE direction (Lozios, 1993). An apparent coastal stability has been evidenced at least for the last 5000 yr (Kraft, 1972; Pavlopoulos et al., 2006). The plain is divided into two parts by the Inois River channel. In the southwest of the deltaic fan of the Inois River (Kainourgio Rema), there was a marshy area (Vreksisa) that was drained some decades ago. The large marsh of Marathon (also known as the Great Marsh) extends to the east, separated from the sea by a barrier beach with low sand dunes (Baeteman, 1985). The Marathon plain resembles the typical coastal plains of Greece in morphology (Kraft et al., 1975, 1977; Fouache, 1999). The plain coastline is almost straight, with the exception of a ledge formed near the recent river mouth, not affected by tides (tide amplitude less than 20 cm). No significant changes have been observed on the coastline limit between 1889 and 1938. The area near the mouth of Kenourio Rema was retreating at a rate of about 2 m/yr in the 1950’s and 1960’s, slowing down to 1 m/yr in the last two decades (Maroukian et al., 1993). The climate is typical Mediterranean with warm, dry summers and mild, humid winters. Mean annual precipitation for the meteorological station of Marathon is 567 mm and mean air humidity is 59–64%. Monthly air temperature ranges between 27 and 10 8C with a mean annual value of 18 8C. About 50 cloudy days each year are recorded for the area and the mean sunlight is 2920 h per year. Sea surface temperature fluctuates between 10.3 and 26.7 8C. The history of the fertile land of Marathon coastal plain goes back to the Neolithic, when the first important human inhabitations in Nea Makri (Pantelidou-Gofas, 1991, 1995), Vreksisa, Plasi, Kato Souli and in Panos cave of Oenoe is recorded (Petrakos, 1995; Pantelidou-Gofas, 1997). The older so far known Bronze Age cemetery has been discovered in the area (Pantelidou-Gofas, 2005). During the Geometric times, four inhabitation centers existed in the plain of Marathon: Marathon, Provalinthus, Tricorythus and Oinoe. In the 6th century BC, they were incorporated into Tetrapolis (Petrakos, 1995). The area is famous from the ancient battle of 490 BC between the Athenians and the Persians in which the heavily outnumbered Athenian army defeated the Persians. A burial mound (tymbos) for the dead Athenian soldiers was erected near the battlefield. Tymbos nowadays is marked by a marble memorial stele and surrounded by a park. Three main villages, Kato Souli, Marathon and Nea Makri, exist in the area today. In the area of the drained Great Marsh, many summer houses are built during the last decades and a rowing center was constructed for the 2004 Olympic Games in Athens. The plain is widely cultivated, being one of the main vegetable producer areas in Attica. The vegetation of the marshy area consists mainly of Phragmites, Typha latifolia and Juncus maritime. Along the streams some Platanus orientalis, Populus alba and Salix alba are found. Parallel to the seashore,

K. Kouli et al. / Geobios 42 (2009) 43–51

a natural forest of Pinus pinea exists were Pinus halepensis, Juniperus phoenica, Quercus ilex and Quercus coccifera are also found. The hilly rocky areas around the plain are covered with maquis vegetation mainly represented by Juniperus phoenicea, Pistacia lentiscus, P. terebinthus, Ceratonia siliqua, Olea europaea, Ephedra foemina, Quercus coccifera, Rhamnus alaternus, Calicotome villosa and Prunus webbii. Further inland and in the fields’ margins, small traces of the natural woodland vegetation are evidences consisting of rare trees of Quercus ilex, Quercus pubescens, Phillerea latifolia and Myrtus communis. 3. Depositional environment and age assessment Baeteman (1985) conducted a systematic drill-hole study for the area and presented detailed information on the stratigraphic sequence of the plain. Triantaphyllou et al. (2003) investigated the microfauna recovered from the deposits and determined three distinct biofacies based on foraminifera and ostracoda assemblages: the shallow mesohaline-oligohaline biofacies, indicative of low march environments approximately at the mean sea level (Petrucci et al., 1983), the shallow oligohaline-fresh waters biofacies indicative of high-middle marsh environments (Scott et al., 1979) suggesting an approximate elevation of 20 cm above mean sea level and finally the mesohaline-oligohaline to oligohaline-freshwater biofacies characteristic of an intermediate mesohaline-oligohaline to oligohaline-freshwater lagoonal environment. Pavlopoulos et al. (2003, 2006) determined the sequence of depositional environments and the sea level changes recorded in the area for about the last 6000 yr, using micromorphological and micropalaeontological methods in addition to AMS radiocarbon datings (Table 1). Three sedimentary units, namely

45

A, B and C, were recognized after grouping the sedimentary facies characteristics (Fig. 2). Sedimentary unit A consists of fossiliferous bioturbated lagoonal mud predominating in the central part of the embayment, with peloidal charophytic mud prevailing in the lower parts of the unit. Three peat layers are included in unit A. The lower one (peat 1), dated at approximately 5500 cal BP (Pavlopoulos et al., 2006), starts as laminated algal peat in the lower horizons and changes to a reed swamp peat. The other two peats found in unit A (peat 2 dated to about 4700 cal BP and peat 3 dated to about 3800 cal BP; Pavlopoulos et al., 2006) are composed of almost pure plant remains. Depositional environment of unit A is a typical mesohaline-oligohaline lagoon with an embayment depth never exceeding a few meters (Triantaphyllou et al., 2003; Pavlopoulos et al., 2006). Unit B consists of mixed carbonate and siliciclastic mud accompanied by high amounts of fragmented plant material. At the boundary of units A and B, the presence of mollusc shells provided a radiocarbon age of about 3500 cal BP, while the presence of wood fragments in the upper horizons of sedimentary Unit B provided a radiocarbon age of about 2500 cal BP (Pavlopoulos et al., 2006), close to the time that the Marathon Battle took place (490 BC). Deposits of Unit B represent a freshwater to oligohaline-mesohaline mixture of windblown or riverside silts and clays and palustrine lime mud. Communication with the sea was frequent but not perennial (Triantaphyllou et al., 2003). Deposits of the uppermost sedimentary unit C vary locally, representing a mixture of fluviatile and palustrine environments (Pavlopoulos et al., 2006). In the area of the former nearshore environment, the deposits consist of well-sorted weakly cemented sands and silty sands, while, towards the centre of the embayment, palustrine mud is sometimes interrupted by layers of well sorted sands. Palustrine deposits include two thin

Table 1 Radiocarbon dating for the Marathon coastal plain deposits (from Pavlopoulos et al., 2006) Datations radiocarbones des de´poˆts se´dimentaires de la plaine coˆtie`re de Marathon (d’apre`s Pavlopoulos et al., 2006). Laboratory code

Trench/ Borehole Noa

Unit

Absolute altitude (m)b

Material

14 C Age (yr BP)

d13C PDB (%)

Calibrated Age

Age (BC)

Hv 8546a GX-27909 (AMS) GX-27908 (AMS) Hv 8547a GX-27915 Hv 8533a Hv 8551a Hv 8548a GX-27910 GX-27911 GX-27914 Hv 8552a GX-27913 GX-27912 (AMS) Hv 8549a Hv 8550a

6–7 a 1 1 6–7 a 4 6a 37 a 36 a 6 6 7 37 a 6 6 36 a 36 a

C C C C A-/B A A A A A A A A A A A

+0.10 +1.20 +1.00 0.10 1.80 +0.30 to 0.50 0.80 to 1.20 1.95 to 1.85 1.47 1.65 2.20 2.10 to 2.20 2.13 2.13 2.15 to 2.25 2.35 2.45

Peat 5 Wood fragment Wood fragments Peat 4 Shells (brackish) Carbonate mud Carbonate mud Carbonate mud Peat 3, top Peat 3, middle Peat 2, top Peat 1, mean Peat 1, top Peat 1, wood fragment Peat 1, middle to top Peat 1, base

1360  40 2400  30 2410  40 2480  60 3570  180 4020  60 3985  65 3550  80 3560  60 3540  70 4160  60 4575  60 4770  60 5080  40 4869  75 4570  105

n.r. 25.2 27.6 n.r. 4.5 n.r. n.r. n.r. 27.4 28.6 27.2 n.r. 27.4 24.1 n.r. n.r.

1309–1194 2465–2351 2693–2351 2711–2467 3684–3243c 4115–3945c 4070–3894c 3529–3348c 3959–3725 3898–3701 4824–4588 5445–5053 5590–5334 5894–5751 5707–5486 5449–5048

641–756 AD 516–402 744–402 762–518 1735–1294c 2166–1996c 2121–1945c 1570–1339c 2010–1776 1949–1752 2875–2639 3496–3104 3541–3385 3945–3802 3758–3557 3500–3099

a b c

Radiocarbon dates from Baeteman (1985). Absolute altitudes are corrected based on new map data of present work (with a  20 cm uncertainty). Corrected for reservoir effect.

46

K. Kouli et al. / Geobios 42 (2009) 43–51

Fig. 2. Trenches and cores logs and position of the analyzed samples (from Pavlopoulos et al., 2006, modified). (1) artificial fill, (2) topsoil, (3) sand, (4) sand with gravels and pebbles, (5) silt, (6) clay, (7) silty sand, (8) sandy silt, (9) clayey silt, (10) sandy clay, (11) silty clay, (12) sandy clay with subrounded gravels, (13) palustrine mud, (14) lagoonal mud, (15) peloidal algal mud, (16) mudcracs, (17) rootlets, (18) charophytes, (19) pellets, (20) fossils, (21) bioturbation, (22) peat, (23) algal peat, (24) hard horizon. Peat ages are in cal BP. * Age according to Baeteman (1985). Logs des forages et fosses et position des échantillons analysés (modifiée d’après Pavlopoulos et al., 2006). (1) remplissage artificiel, (2) sol, (3) sable, (4) sable avec graviers et galets, (5) limon, (6) argile, (7) sable limoneux, (8) limon sableux, (9) limon argileux, (10) argile sableuse, (11) argile limoneuse, (12) argile sableuse avec graviers, (13) boue palustre, (14) boue lacustre, (15) boue algaire pelloïdale, (16) fente de dessiccation, (17) petites racines, (18) charophytes, (19) grains, (20) fossiles, (21) bioturbation, (22) tourbe, (23) tourbe algaire, (24) tourbe. Âge en cal BP. * Âge en accord avec Baeteman (1985).

K. Kouli et al. / Geobios 42 (2009) 43–51

47

peat layers (peat 4 and 5) dated to about 2590 cal BP and 1250 cal BP respectively (Baeteman, 1985). In the central part of the embayment, an isolated, frequently exposed wetland has been recognized (Triantaphyllou et al., 2003; Pavlopoulos et al., 2006), mainly influenced by fresh water inputs. The whole sedimentary sequence of Marathon coastal plain is a typical progradation sequence with several minor cycles. The sea level rise indicated by the several peat formations (Pavlopoulos et al., 2006) has been estimated to be lower than the one predicted by the glaciohydroisostatic model (Lambeck, 1995, 1996) and the data from other Greek areas (Kraft et al., 1975, 1977; van Andel and Lianos, 1984; Kambouroglou, 1989) that are considered relatively stable. Hence, an average tectonic uplift of the area has been suggested at a rate of about 0.4–0.5 mm/yr, which almost counterbalances the predicted rate of relative sea-level rise of about 0.6–0.7 mm/yr for the last 2000 yr (Pavlopoulos et al., 2003, 2006). This explains also the relative geomorphological stability since at least the Classical times suggested by the historical documents (Kraft, 1972).

was plotted, within which the positively identified evergreen Quercus is indicated. Pollen percentage calculations were based on regional pollen. Aquatic pollen and Cyperaceae were excluded from pollen sum. Palynomorph concentrations were calculated based on their comparison to the introduced Lycopodium spores and expressed as grains/cm3 of dry sediment. Pollen percentage histograms were constructed using the programs TILIA and TGVIEW (Grimm, 1992). The results of palynomorph analysis for each profile are presented as percentage pollen diagrams (Figs. 3–6) in correlation with the recognized sedimentary units for the Marathon coastal plain (Pavlopoulos et al., 2003, 2006). Pollen and spores from aquatic and hydrophilous plants, dinoflagellate cysts, algal and fungal remains as well as other palynomorphs were used to determine various depositional environments of the area and their evolution through time.

4. Material and pollen analytical methods

The main pollen contributors in the pollen flora are Pinus; Quercus, Poaceae, Asteraceae, Juniperus and Ericaceae. The highest pollen concentrations (62,000 grains/cm3) was recorded in trench 10 at 0.95 m and the lowest (500 grains/ cm3) in trench 4 at 1.40 m). The few available pollen spectra recovered from each profile do not allow for interpretations in terms of vegetation evolution but can only provide punctual images of the landscape during short time intervals. Pollen spectra of core 7 (Fig. 3) derive from sedimentary Unit A, with the exception of the upper spectrum coming from sedimentary Unit B. Pollen concentration values range between 10,700 grains/cm3 (at 3.20 m) and 3500 grains/cm3 (at 3.10 m). Core 7 is characterized by high arboreal pollen percentages. Pinus and Quercus prevail in the pollen spectra with percentages around 30 and 15% respectively, while the presence of Ericaceae (10.2%), Juniperus (5.8%), Carpinus/

The material used in the present study comes from 4 (2 boreholes and 2 trenches) out of the 6 profiles realized for the study of Pavlopoulos et al. (2003, 2006) along a transect in the marshy area of the Marathon coastal plain (Fig. 2). A total of 20 samples were available for palynological analysis, out of each about 1 cm3 was chemically treated with HCl (37%), HF (40%), acetolysed and sieved using a 10 mm sieve. Residues were mounted in silicon oil. Pollen and spores were identified using the Moore et al. (1991) key and the Reille (1992–1998) pollen floras, while other non-pollen palynomorph identification was based on the van Geel et al. (1989, 2003) studies. The differentiation of evergreen and deciduous Quercus was not always possible, as many pollen grains were crumbled, so a composite histogram

Fig. 3. Percentage palynological diagram of core 7. Diagramme pollinique en pourcentages du forage 7.

5. Results

48

K. Kouli et al. / Geobios 42 (2009) 43–51

Fig. 4. Percentage palynological diagram of core 6. Diagramme pollinique en pourcentages du forage 6.

Fig. 5. Percentage palynological diagram of trench 4. Diagramme pollinique en pourcentages de la fosse 4.

Fig. 6. Percentage palynological diagram of trench 10. Diagramme pollinique en pourcentages de la fosse 10.

Ostrya type (2.2%) and Sorbus is noteworthy. Herb vegetation is mainly represented by Poaceae (11.4%), Ranunculus acris (7.4%), Asteroideae (2.9%) and Cistaceae. The general image of the pollen flora recovered from core 6 (Fig. 4) exhibits some similarities with core 7. Unfortunately only three levels, two from sedimentary Unit A and one from sedimentary Unit B, were available for pollen analysis. Pollen concentrations are about 4800 grains/cm3.

In trench 4 (Fig. 5), the analyzed levels draw from all recognized sedimentary Units. Pollen concentrations are lower than in core 7, ranging between 8700 grains/cm3 (at 0.76 m) and 500 grains/cm3 (at 1.40 m). Pinus is the dominant arboreal pollen contributor, especially in sedimentary Unit C, where its percentages exceed the 50% of the pollen sum. Ericaceae (3.5%), Juniperus (1.3%), Quercus and Pistacia comprise the rest of the arboreal taxa, while herb vegetation is mainly

K. Kouli et al. / Geobios 42 (2009) 43–51

represented by Poaceae (8.7%), Asteroideae (6.2%), Cichorioideae, Cistaceae and Sanquisorba. Cichorioideae abundance appears higher (about 33.4%) in top two spectra of sedimentary Unit C. Spectra from trench 10 (Fig. 6) exhibit large fluctuations in pollen concentrations ranging between 62,000 grains/cm3 (at 1.00 m) and 2350 grains/cm3 (at 2.30 m). In accordance with trench 4, Pinus is the dominant pollen contributor, while other tree taxa like Carpinus/Ostrya type, and Juniperus exhibit low abundances. Quercus pollen has not been recorded. At the top levels, Chenopodiaceae and Plantago lanceolata display their highest abundances in the Marathon coastal plain pollen spectra (15.1 and 8%, respectively). Cerealia type pollen was encountered in spectra of all profiles, though it appears less abundant in spectra of sedimentary Unit C. The fluctuations of the curves of aquatics – Cyperaceae and Sparganium emersum – are significant, due to the local conditions of each profile. The record of freshwater algae (Spirogyra, Botryococcus) is perpetual, while the marine dinoflagellates (Operculodinium centrocarpum and Spiniferites spp.) are only found up to the middle part of the profiles. Finally, the presence of several fungal and animal remains completes the image of the pollen spectra. 6. Discussion – palaeoenvironmental interpretation We focus the discussion on the Marathon pollen profiles on two main aspects: the delineation of the palaeovegetation of the area and the determination of the local depositional environments related to their evolution through time. The pollen flora recovered, despite the punctual character of the available data, comprises representatives from different phytogeographic zones and provides an image of the landscape for the last 6000 cal BP. Mediterranean vegetation is fairly represented by the occurrence of pollen of evergreen Quercus, Juniperus, Pistacea and by the great variability of herbaceous taxa – e.g. Sanguisorba, Helianthemum, etc. – , while deciduous Quercus and Carpinus/Ostrya-type are the main representatives of the thermophilous deciduous mixed woodlands that was covering the slopes around the coastal plain. The presence of Abies and Fagus pollen is indicative of the altitudinal conifer forests and local beech communities that flourish even today at Parnitha Mountain, about 30 km to the west. The continuous presence of human in the area since the Neolithic (before 6000 BC) (Pantelidou-Gofas, 1995; Petrakos, 1995) and the consequent exploitation of the environment is evidenced in the Marathon coastal plain record. All pollen diagrams are featured by the presence of human indicator species such us Cerealia type, Ranunculus acris, Plantago lanceolata type, Coprophilous sordariaceae spores (van Geel et al., 2003) and Puccinia teleutospores (van Geel et al., 19801981; Carrion and van Geel, 1999), providing clear evidence about cereal cultivation and stock breeding activities in the area. Moreover, the presence of taxa like Ericaceae and Juniperus must have been favored by grazing. Their

49

expansion – together with Pinus abundance – on cleared ground is considered to characterize the human disturbed vegetation in Greece (Bottema, 1974; Bottema and Woldring, 1990; Jahns, 1993). Moreover, the presence of Olea pollen in spectra leaves no doubt about the cultivation of olives in the area, as its pollen is generally considered under-represented in pollen diagrams from Greece (Jahns, 1993). The upper part of the sequence (top of sedimentary unit B and sedimentary unit C; 3000 cal BP to present) is characterized by very high abundances of Pinus in all profiles. The expansion of Pinus pollen after 3000 cal BP has been recorded in several pollen diagrams of southern Greece like Koiladha (Bottema, 1990), lake Lerna (Jahns, 1993) and Kleonai (Atherden et al., 1993) and has been attributed to the spread of pine woods on coastal areas, where they still flourish today (e.g., the wood of Pinus pinea covers most of the present coastline of Marathon bay). The instability of hydrological conditions (shallow waters, periodic sea and fresh water flooding; Pavlopoulos et al., 2003, 2006; Triantaphyllou et al., 2003) seems to control the expansion of the aquatic and hydrophilous vegetation in the area throughout 6000 cal BP. The studied time span is featured by peaks in the Sparganium emersum curve most probably related to the water-table changes. The presence of a shallow aquatic environment is supported by the continuous record of spores of Spirogyra and other Zygnemataceae algae that characterize shallow and stagnant waters (van Geel et al., 1980-1981). Overall, the distribution of aquatic and hydrophilous pollen, algal spores, dinoflagellate cysts, fungal spores and insect and other invertebrate remains in pollen spectra of the coastal plain of Marathon, indicates an ongoing variation of the depositional environment both in time and space. A Q-mode cluster analysis was performed on the complete dataset in order to define areas of similar hydrological conditions (Fig. 7). Cluster I is represented by samples T8/7, T8/5, T10/1, T6/F1, T8/6, T6/P1, T10/3 and T10/4. The vast majority of these samples belong to sedimentary unit C. All clustered samples are related to a very shallow depositional environment (SDE facies) as they are characterized by a high abundance of Spirogyra and other Zygnemataceae spores and type 128. Zygnemataceae are among the most common freshwater algae and indicate shallow and stagnant waters (van Geel et al., 19801981), while type 128 is indicative of shallow and eutrophic water (van Geel et al., 1983). Clusters IIa and IIb are represented by samples T7/1, T10/5, T8/4, T6/P2 and T7/4 and samples T7/9, T8/3, T8/1, T7/2, T7/5, T7/7 and T7/3, respectively. They are associated with a relatively deeper depositional environment (DDE facies), since they are characterized by a lower frequency of Spirogyra and the presence of Botryococcus, Pediastrum and dinoflagellate cysts. More specifically cluster IIa is characterized by the presence of dinoflagellate cysts. The small number of the Operculodinium centrocarpum and Spiniferites spp. cysts indicate that, although there was a periodic sea water input in the lagoon, there was no regular connection with the sea. Dinoflagellate cysts have been used as salinity indicators by several authors (e.g. Wall et al., 1973; Mudie et al., 2001; Head

50

K. Kouli et al. / Geobios 42 (2009) 43–51

Fig. 7. Cluster analysis leading to the description of different depositional environments. Analyse de groupement conduisant à la description des divers environnements de dépôt.

et al., 2005). In order to establish a salinity signal in cyst distributions, Dale (1996) compared the late Quaternary data from the Black Sea with recent observations from Norwegian fjords and the Baltic Sea; he suggested that cyst assemblages that are restricted to the cosmopolitan species O. centrocarpum and Spiniferites spp. are indicative of salinities lower than 7–3%. Cluster IIb is characterized by the total absence of indication of sea water input and the abundance of local vegetation, like Sparganium emersum and Cyperaceae. Both depositional environments recorded by palynomorph analysis in the coastal plain of Marathon (Fig. 7) appear to correlate directly with the biofacies that have been recognized by the micropalaeontological study in the area (Triantaphyllou et al., 2003). In particular, the shallow environments (SDE facies) that characterize a very shallow depositional environment correlates with the oligohaline-fresh water biofacies recorded in sedimentary unit C (2500 cal BP to present). The DDE facies correlates with the mesohaline-oligohaline biofacies recorded in sedimentary Units A and B (before 5800 to 3500 cal BP and 3500–2500 cal BP, respectively). The palynomorph analysis provides further evidences for the Marathon coastal plain being a marshy environment with periodical sea influence between 6000 cal BP to 2500 cal BP. During the last 2500 years, the wetland became shallower and partially desiccated resulting to the restriction of the high-middle marsh conditions to the southern part of the plain. 7. Conclusions The environmental history of the Marathon coastal plain for the Middle-Late Holocene has been recorded in the palynomorphs found in the studied deposits. The palaeovegetation of the area was found to be influenced by humans during the whole period, with the cereal cultivation and the stock breeding being the main anthropic activities. Vegetation patterns show the general trend towards Mediterranean environments for the last 3000 cal BP approximately, in accordance with previous studies in southern Greece (Atherden et al., 1993; Jahns, 1993). Mesohaline-oligohaline biofacies (MO) that have been recognized by the micropalaeontological analysis (Triantaphyllou et al., 2003) correlate with relatively deeper environ-

ments (DDE facies), while the oligohaline-fresh water (OFW) biofacies correlate with very SDE facies. The palaeodata of the Marathon coastal plain show its continuous shift towards the landward area that has been attributed to a slowing down of the sea level rise. In conclusion, the determination of the local depositional environments and their evolution through time by the joined use of micropalaeontological, sedimentological and palynological results appears to be successfully applicable in small coastal basins. Acknowledgments We wish to thank Dr. M. Papanikolaou for her helpful discussion on dinoflagellate cysts and both Dr Alexandra van der Geer and Dr. H. Koufosotiri for their comments and help with the manuscript. An anonymous reviewer is thanked for constructive comments that improved the manuscript. References Allen, H., 1990. A postglacial record from the Kopais basin, Greece. In: Bottema, S., Entjes-Nieborg, G., van Zeist, W. (Eds.),Man’s role in the Shaping of the Eastern Mediterranean landscape. Balkema, Rotterdam, pp. 173–181. Atherden, M., Hall, J., Wright, J.C., 1993. A pollen diagram from the northeast Peloponnese Greece: implications for vegetation history and archaeology. The Holocene 3, 351–356. Baeteman, C., 1985. Late Holocene geology of the Marathon plain (Greece). Journal of Coastal Research 1, 173–185. Bottema, S., 1974. Late Quaternary vegetation history of Northwestern Greece. Ph.D. thesis, Rijksuniversiteit te Groningen (unpublished). Bottema, S., 1990. Holocene environment of the Southern Argolid: a pollen core from Kiladha Bay. In: Wilkinson, T.J., Duhon, S.T. (Eds.), Excavations in Franchthi cave 6. Indiana University Press, Bloomington, pp. 117–138. Bottema, S., Woldring, H., 1990. Anthropogenic indicators in the pollen record of the Eastern Mediterranean. In: Bottema, S., Entjes-Nieborg, G., van Zeist, W. (Eds.), Man’s role in the Shaping of the Eastern Mediterranean landscape. Balkema, Rotterdam, pp. 231–264. Carrion, J.S., van Geel, B., 1999. Fine-resolution Upper Weichselian and Holocene palynological record from Navarrés (Valencia, Spain) and a discussion about factors of Mediterranean forest succession. Review of Palaeobotany and Palynology 106, 209–236. Dale, B., 1996. Dinoflagellate cyst ecology: modeling and geological applications. In: Jansonius, J., McGregor, D.C. (Eds.), Palynology: principles and applications 3. American Association of Stratigraphic Palynologists Foundation, Texas, pp. 1249–1275.

K. Kouli et al. / Geobios 42 (2009) 43–51 Fouache, E., 1999. L’alluvionnement historique en Grèce Occidentale et au Péloponnèse. Bulletin de Correspondance Hellénique, École Française d’Athènes, Supplément 35. Éditions De Boccard, Paris. Grimm, E., 1992. Tilia and Tilia-graph: Pollen spreadsheet and graphics programs. Programs and Abstracts, 8th International Palynological Congress, Aix-en-Provence, 6-12 September 1992, pp. 56. Head, M.J., Seidenkrantz, M.-S., Janczyk-Kopikowa, Z., Marks, L., Gibbard, P.L., 2005. Last Interglacial (Eemian) hydrographic conditions in the southeastern Baltic Sea, NE Europe, based on dinoflagellate cysts. Quaternary International 130, 3–30. Jahns, S., 1993. On the Holocene vegetation history of the Argive Plain (Peloponnese, southern Greece). Vegetation History and Archaeobotany 2, 187–203. Jahns, S., 2003. A late Holocene pollen diagram from the Megaris, Greece, giving evidence for cultivation of Ceratonia siliqua L. during the last 2000 years. Vegetation History and Archaeobotany 12, 127–130. Kambouroglou, E., 1989. Eretria–paleogeographic and geomorphological evolution during the holocene. Ph.D. Thesis, University of Athens, Municipality of Eretria editions.(in Greek). Kontopoulos, N., Avramidis, P., 2003. A late holocene record of environmental changes from the Aliki lagoon, Egion, North Peloponnesus, Greece. Quaternary International 111, 75–90. Kraft, J.C., 1972. A reconnaissance of the geology of the sandy coastal areas of eastern Greece and the Peloponnese–with special speculations on MiddleLate Helladic paleogeography (3000–4000 years before present). University of Delaware, Technical Report 9, Newark. Kraft, J.C., Aschenbrenner, S.E., Rapp, G.J., 1977. Paleogeographic reconstruction of coastal Aegean archaeological sites. Science 195, 941–947. Kraft, J.C., Rapp, G.J., Aschenbrenner, S.E., 1975. Late Holocene paleogeography of the coastal plain of the Gulf of Messenia, Greece, and its relationships to archaeological settings and coastal change. Geological Society of America Bulletin 86, 1191–1208. Lambeck, K., 1995. Late pleistocene and Holocene sea level change in Greece and southwestern Turkey: a separation of eustatic, isostatic and tectonic contributions. Geophysical Journal International 115, 960–990. Lambeck, K., 1996. Sea level change and shore evolution in Aegean Greece since Upper palaeolithic time. Antiquity 70, 588–611. Lozios, S., 1993. Tectonic Analysis of Northeastern Attica Metamorphic Formations. Ph.D Thesis, University of Athens, Athens (in Greek). (unpublished). Maroukian, H., Zamani, A., Pavlopoulos, K., 1993. Coastal retreat in the plain of Marathon (East Attica), Greece: cause and effects. Geologica Balcanica 23, 67–71. Moore, P.D., Webb, J.A., Collinson, M.E., 1991. Pollen analysis. Blackwell Science, Oxford. Mudie, P.J., Aksu, A.E., Yasar, D., 2001. Late Quaternary dinoflagellate cysts from the Black, Marmara and Aegean seas: variations in assemblages, morphology and paleosalinity. Marine Micropaleontology 43, 155–178. Pantelidou-Gofas, M., 1991. [The Neolithic Nea Makri: the building materials]. The Archaeological Society at Athens Library Series 119, Athens. (in Greek). Pantelidou-Gofas, M., 1995. [The Neolithic Nea Makri: the pottery]. The Archaeological Society at Athens Library Series 153, Athens. (in Greek).

51

Pantelidou-Gofas, M., 1997. The Neolithic Attica. The Archaeological Society at Athens Library Series 167, Athens. Pantelidou-Gofas, M., 2005. [Tsepi Marathonos: the protohelladic cemetery]. The Archaeological Society at Athens Library Series 235, Athens. (in Greek). Pavlopoulos, K., Karkanas, P., Triantaphyllou, M., Karymbalis, E., 2003. Climate and sea level changes recorded during late Holocene in the coastal plain of Marathon, Greece. In: Fouache, E. (Ed.), The Mediterranean World environment and history. Elsevier, Paris, pp. 453–465. Pavlopoulos, K., Karkanas, P., Triantaphyllou, M., Karymbalis, E., Tsourou, Th., Palyvos, N., 2006. Palaeoenvironmental evolution of the coastal plain of Marathon, Greece, during the late Holocene: depositional environment, climate and sea-level changes. Journal of Coastal Research 22, 424–438. Petrakos, B., 1995. Marathon: an Archaeological Guide. The Archaeological Society at Athens Library Series 167, Athens. Petrucci, F., Medioli, F.S., Cavazzini, R., Scott, D.B., 1983. Evaluation of the usefulness of foraminifera as sea level indicators in the Venice lagoon (N. Italy). Acta Naturalia de l’Ateneo Parmense 19, 63–77. Reille, M., 1992–1998. Pollen et spores d’Europe et d’Afrique du Nord (1992). Suppléments 1 (1995), 2 (1998). Laboratoire de Botanique Historique et Palynologie, Marseille. Renault-Miskovsky, J., 1981. Analyse pollinique des sediments de la grotte de Kitsos (Lavrion-Greece). In: Lambert, N. (Ed.), La grotte préhistorique de Kitsos (Attique). Édition ADPF, École Française d’Athènes, Paris, pp. 633–655. Scott, D.B., Piper, D.J.W., Panagos, A.G., 1979. Recent salt marsh and intertidal mudflat foraminifera from the western coast of Greece. Rivista Italiana di Paleontologia e Stratigrafia 85, 243–266. Triantaphyllou, M.V., Pavlopoulos, K., Tsourou, T., Dermitzakis, M.D., 2003. Brackish marsh benthic microfauna and palaeoenvironmental changes during the last 6000 years on the coastal plain of Marathon (SE Greece). Rivista Italiana di Paleontologia e Stratigrafia 109, 539–547. Turner, J., Greig, J.R.A., 1975. Some holocene pollen diagrams from Greece. Review of Palaeobotany and Palynology 20, 171–204. van Andel, T.H., Lianos, N., 1984. High resolution seismic reflection profiles for the reconstruction of postglacial transgressive shorelines: an example from Greece. Quaternary Research 22, 31–45. van Geel, B., Bohncke, S.J.P., Dee, H., 1980-1981. A palaeoecological study of an upper Late Glacial and Holocene sequence from ‘‘De Borchert’’, The Netherlands. Review of Palaeobotany and Palynology 31, 367–448. van Geel, B., Buurman, J., Brinkkemper, O., Schelvis, J., Aptroot, A., van Reenen, G., Hakbijl, T., 2003. Environmental reconstruction of a Roman Period settlement site in Uitgeest (The Netherlands), with a special reference to coprophilous fungi. Journal of Archeological Sciences 30, 833–873. van Geel, B., Coope, G.R., van der Hammen, T., 1989. Palaeoecology and stratigraphy of the Late Glacial type section at Usselo (The Netherlands). Review of Palaeobotany and Palynology 60, 25–129. van Geel, B., Hallewas, D.P., Pals, J.P., 1983. A Late Holocene deposit under the Westfriese Zeedijk near Enkhuizen (Prov. of N-Holland, The Netherlands): palaeoecological and Archaeological aspects. Review of Palaeobotany and Palynology 38, 269–335. Wall, D., Dale, B., Harada, K., 1973. Description of new fossil dinoflagellates from the late Quaternary of the Black Sea. Micropaleontology 19, 18–31.