- Email: [email protected]
A re-evaluation of the basal age in the DSDP hole at Site 534, Central Atlantic
GeoResJ 14 (2017) 59–66
Contents lists available at ScienceDirect
GeoResJ journal homepage: www.elsevier.com/locate/georesj
A re-evaluation of the basal age in the DSDP hole at Site 534, Central Atlantic Leonidas Brikiatis I. Fix 5, Palaeo Faliro, 175 64 Greece
a r t i c l e
i n f o
Article history: Received 28 November 2016 Revised 30 April 2017 Accepted 28 August 2017 Available online 1 September 2017 Keywords: Site 534 Site 801 Middle Oxfordian carbon isotope stratigraphy Hispanic Corridor Blake Spur anomaly
a b s t r a c t For 30 years, the initial sedimentation following the opening of the western Central Atlantic has been considered to be of Middle Callovian age (approximately 164.5 Ma) based on the biochronostratigraphical estimation for the basal sedimentary unit of the borehole from Site 534A of the Deep Sea Drilling Program (DSDP). That age has been used in kinematic models of the opening of the Central Atlantic. A reconsideration of the available biochronostratigraphical data and correlation of the δ ¹³Ccarb record from Site 534A with those from the Tethyan and North Atlantic records suggest that the initial sedimentation at Site 534A is, in fact, of Middle Oxfordian age (approximately 160.6 Ma). The high biostratigraphic similarity among the basal sedimentary units of the boreholes at DSDP Site 534A and Ocean Drilling Program Site 801C in the Western Pacific suggest the same age for both sites. The Middle Oxfordian δ ¹³Ccarb records from the different sites covary, marking the same palaeoenvironmental changes, although such an agreement was not previously acknowledged. A combination with additional data proposes that Middle Oxfordian age corresponds to the precise date of the opening of the Hispanic Corridor between the Atlantic and Pacific oceans. © 2017 Elsevier Ltd. All rights reserved.
1. Introduction The DSDP carried out from 1968 to 1983 offers much to our knowledge of the environmental changes and conditions during the geological ages. Along with other programs, the DSDP included drilling at different sites in the western Central Atlantic, such as Site 534 in the Blake-Bahama Basin [51]. The results from Site 534 access some of the oldest oceanic sediments known from the Atlantic Ocean. The sediments are overlain, breakup-related, seafloor basalts, which were spread at the opening of the Central Atlantic during the breakup of Pangaea [52]. Given the absence of direct radiometric dating, the age of the basalts is regarded as Middle Callovian on the basis of biochronostratigraphical evidence extracted from the basal layers of the borehole [17]. Various geotectonical studies have calibrated models based on the age of the basalts at Site 534A, proposing temporal scenarios for the opening of the Central Atlantic by dating the Blake Spur magnetic anomaly through extrapolation (e.g. [24,26,49]). The radiolarian configuration in the basal sedimentary unit of Site 534A is identical [4,5] to that in the basal sedimentary unit (overlying the upper alkali basalts) of Ocean Drilling Program Site 801C in the Western Pacific (Fig. 1), the location of the oldest ocean crust sampled to date [30]. The core sediments from Site 534A have also
E-mail addresses: [email protected], [email protected] http://dx.doi.org/10.1016/j.grj.2017.08.005 2214-2428/© 2017 Elsevier Ltd. All rights reserved.
been used to extract one of the most cited δ ¹³Ccarb records of the Late Jurassic [23]. Site 534A is located in the eastern gate of the Hispanic Corridor [53], the primitive seaway that is believed to have connected the Pacific and Atlantic oceans and to have separated North and South America since the Jurassic. Therefore, the Middle Callovian is considered the oldest possible sedimentologically confirmed age for the opening of the Hispanic Corridor. It is important to confirm the basal age of the unnamed sequence that overlays the basalts at Site 534A, given the great importance of that site to the geotectonic community. 2. Materials and methods The reconsideration of the basal age at Site 534A included the appraisal of two lines of evidence: 1) the originally inferred biochronostratigraphical data and 2) the correlation of the geochemical graph of the site with other, better-dated graphs from the current literature. Regarding the first line of evidence, in the original publication of the results from Site 534A, the available biochronostratigraphical markers (mainly dinoflagellate cysts) were interpreted to indicate a Middle Callovian age for the basal (still unnamed) sedimentary unit [17]. In a more recent analysis, the radiolarian synthesis from Site 534A was correlated with that extracted from the sedimentation unit on the upper alkali basalts of Site 801C in the
60
L. Brikiatis / GeoResJ 14 (2017) 59–66
Fig. 1. Biochronostratigraphy and locations of the boreholes at sites 534A (1) and 801C (2), as well as the locations of the Trescléoux locality in southeastern France (3) and the Oze locality on the Isle of Sky, Scotland (4), on a palaeogeographic map of the Late Oxfordian. Map modified from Scotese [50]. Biochronostratigraphic chart modified from [4].
Western Pacific Ocean [5]. The concluded radiolarian synthesis was attributed to the UAZ6 (Unitary Association Zone) of the radiolarian biochronostratigraphic chart in 1995 [6], which corresponded to a mid-Bathonian age. In the original publication of the results from Site 801C, a latest Bathonian–earliest Callovian age was attributed to the basal sedimentary strata at Site 801C [32]. More recently, contemporaneous basal sedimentation of the stratigraphical
successions at the two sites was claimed, with a slightly earlier age (UAZ5–6, Late Bajocian to Middle Bathonian) for Site 801C [4]. According to the latter analysis, the basal sedimentation at Site 534A is of a mid-Bathonian age (Fig. 1). In the current study, updated radiolarian biochronostratigraphical data from the current literature were searched in reconsideration of the older biochronostratigraphical estimations.
L. Brikiatis / GeoResJ 14 (2017) 59–66
Regarding the second line of evidence, the δ ¹³Ccarb record from the DSDP borehole at Site 534A [23] was visually correlated and compared with δ ¹³Ccarb records from France [28] and the Isle of Sky, Scotland [36]. The French record includes a highly detailed C-isotope record of the Early to Middle Oxfordian reconstructed from bulk rocks of the Tethyan margin [29]. The measurements (both δ ¹8 O and δ ¹³C) were taken from a composite sequence resulting from sections of the Subalpine Basin in southeastern France (Trescléoux and Oze localities). The Scottish record is also very detailed, providing even more local detail than the record from France, but lacking certain time intervals. For the current investigation, the graphs were reconstructed at maximum resolution from the supplementary material of the original publications ([23,28,36]; see Supplementary Appendix 1). The graphs were reconstructed using the diagramming and vector graphics program Microsoft Visio 2013 (Version 1.0, Standard) and the VSD file format (https://msdn.microsoft.com/en-us/library/ office/fp161226(v=office.15). The correlation and identification were performed using an exclusively manual procedure in which independent parts of the graphs were searched for a common pattern by trial overlays of the reconstructed graphs. In that procedure, the graph from southeastern France was used as the reference base, because it is the most detailed. When a possible similarity was noted, the related graph parts were considered in more detail, and their differences were evaluated as possible consequences of differences in sedimentation rate, sampling, or signal output. To allow for different sedimentation rates among the different records and also within the same record through time, the graphs were cut when discrepancies arose (especially when distal sampling had taken place), releasing the independent segments to find a better matching in the correlation procedure [Figs. 2(A) and 3]. Given the high signal output of the belemnite rostra, the range of values of the belemnite graph was reduced by uniaxial deformation [shrinkage of the belemnite graph in the y-axis (δ ¹³Ccarb values)] in Figs. 2(A) and 4 to focus exclusively on the rhythm of the environmental change and to better visualise the correlation. Special effort was given to investigating the nature of the extra excursions of the Scottish record, which might be due to the noise and the local ecological changes present in the belemnite-extracted signals [36] and/or to unsampled intervals in the record from southeastern France during very variable time periods. The Scottish graph was smoothed and re-compared with the French record using Matlab (version 2011b) in two steps: 1) values were averaged wherever more than one value was given for the same depth; 2) additional smoothing was performed with Matlab’s "smooth" function with the "loess" parameter and 35% span (0.35; see Supplementary Appendix 2). 3. Results Both lines of evidence, biochronostratigraphical and geochemical, suggest that the true age of the basal sedimentary unit is Middle Oxfordian, rather than Middle Callovian. 3.1. Biochronostratigraphical data for sites 534A and 801C In contrast to the prior radiolarian data, a recent radiolarian biochronostratigraphical analysis combined with ammonite biostratigraphy showed that the UAZ 5, 6 and 7, of the 1995 chart, in fact, fall into the Middle Oxfordian interval (plicatilis and transversarium ammonite zones) [7]. Consequently, the basal sedimentation at both Site 534A in the Central Atlantic and Site 801C in the Western Pacific should be considered Middle Oxfordian, rather than Middle Callovian or Bathonian, on the basis of the radiolarian biochronostratigraphy.
61
3.2. Geochemical inter-correlation When the records from Site 534A are correctly aligned with those from southeastern France, a strong similarity is apparent (Fig. 3). Such similarity suggests that the two graphs are contemporaneous. In addition, a careful observation of the fluctuation of the French and Scottish graphs shows that both graphs very probably record the same palaeoenvironmental changes (see Figs. 2 and 4). The differences in covariation are due to the different sampling resolutions, whilst the differences in the value range are due to the different proxies used (belemnites and bulk rocks). Those relationships are more visible in the results of the Matlab processing, in which the two graphs clearly seem to covary (see Supplementary Appendix 2). Furthermore, alignment of the graph parts from Site 534A, southeastern France, and Scotland (Fig. 4) reveals very good matching, suggesting that the records are contemporaneous. Such similarity supports the global character of the records, which has not yet been confirmed. 4. Discussion 4.1. Notes on the geochemical inter-correlation There is a remarkable negative shift in δ ¹³Ccarb during the early transversarium ammonite zone (around the Middle-Late Oxfordian boundary) in the record from SE France, which has also been reported by previous studies [39,40]. Initially, the negative shift was correlated with a methane release episode [39] comparable to other known episodes such as the well-studied episode in the Palaeocene-Eocene boundary. The Palaeocene-Eocene shift accompanied an extreme temperature increase [33]. In contrast, the latest Middle Oxfordian shift accompanied a remarkable temperature decrease, as suggested by the positive δ ¹8 Ocarb excursion in the Tethyan record (Fig. 2). An analogous negative shift can be seen in the δ ¹³Ccarb record extracted from belemnite rostra of a comparable age on the Isle of Sky [36]. The latter shift was reported to be non-congruent with the Tethyan record, however, by the original authors, based on an alignment with an incorrect ammonite chart in which the Boreal tenuiserratum zone almost coincides with the Tethyan transversarium zone. A correct alignment of the two δ ¹³Ccarb records reveals a realistic Boreal-Tethyan correlation (Fig. 2). At least two recent independent ammonite zonations [31, 37] are highly congruent with that shown in Fig. 2. Thus, the available data show that the records from SE France and from Scotland indicate a contemporaneous δ ¹³Ccarb negative excursion near the top of the parandieri subzone and the base of ilovaiskii subzone. In contrast, a similar extreme negative shift was reported as Early Oxfordian in the δ ¹³Ccarb record extracted from basal bulk rocks from Site 534 in the western Central Atlantic [23]. Thus, it was wrongly correlated with the evidently Middle Oxfordian δ ¹³C negative excursions in the Tethyan record [39,40] [J and T diagrams in Fig. 2 of Katz et al. (the T diagram is incorrectly attributed in the figure legend of Katz et al. to “Morettini et al. (2002)”: the R diagram is missing from the figure, and, probably because of that, the references in the figure legend are confused from the letter R onward)]. In fact, the comparable δ ¹³Ccarb negative excursions both fall into the G. transversarium ammonite zone and can safely be regarded as Middle Oxfordian (Fig. 2). 4.2. The exact basal age of site 534A and site 801C As the biochronostratigraphical evidence suggests contemporaneous Middle Oxfordian basal sedimentation in the Central
62
L. Brikiatis / GeoResJ 14 (2017) 59–66
Fig. 2. Correlation between δ ¹³Ccarb records from southeastern France (Tethyan) and the Isle of Sky (N. Atlantic). The ammonite correlation chart (Tethyan and Boreal) is the direct result of a side-by-side fitting of the original ammonite biochronostratigraphic reconstructions supporting the two records. For more explanations, see the text and Methods. Time scale from GTS 2012 [38].
L. Brikiatis / GeoResJ 14 (2017) 59–66
63
Fig. 3. Left graph: correlation of the δ ¹³Ccarb graphs from southeastern France (black) and Site 534A (blue and magenta). The blue line from Site 534A was cut (at the points marked “relaxing” in the right graph) and reconnected to form the magenta line, which allows for differences in the sedimentary rates (see the Materials and Methods). Right graph: reconstruction of the δ ¹³Ccarb record from Site 534A.
Atlantic Site 534A and the Western Pacific Site 801C [4], the detailed δ ¹³Ccarb records suggest an approximately 160.6 Ma age on the basis of the most recent geochronological timescale (Fig. 4). That age is absolutely compatible with the 160.2 ± 0.7 Ma age concluded by 4 0 Ar/³9 Ar radiometric dating for the upper alkali basalts at Site 801C [25] upon which the basal sediment was deposited (Fig. 1). Thus, the evidence from different data sources converges to the same conclusion. 4.3. The basal age of site 534A and the opening of the Hispanic Corridor The concept of an early opening of the Hispanic Corridor is based on marine fauna biogeography suggesting possible early Mesozoic low-latitude marine communication between the Atlantic and Pacific around the area where the Caribbean is located today. The possible existence of such a seaway was discussed from a biogeographical perspective more than 40 years ago [1,8– 10,18,20,21,34,43,53–56]. Different authors have inferred different ages for the starting of the event: Norian [48], Hettangian [27], Sinemurian [57], Pliensbachian [1,3,8,10,43,53], and Toarcian [34]. The most recent and staid of those views are those proposing the Pliensbachian age. More recently, indirect evidence has been reported to support the Early Jurassic existence of the Hispanic Corridor (e.g. [12]); however, the existence of the Hispanic Corridor at so early an age
is not supported by stratigraphical evidence [22]. Therefore, the existence of alternative biogeographical routes, which could explain the observed biogeographical distributions, would be reasonable to suppose. Such an alternative route could be the Viking Corridor (i.e. the primitive Greenland-Norwegian Seaway) named by Westermann [58]. Hallam [19] first proposed an open seaway connecting Arctic and Western Europe seas since the Late Pliensbachian on the basis of the distribution of amaltheid ammonites. The existence of the Viking Corridor in the Late Pliensbachian is supported by both faunal and stratigraphical evidence [11,13,35]; however, its high-latitude location requires ecological compromises by biogeographers [22]. The most powerful faunal argument for the early exposure of the Hispanic Corridor is the existence of the genus Weyla in the Tethys during the Late Pliensbachian [10]. However, as Hallam [19] proposed, the dispersal of Weyla to the Tethys could very well have taken place through the Transgondwanan Seaway rather than through the Hispanic Corridor. The Transgondwanan Seaway is a hypothetical seaway proposed by biogeographers to have been exposed between southeastern Africa and Madagascar (Mozambique Channel), which is a more favourable latitude for marine faunal dispersals [2,14,19,21]. As in the case of the Hispanic Corridor, however, there is currently no stratigraphical evidence to document its exposure in the Early Jurassic [15,16], although such a scenario would be equally possible as the one for the Hispanic Corridor.
64
L. Brikiatis / GeoResJ 14 (2017) 59–66
Fig. 4. Correlation of the three δ ¹³Ccarb records in an interval for which all display a fairly good resolution. The differences between the French and Scottish graphs are possibly due to the different numbers of sampling points covering a highly variable time interval. For explanations of the notices, see the text. The boundary among the Boreal ammonites is not well defined, as was noted in the original study. Note: Only the Tethyan and the Central Atlantic graphs are scaled.
In any case, faunal dispersals through the Hispanic Corridor were sporadic and irregular, suggesting that the exposure of the seaway was episodic and interruptible and/or acted as a filter dispersal route [1,34]. The re-dating of the sequence base at Site 534A provides evidence for the existence of a marine environment on the east side of the seaway since the Middle Oxfordian. Given that a marine environment had already formed on the west side of the BahamasFlorida area during the Oxfordian in the Gulf of Mexico and, in particular, since the Middle-Late Oxfordian in West Cuba [22], the Middle Oxfordian is the earliest stratigraphically documented age for a wide opening of the Hispanic Corridor, although earlier episodic and limited exposures might have also taken place. Given that the opening occurred through a prolonged tectonic procedure, the trigger to the mature palaeogeographical conditions was probably given by a sea level high-stand episode. Such a major transgressive episode in the Russian platform was reported to start from the densiplicatum zone and culminate in the tenuiserratum zone [46]. There is also some indirect evidence supporting a remarkable opening of the Hispanic Corridor in the Middle Oxfordian. Thus, a distinct change in the Tethyan oceanography, corresponding to the transition from hardgrounds to nodular limestone deposition, was constrained in the upper part of the plicatilis ammonite zone and was also attributed to the opening of the Hispanic Corridor [42]. Furthermore, the High Temperature Event (HTE) noted in Fig. 2, which coincides both with a δ ¹³Ccarb negative excursion and with the age of the basal sedimentation at Site 534A, is very likely to be a consequence of the opening of the Hispanic Corridor. In this frame, the δ ¹³Ccarb negative shift that accompanies the HTE (Fig. 2) could be explained by global and remarkable sea-
water warming, given that warmer waters are isotopically lighter than colder waters (e.g. [47]). Such a warming episode has been documented in the Russian Platform from the upper densiplicatum zone to the lower tenuiserratum zone, which is when Tethyan/SubMediterranean ammonites invaded the Middle Russian Sea from the southeast, suggesting a reduction of the temperature gradient between the Sub-Mediterranean and Boreal basins [44,45]. Given that the oceanic circulation currents dominate the Earth’s climatic system (e.g. [41]), the opening of the Hispanic Corridor could have perturbed the equilibrium of the oceanic circulation currents by linking the waters of the Atlantic and Pacific oceans, resulting in the observed warming episode.
5. Conclusions The basal sedimentary units of the boreholes at DSDP Site 534A and Ocean Drilling Program Site 801C in the Western Pacific are of Middle Oxfordian age. The Middle Oxfordian δ ¹³Ccarb records from different sites in the Central Atlantic, southeastern France, and Scotland covary, marking the same palaeoenvironmental changes, although such an agreement was not previously acknowledged. Furthermore, a combination of data proposes that a Middle Oxfordian age corresponds to the precise date of the wide opening of the Hispanic Corridor.
Acknowledgements The author would like to thank Prof. Miriam E. Katz for the supply of the supplementary file of the geochemical record from the DSDP borehole at Site 534A.
L. Brikiatis / GeoResJ 14 (2017) 59–66
Supplementary materials Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.grj.2017.08.005.
[21]
[22]
References [1] Aberhan M. Bivalve palaeobiogeography and the Hispanic Corridor: time of opening and effectiveness of a proto-Atlantic seaway. Palaeogeogr Palaeoclimatol Palaeoecol 2001;165:375–94. http://dx.doi.org/10.1016/S0 031-0182(0 0) 00172-3. [2] Alberti M, Fürsich FT, Pandey DK. The Oxfordian stable isotope record (δ ;18 O, δ ;13 C) of belemnites, brachiopods, and oysters from the Kachchh Basin (western India) and its potential for palaeoecologic, palaeoclimatic, and palaeogeographic reconstructions. Palaeogeogr Palaeoclimatol Palaeoecol 2012;344345:49–68. doi: http://dx.doi.org/10.1016/j.palaeo.2012.05.018 . [3] Arias C. Northern and Southern Hemispheres ostracod palaeobiogeography during the Early Jurassic: possible migration routes. Palaeogeogr Palaeoclimatol Palaeoecol 2006;233:63–95. doi: http://dx.doi.org/10.1016/j.palaeo.2005. 09.006 . [4] Bartolini A, Larson RL. Pacific microplate and the Pangea supercontinent in the Early to Middle Jurassic. Geology 2001;29:735–8. doi: http://dx.doi.org/ 10.1130/0091-7613(2001) . [5] Baumgartner PO, Matsuoka A. New radiolarian data from DSDP Site 534, Blake Bahama Basin, central Northern Atlantic. In: Baumgartner PO, et al., editors. Middle jurassic to lower cretaceous radiolaria of Tethys: occurrences, systematics, biochronology, 23. Lausanne, Switzerland: Memoires de Geologie; 1995. p. 709–15. [6] Baumgartner PO, et al. Middle Jurassic to Early Cretaceous radiolarian biochronology of Tethys based on Unitary Associations. In: Baumgartner PO, et al., editors. Middle jurassic to lower cretaceous radiolaria of Tethys: occurrences, systematics, biochronology, 23. Lausanne: Memoires de Geologie; 1995. p. 1013–43. [7] Beccaro P. Radiolarian correlation of Jurassic siliceous successions of the Rosso Ammonitico Formation in the Southern Alps and Western Sicily (Italy). Eclogae Geologicae Helvetiae 2006;99:S21–33. doi: http://dx.doi.org/10.1007/ s0 0 015-0 06-0607-0 . [8] Damborenea SE, Manceñido MO. On the palaeogeographical distribution of the pectinid genus Weyla (Bivalvia, Lower Jurassic). Palaeogeogr Palaeoclimatol Palaeoecol 1979;27:85–102. doi: http://dx.doi.org/10.1016/0031-0182(79) 90095-6 . [9] Damborenea SE. Hispanic Corridor: its evolution and the biogeography of bivalve mollusks. In: Hall RL, Smith PL, editors. Advances in jurassic research 20 0 0, 6. Geo Research Forum; 20 0 0. p. 369–80. [10] Damborenea SE, Echevarría J, Ros-Franch S. Southern Hemisphere palaeobiogeography of Triassic-Jurassic marine bivalves. Springer Briefs Seaways and Landbridges: Southern Hemisphere Biogeographic Connections Through Time; 2013. doi: http://dx.doi.org/10.1007/978- 94- 007- 5098- 2_1 . [11] Dera G, Neige P, Dommergues J-L, Brayard A. Ammonite paleobiogeography during the Pliensbachian–Toarcian crisis (Early Jurassic) reflecting paleoclimate, eustasy, and extinctions. Glob Planet Chang 2011;78:92–105. doi: http: //dx.doi.org/10.1016/j.gloplacha.2011.05.009 . [12] Dera G, Prunier J, Smith PL, Haggart JW, Popov E, Guzhov A. Nd isotope constraints on ocean circulation, paleoclimate, and continental drainage during the Jurassic breakup of Pangea. Gondwana Res 2015;27:1599–615. doi: http://dx.doi.org/10.1016/j.gr.2014.02.006 . [13] Doré AG. The structural foundation and evolution of Mesozoic seaways between Europe and the Arctic. Palaeogeogr Palaeoclimatol Palaeoecol 1991;87:441–92. doi: http://dx.doi.org/10.1016/0031-0182(91)90144-G . [14] Doyle P, Howlett P. Antarctic belemnite biogeography and the break-up of Gondwana. Geol Soc London Special Publ 1989;47:167–82. doi: http://dx.doi. org/10.1144/GSL.SP.1989.047.01.13 . [15] Geiger M. Reappraisal of the timing of the breakup of Gondwana based on sedimentological and seismic evidence from the Morondava Basin, Madagascar. J Afr Earth Sci. 2004;38:363–81. doi: http://dx.doi.org/10.1016/S0899-5362(04) 0 0 030-2. [16] Geiger M, Schweigert G. Toarcian–Kimmeridgian depositional cycles of the south-western Morondava Basin along the rifted continental margin of Madagascar. Facies 2006;52:85. doi: http://dx.doi.org/10.1007/s10347- 005- 0039- 8 . [17] Habib D, Drugg WS, et al. Dinoflagellate age of Middle Jurassic-Early Cretaceous sediments in the Blake-Bahama Basin. In: Sheridan RE, editor. Deep sea drilling project. Washington: U.S. Govt. Printing Office; 1983. p. 623–38. Initial Reports, v.76 http://dx.doi.org/10.2973/dsdp.proc.76.126.1983 . [18] Hallam A. Provinciality, diversity and extinction of Mesozoic marine invertebrates in relation to plate movements, in: Tarling DH, Runcorn, SK. (Eds), Implications of continental drift to the Earth sciences, Vol. 1. Academic Press, London, 1973; pp. 287–294. [19] Hallam A. Distributional patterns in contemporary terrestrial and marine animals, in: Hughes, NF, (Ed), Organisms and continents through time. Special Papers in Palaeontology 1973; 12:93–105. Available online at: http://cdn.palass.org/publications/special_papers_in_palaeontology/spp_12/ pdf/spp12_pp93-106.pdf. [20] Hallam A. Biogeographic evidence bearing on the creation of Atlantic seaways in the Jurassic, in: West, RM. (Ed), Paleontology and Plate tectonics: Proceeding of a Symposium presented at the North American Paleontological Convention
[23]
[24]
[25]
[26]
[27]
[28] [29]
[30]
[31]
[32]
[33]
[34]
[35]
[36]
[37]
[38]
[39]
[40]
[41]
[42]
[43]
[44]
65
II. Milwaukee Public Museum: Special Publication in Biology and Geology vol. 2; 1977, pp. 23–34. Hallam. Early and mid-jurassic molluscan biogeography and the establishment of the central Atlantic seaway. Palaeogeogr Palaeoclimatol Palaeoecol 1983;43:181–93. doi: http://dx.doi.org/10.1016/0031-0182(83)90010-X . Iturralde-Vinent M. Meso-Cenozoic Caribbean paleogeography: implications for the Historical Biogeography of the region. Int Geol Rev 2006;48:791–827. doi: http://dx.doi.org/10.2747/0020-6814.48.9.791 . Katz ME, Wright JD, Miller KG, Cramer BS, Fennel K, Falkowski PG. Biological overprint of the geological carbon cycle. Marine Geol 2005;217:323–38. doi: http://dx.doi.org/10.1016/j.margeo.20 04.08.0 05 . Klitgord KD, Schouten H. Plate kinematics of the central Atlantic. In: Vogt PR, Tucholke BE, editors. The geology of north America: the western north atlantic region, Vol. M. Boulder, CO: Geological Society of America; 1986. p. 351–78. Koppers AAP, Staudigel H, Duncan RA. High-resolution 40Ar/39Ar dating of the oldest oceanic basement basalts in the western Pacific basin. Geochem Geophys Geosyst 2003;4:11. doi: http://dx.doi.org/10.1029/20 03GC0 0 0574 . Labails C, Olivet J-L, Aslanian D, Roest WR. An alternative early opening scenario for the Central Atlantic Ocean. Earth Planet Sci Lett 2010;297:355–68. doi: http://dx.doi.org/10.1016/j.epsl.2010.06.024 . Longridge LM, Smith PL, Pálfy J, Tipper HW. Three New Species of the Hettangian (Early Jurassic) Ammonite Sunrisites from British Columbia, Canada. J Paleontol 2008;82:128–39. doi: http://dx.doi.org/10.1666/05-158.1 . Louis-Schmid B. Feedback mechanisms between carbon cycling, climate and oceanography. Zürich: Federal Institute of Technology ETH; 2006. Louis-Schmid B, Rais P, Bernasconi SM, Pellenard P, Collin P-Y, Weissert H. Detailed record of the mid-Oxfordian (Late Jurassic) positive carbon-isotope excursion in two hemipelagic sections (France and Switzerland): A plate tectonic trigger? Palaeogeogr Palaeoclimatol Palaeoecol 2007;248:459–72. doi: http://dx.doi.org/10.1016/j.palaeo.2007.01.001 . Ludden JN, Plank T, Larson R, Escutia C. Leg 185 synthesis: sampling the oldest crust in the ocean basins to understand Earth’s geodynamic and geochemical fluxes. In: Ludden JN, Plank T, Escutia C, editors. Proc. ODP, Sci. Results; 2006. p. 1–35. 185[Online]. Available from http://www-odp.tamu.edu/publications/ 185_sr/VOLUME/SYNTH/SYNTH.PDF . Martin-Garin B, Lathuilière B, Geister J. The shifting biogeography of reef corals during the Oxfordian (Late Jurassic). A climatic control? Palaeogeogr Palaeoclimatol Palaeoecol 2012;365–366:136–53. doi: http://dx.doi.org/10.1016/j. palaeo.2012.09.022 . Matsuoka A, et al. Jurassic and Early Cretaceous radiolarians from Leg 129, Sites 800 and 801, Western Pacific Ocean. In: Larson RL, Lancelot Y, et al., editors. 1992 Proceedings of the Ocean Drilling Program, Scientific Results; 1992. p. 203–20. Vol. 129. doi: http://dx.doi.org/10.2973/odp.proc.sr.129.121.1992 McInerney FA, Wing SL. The Paleocene-Eocene Thermal Maximum: a perturbation of carbon cycle, climate, and biosphere with implications for the future. Ann Rev Earth Planet Sci 2011;39:489–516. doi: http://dx.doi.org/10. 1146/annurev- earth- 040610- 133431 . Moyne S, Neige P, Marchand D, Thierry J. World distribution of middle Jurassic ammonites (Upper Aalenian to Middle Bathonian): relationships between biodiversity and palaeogeography. Bulletin de la Société Géologique de France 2004;175:513–23. doi: http://dx.doi.org/10.2113/175.5.513 . Nikitenko B, Shurygin B, Mickey MB. High resolution stratigraphy of the Lower Jurassic and Aalenian of Arctic regions as the basis for detailed palaeobiogeographic reconstructions. Norw J Geol 2008;88:267–78. Available at: http: //www.geologi.no/images/NJG_articles/NJG_Nikitenko_et_al_4_2008_print.pdf . Nunn EV, Price GD, Hart MB, Page KN, Leng MJ. Isotopic signals from Callovian–Kimmeridgian (Middle–Upper Jurassic) belemnites and bulk organic carbon, Staffin Bay, Isle of Skye, Scotland. J Geol Soc 2009;166:633–41. doi: http://dx.doi.org/10.1144/0 016-764920 08-067 . Ogg JG, Ogg G. Updated biochronostratigraphical chart of the Late Jurassic . (accessed on 20 November 2016) Available online at: doi: https://engineering. purdue.edu/Stratigraphy/charts/Timeslices/5_JurCret.pdf. Ogg JG, Hinnov LA. Chapter 26: Jurassic. In: Gradstein FM, Ogg JG, Schmitz MD, Ogg GM, editors. The geologic time scale 2012. Amsterdam: Elsevier; 2012. p. 731–91. doi: http://dx.doi.org/10.1016/B978- 0- 444- 59425- 9.0 0 026-3. Padden M, Weissert H, de Rafelis M. Evidence for Late Jurassic release of methane from gas hydrate. Geology 2001;29:223–6. doi: http://dx.doi.org/10. 1130/0091-7613(2001)0290223:EFLJRO203;2.0.CO;2 . Padden M, Weissert H, Funk H, Schneider S, Gansner C. Late Jurassic lithological evolution and carbon-isotope stratigraphy of the western Tethys. Eclogae Geologicae Helvetiae 2002;95:333–46. Available at: http://www.e-periodica. ch/digbib/view?pid=egh-0 01:20 02:95::359#359 . Parrish JT. Jurassic climate and oceanography of the Pacific region. In: Westermann GEG, editor. The jurassic of the circum-Pacific. London: Cambridge University Press; 1992. p. 365–80. doi: https://doi.org/10.1017/CBO9780511529375. 029. Rais P, Louis-Schmid B, Bernasconi SM, Weissert H. Palaeoceanographic and palaeoclimatic reorganization around the Middle–Late Jurassic transition. Palaeogeogr Palaeoclimatol Palaeoecol 2007;251:527–46. doi: http://dx.doi. org/10.1016/j.palaeo.20 07.05.0 08 . Riccardi AC. Jurassic and cretaceous marine connections between the Southeast Pacific and Tethys. Palaeogeogr, Palaeoclimatol, Palaeoecol 1991;87:155– 89. doi: http://dx.doi.org/10.1016/0031-0182(91)90134-D . Rogov MA. Ways of migrations and correlative potential of the Middle Oxfordian ammonites: new data from the Russian plate. In: Proceedings of
66
[45]
[46]
[47]
[48]
[49]
[50]
[51]
L. Brikiatis / GeoResJ 14 (2017) 59–66 the International Conference Paleobiogeography and Paleoecology 20 01; 20 02. p. 181–2. Rogov M, Zakharov V, Kiselev D. Molluscan immigrations via biogeographical ecotone of the Middle Russian Sea during the Jurassic. Volumina Jurassica 2008;6:143–52. Sahagian D, Pinous O, Olferiev A, Zakharov V. Eustatic curve for the Middle Jurassic–Cretaceous based on Russian Platform and Siberian Stratigraphy: zonal resolution. Am Assoc Pet Geol Bull 1996;80:1433–58. Saltzman MR, Thomas E. Chapter 11: Carbon Isotope Stratigraphy. In: Gradstein FM, Ogg JG, Schmitz MD, Ogg GM, editors. The geologic time scale 2012. Amsterdam: Elsevier; 2012. p. 207–32. doi: http://dx.doi.org/10.1016/ B978- 0- 444- 59425- 9.0 0 011-1. Sandy MR, Stanley GD Jr. Late Triassic brachiopods from the Luning Formation, Nevada, and their palaeobiogeographical significance. Palaeontology 1993;36:439–80. Available at: http://cdn.palass.org/publications/ palaeontology/volume_36/pdf/vol36_part2_pp439-480.pdf . Schettino A, Turco E. Breakup of Pangaea and plate kinematics of the central Atlantic and Atlas regions. Geophys J Int 2009;178:1078–97. doi: http://dx.doi. org/10.1111/j.1365-246X.2009.04186.x . Scotese CR. Atlas of Jurassic Paleogeographic Maps, PALEOMAP Atlas for ArcGIS, volume 3, The Jurassic and Triassic, Maps 32 - 42, Mollweide Projection, Evanston, IL: PALEOMAP Project; 2014. Technical Report. doi: http://dx.doi.org/ 10.13140/2.1.4850.4321 . Sheridan RE, Gradstein FM, et al. In: Sheridan RE, et al., editors. Site 534: blake-bahama basin. Washington: Deep Sea Drilling Project; 1983. p. 141–340. Initial Reports 76 doi: http://dx.doi.org/10.2973/dsdp.proc.76.104.1983.
[52] Sheridan RE, Gradstein FM, Barnard LA, Bliefnick DM, Habib D, et al. Early history of the Atlantic Ocean and gas hydrates on the Blake Outer Ridge: results of the Deep Sea Drilling Project Leg 76 Papers in the Earth and Atmospheric Sciences. Paper 257 http://digitalcommons.unl.edu/geosciencefacpub/257. [53] Smith PL. The Pliensbachian ammonite Dayiceras dayiceroides and Early Jurassic paleogeography. Can J Earth Sci 1983;20:86–91. doi: http://dx.doi.org/10. 1139/e83-008 . [54] Smith PL, Tipper HW. Plate tectonics and paleobiogeography: Early Jurassic (Pliensbachian) endemism and diversity. Palaios 1986;1:399–412. http://www. jstor.org/stable/3514477. [55] Smith. Paleobiogeography and plate tectonics. Geosci Can 1989;15:261–79. Available online at: https://journals.lib.unb.ca/index.php/GC/article/view/3575/ 4089 . [56] Stanley GD Jr. Late Paleozoic and Early Mesozoic reef-building organisms and paleogeography: the Tethyan-North American connection. Courier Forschungsinstitut Senkenberg 1994;172:69–75. [57] Venturi F, Bilotta M, Ricci C. Comparison between western Tethys and eastern Pacific ammonites: further evidence for a possible late Sinemurian–early Pliensbachian trans-Pangaean marine connection. Geol Mag 2006;143:699–711. [58] Westermann GEG. Global bio-events in mid-Jurassic ammonites controlled by seaways. In: House MR, editor. The Ammonoidea: Environment, ecology and evolutionary change. Oxford: Clarendon Press; 1993. p. 187–226. Systematics Association Special Volume Series 47.
Contents lists available at ScienceDirect
GeoResJ journal homepage: www.elsevier.com/locate/georesj
A re-evaluation of the basal age in the DSDP hole at Site 534, Central Atlantic Leonidas Brikiatis I. Fix 5, Palaeo Faliro, 175 64 Greece
a r t i c l e
i n f o
Article history: Received 28 November 2016 Revised 30 April 2017 Accepted 28 August 2017 Available online 1 September 2017 Keywords: Site 534 Site 801 Middle Oxfordian carbon isotope stratigraphy Hispanic Corridor Blake Spur anomaly
a b s t r a c t For 30 years, the initial sedimentation following the opening of the western Central Atlantic has been considered to be of Middle Callovian age (approximately 164.5 Ma) based on the biochronostratigraphical estimation for the basal sedimentary unit of the borehole from Site 534A of the Deep Sea Drilling Program (DSDP). That age has been used in kinematic models of the opening of the Central Atlantic. A reconsideration of the available biochronostratigraphical data and correlation of the δ ¹³Ccarb record from Site 534A with those from the Tethyan and North Atlantic records suggest that the initial sedimentation at Site 534A is, in fact, of Middle Oxfordian age (approximately 160.6 Ma). The high biostratigraphic similarity among the basal sedimentary units of the boreholes at DSDP Site 534A and Ocean Drilling Program Site 801C in the Western Pacific suggest the same age for both sites. The Middle Oxfordian δ ¹³Ccarb records from the different sites covary, marking the same palaeoenvironmental changes, although such an agreement was not previously acknowledged. A combination with additional data proposes that Middle Oxfordian age corresponds to the precise date of the opening of the Hispanic Corridor between the Atlantic and Pacific oceans. © 2017 Elsevier Ltd. All rights reserved.
1. Introduction The DSDP carried out from 1968 to 1983 offers much to our knowledge of the environmental changes and conditions during the geological ages. Along with other programs, the DSDP included drilling at different sites in the western Central Atlantic, such as Site 534 in the Blake-Bahama Basin [51]. The results from Site 534 access some of the oldest oceanic sediments known from the Atlantic Ocean. The sediments are overlain, breakup-related, seafloor basalts, which were spread at the opening of the Central Atlantic during the breakup of Pangaea [52]. Given the absence of direct radiometric dating, the age of the basalts is regarded as Middle Callovian on the basis of biochronostratigraphical evidence extracted from the basal layers of the borehole [17]. Various geotectonical studies have calibrated models based on the age of the basalts at Site 534A, proposing temporal scenarios for the opening of the Central Atlantic by dating the Blake Spur magnetic anomaly through extrapolation (e.g. [24,26,49]). The radiolarian configuration in the basal sedimentary unit of Site 534A is identical [4,5] to that in the basal sedimentary unit (overlying the upper alkali basalts) of Ocean Drilling Program Site 801C in the Western Pacific (Fig. 1), the location of the oldest ocean crust sampled to date [30]. The core sediments from Site 534A have also
E-mail addresses: [email protected], [email protected] http://dx.doi.org/10.1016/j.grj.2017.08.005 2214-2428/© 2017 Elsevier Ltd. All rights reserved.
been used to extract one of the most cited δ ¹³Ccarb records of the Late Jurassic [23]. Site 534A is located in the eastern gate of the Hispanic Corridor [53], the primitive seaway that is believed to have connected the Pacific and Atlantic oceans and to have separated North and South America since the Jurassic. Therefore, the Middle Callovian is considered the oldest possible sedimentologically confirmed age for the opening of the Hispanic Corridor. It is important to confirm the basal age of the unnamed sequence that overlays the basalts at Site 534A, given the great importance of that site to the geotectonic community. 2. Materials and methods The reconsideration of the basal age at Site 534A included the appraisal of two lines of evidence: 1) the originally inferred biochronostratigraphical data and 2) the correlation of the geochemical graph of the site with other, better-dated graphs from the current literature. Regarding the first line of evidence, in the original publication of the results from Site 534A, the available biochronostratigraphical markers (mainly dinoflagellate cysts) were interpreted to indicate a Middle Callovian age for the basal (still unnamed) sedimentary unit [17]. In a more recent analysis, the radiolarian synthesis from Site 534A was correlated with that extracted from the sedimentation unit on the upper alkali basalts of Site 801C in the
60
L. Brikiatis / GeoResJ 14 (2017) 59–66
Fig. 1. Biochronostratigraphy and locations of the boreholes at sites 534A (1) and 801C (2), as well as the locations of the Trescléoux locality in southeastern France (3) and the Oze locality on the Isle of Sky, Scotland (4), on a palaeogeographic map of the Late Oxfordian. Map modified from Scotese [50]. Biochronostratigraphic chart modified from [4].
Western Pacific Ocean [5]. The concluded radiolarian synthesis was attributed to the UAZ6 (Unitary Association Zone) of the radiolarian biochronostratigraphic chart in 1995 [6], which corresponded to a mid-Bathonian age. In the original publication of the results from Site 801C, a latest Bathonian–earliest Callovian age was attributed to the basal sedimentary strata at Site 801C [32]. More recently, contemporaneous basal sedimentation of the stratigraphical
successions at the two sites was claimed, with a slightly earlier age (UAZ5–6, Late Bajocian to Middle Bathonian) for Site 801C [4]. According to the latter analysis, the basal sedimentation at Site 534A is of a mid-Bathonian age (Fig. 1). In the current study, updated radiolarian biochronostratigraphical data from the current literature were searched in reconsideration of the older biochronostratigraphical estimations.
L. Brikiatis / GeoResJ 14 (2017) 59–66
Regarding the second line of evidence, the δ ¹³Ccarb record from the DSDP borehole at Site 534A [23] was visually correlated and compared with δ ¹³Ccarb records from France [28] and the Isle of Sky, Scotland [36]. The French record includes a highly detailed C-isotope record of the Early to Middle Oxfordian reconstructed from bulk rocks of the Tethyan margin [29]. The measurements (both δ ¹8 O and δ ¹³C) were taken from a composite sequence resulting from sections of the Subalpine Basin in southeastern France (Trescléoux and Oze localities). The Scottish record is also very detailed, providing even more local detail than the record from France, but lacking certain time intervals. For the current investigation, the graphs were reconstructed at maximum resolution from the supplementary material of the original publications ([23,28,36]; see Supplementary Appendix 1). The graphs were reconstructed using the diagramming and vector graphics program Microsoft Visio 2013 (Version 1.0, Standard) and the VSD file format (https://msdn.microsoft.com/en-us/library/ office/fp161226(v=office.15). The correlation and identification were performed using an exclusively manual procedure in which independent parts of the graphs were searched for a common pattern by trial overlays of the reconstructed graphs. In that procedure, the graph from southeastern France was used as the reference base, because it is the most detailed. When a possible similarity was noted, the related graph parts were considered in more detail, and their differences were evaluated as possible consequences of differences in sedimentation rate, sampling, or signal output. To allow for different sedimentation rates among the different records and also within the same record through time, the graphs were cut when discrepancies arose (especially when distal sampling had taken place), releasing the independent segments to find a better matching in the correlation procedure [Figs. 2(A) and 3]. Given the high signal output of the belemnite rostra, the range of values of the belemnite graph was reduced by uniaxial deformation [shrinkage of the belemnite graph in the y-axis (δ ¹³Ccarb values)] in Figs. 2(A) and 4 to focus exclusively on the rhythm of the environmental change and to better visualise the correlation. Special effort was given to investigating the nature of the extra excursions of the Scottish record, which might be due to the noise and the local ecological changes present in the belemnite-extracted signals [36] and/or to unsampled intervals in the record from southeastern France during very variable time periods. The Scottish graph was smoothed and re-compared with the French record using Matlab (version 2011b) in two steps: 1) values were averaged wherever more than one value was given for the same depth; 2) additional smoothing was performed with Matlab’s "smooth" function with the "loess" parameter and 35% span (0.35; see Supplementary Appendix 2). 3. Results Both lines of evidence, biochronostratigraphical and geochemical, suggest that the true age of the basal sedimentary unit is Middle Oxfordian, rather than Middle Callovian. 3.1. Biochronostratigraphical data for sites 534A and 801C In contrast to the prior radiolarian data, a recent radiolarian biochronostratigraphical analysis combined with ammonite biostratigraphy showed that the UAZ 5, 6 and 7, of the 1995 chart, in fact, fall into the Middle Oxfordian interval (plicatilis and transversarium ammonite zones) [7]. Consequently, the basal sedimentation at both Site 534A in the Central Atlantic and Site 801C in the Western Pacific should be considered Middle Oxfordian, rather than Middle Callovian or Bathonian, on the basis of the radiolarian biochronostratigraphy.
61
3.2. Geochemical inter-correlation When the records from Site 534A are correctly aligned with those from southeastern France, a strong similarity is apparent (Fig. 3). Such similarity suggests that the two graphs are contemporaneous. In addition, a careful observation of the fluctuation of the French and Scottish graphs shows that both graphs very probably record the same palaeoenvironmental changes (see Figs. 2 and 4). The differences in covariation are due to the different sampling resolutions, whilst the differences in the value range are due to the different proxies used (belemnites and bulk rocks). Those relationships are more visible in the results of the Matlab processing, in which the two graphs clearly seem to covary (see Supplementary Appendix 2). Furthermore, alignment of the graph parts from Site 534A, southeastern France, and Scotland (Fig. 4) reveals very good matching, suggesting that the records are contemporaneous. Such similarity supports the global character of the records, which has not yet been confirmed. 4. Discussion 4.1. Notes on the geochemical inter-correlation There is a remarkable negative shift in δ ¹³Ccarb during the early transversarium ammonite zone (around the Middle-Late Oxfordian boundary) in the record from SE France, which has also been reported by previous studies [39,40]. Initially, the negative shift was correlated with a methane release episode [39] comparable to other known episodes such as the well-studied episode in the Palaeocene-Eocene boundary. The Palaeocene-Eocene shift accompanied an extreme temperature increase [33]. In contrast, the latest Middle Oxfordian shift accompanied a remarkable temperature decrease, as suggested by the positive δ ¹8 Ocarb excursion in the Tethyan record (Fig. 2). An analogous negative shift can be seen in the δ ¹³Ccarb record extracted from belemnite rostra of a comparable age on the Isle of Sky [36]. The latter shift was reported to be non-congruent with the Tethyan record, however, by the original authors, based on an alignment with an incorrect ammonite chart in which the Boreal tenuiserratum zone almost coincides with the Tethyan transversarium zone. A correct alignment of the two δ ¹³Ccarb records reveals a realistic Boreal-Tethyan correlation (Fig. 2). At least two recent independent ammonite zonations [31, 37] are highly congruent with that shown in Fig. 2. Thus, the available data show that the records from SE France and from Scotland indicate a contemporaneous δ ¹³Ccarb negative excursion near the top of the parandieri subzone and the base of ilovaiskii subzone. In contrast, a similar extreme negative shift was reported as Early Oxfordian in the δ ¹³Ccarb record extracted from basal bulk rocks from Site 534 in the western Central Atlantic [23]. Thus, it was wrongly correlated with the evidently Middle Oxfordian δ ¹³C negative excursions in the Tethyan record [39,40] [J and T diagrams in Fig. 2 of Katz et al. (the T diagram is incorrectly attributed in the figure legend of Katz et al. to “Morettini et al. (2002)”: the R diagram is missing from the figure, and, probably because of that, the references in the figure legend are confused from the letter R onward)]. In fact, the comparable δ ¹³Ccarb negative excursions both fall into the G. transversarium ammonite zone and can safely be regarded as Middle Oxfordian (Fig. 2). 4.2. The exact basal age of site 534A and site 801C As the biochronostratigraphical evidence suggests contemporaneous Middle Oxfordian basal sedimentation in the Central
62
L. Brikiatis / GeoResJ 14 (2017) 59–66
Fig. 2. Correlation between δ ¹³Ccarb records from southeastern France (Tethyan) and the Isle of Sky (N. Atlantic). The ammonite correlation chart (Tethyan and Boreal) is the direct result of a side-by-side fitting of the original ammonite biochronostratigraphic reconstructions supporting the two records. For more explanations, see the text and Methods. Time scale from GTS 2012 [38].
L. Brikiatis / GeoResJ 14 (2017) 59–66
63
Fig. 3. Left graph: correlation of the δ ¹³Ccarb graphs from southeastern France (black) and Site 534A (blue and magenta). The blue line from Site 534A was cut (at the points marked “relaxing” in the right graph) and reconnected to form the magenta line, which allows for differences in the sedimentary rates (see the Materials and Methods). Right graph: reconstruction of the δ ¹³Ccarb record from Site 534A.
Atlantic Site 534A and the Western Pacific Site 801C [4], the detailed δ ¹³Ccarb records suggest an approximately 160.6 Ma age on the basis of the most recent geochronological timescale (Fig. 4). That age is absolutely compatible with the 160.2 ± 0.7 Ma age concluded by 4 0 Ar/³9 Ar radiometric dating for the upper alkali basalts at Site 801C [25] upon which the basal sediment was deposited (Fig. 1). Thus, the evidence from different data sources converges to the same conclusion. 4.3. The basal age of site 534A and the opening of the Hispanic Corridor The concept of an early opening of the Hispanic Corridor is based on marine fauna biogeography suggesting possible early Mesozoic low-latitude marine communication between the Atlantic and Pacific around the area where the Caribbean is located today. The possible existence of such a seaway was discussed from a biogeographical perspective more than 40 years ago [1,8– 10,18,20,21,34,43,53–56]. Different authors have inferred different ages for the starting of the event: Norian [48], Hettangian [27], Sinemurian [57], Pliensbachian [1,3,8,10,43,53], and Toarcian [34]. The most recent and staid of those views are those proposing the Pliensbachian age. More recently, indirect evidence has been reported to support the Early Jurassic existence of the Hispanic Corridor (e.g. [12]); however, the existence of the Hispanic Corridor at so early an age
is not supported by stratigraphical evidence [22]. Therefore, the existence of alternative biogeographical routes, which could explain the observed biogeographical distributions, would be reasonable to suppose. Such an alternative route could be the Viking Corridor (i.e. the primitive Greenland-Norwegian Seaway) named by Westermann [58]. Hallam [19] first proposed an open seaway connecting Arctic and Western Europe seas since the Late Pliensbachian on the basis of the distribution of amaltheid ammonites. The existence of the Viking Corridor in the Late Pliensbachian is supported by both faunal and stratigraphical evidence [11,13,35]; however, its high-latitude location requires ecological compromises by biogeographers [22]. The most powerful faunal argument for the early exposure of the Hispanic Corridor is the existence of the genus Weyla in the Tethys during the Late Pliensbachian [10]. However, as Hallam [19] proposed, the dispersal of Weyla to the Tethys could very well have taken place through the Transgondwanan Seaway rather than through the Hispanic Corridor. The Transgondwanan Seaway is a hypothetical seaway proposed by biogeographers to have been exposed between southeastern Africa and Madagascar (Mozambique Channel), which is a more favourable latitude for marine faunal dispersals [2,14,19,21]. As in the case of the Hispanic Corridor, however, there is currently no stratigraphical evidence to document its exposure in the Early Jurassic [15,16], although such a scenario would be equally possible as the one for the Hispanic Corridor.
64
L. Brikiatis / GeoResJ 14 (2017) 59–66
Fig. 4. Correlation of the three δ ¹³Ccarb records in an interval for which all display a fairly good resolution. The differences between the French and Scottish graphs are possibly due to the different numbers of sampling points covering a highly variable time interval. For explanations of the notices, see the text. The boundary among the Boreal ammonites is not well defined, as was noted in the original study. Note: Only the Tethyan and the Central Atlantic graphs are scaled.
In any case, faunal dispersals through the Hispanic Corridor were sporadic and irregular, suggesting that the exposure of the seaway was episodic and interruptible and/or acted as a filter dispersal route [1,34]. The re-dating of the sequence base at Site 534A provides evidence for the existence of a marine environment on the east side of the seaway since the Middle Oxfordian. Given that a marine environment had already formed on the west side of the BahamasFlorida area during the Oxfordian in the Gulf of Mexico and, in particular, since the Middle-Late Oxfordian in West Cuba [22], the Middle Oxfordian is the earliest stratigraphically documented age for a wide opening of the Hispanic Corridor, although earlier episodic and limited exposures might have also taken place. Given that the opening occurred through a prolonged tectonic procedure, the trigger to the mature palaeogeographical conditions was probably given by a sea level high-stand episode. Such a major transgressive episode in the Russian platform was reported to start from the densiplicatum zone and culminate in the tenuiserratum zone [46]. There is also some indirect evidence supporting a remarkable opening of the Hispanic Corridor in the Middle Oxfordian. Thus, a distinct change in the Tethyan oceanography, corresponding to the transition from hardgrounds to nodular limestone deposition, was constrained in the upper part of the plicatilis ammonite zone and was also attributed to the opening of the Hispanic Corridor [42]. Furthermore, the High Temperature Event (HTE) noted in Fig. 2, which coincides both with a δ ¹³Ccarb negative excursion and with the age of the basal sedimentation at Site 534A, is very likely to be a consequence of the opening of the Hispanic Corridor. In this frame, the δ ¹³Ccarb negative shift that accompanies the HTE (Fig. 2) could be explained by global and remarkable sea-
water warming, given that warmer waters are isotopically lighter than colder waters (e.g. [47]). Such a warming episode has been documented in the Russian Platform from the upper densiplicatum zone to the lower tenuiserratum zone, which is when Tethyan/SubMediterranean ammonites invaded the Middle Russian Sea from the southeast, suggesting a reduction of the temperature gradient between the Sub-Mediterranean and Boreal basins [44,45]. Given that the oceanic circulation currents dominate the Earth’s climatic system (e.g. [41]), the opening of the Hispanic Corridor could have perturbed the equilibrium of the oceanic circulation currents by linking the waters of the Atlantic and Pacific oceans, resulting in the observed warming episode.
5. Conclusions The basal sedimentary units of the boreholes at DSDP Site 534A and Ocean Drilling Program Site 801C in the Western Pacific are of Middle Oxfordian age. The Middle Oxfordian δ ¹³Ccarb records from different sites in the Central Atlantic, southeastern France, and Scotland covary, marking the same palaeoenvironmental changes, although such an agreement was not previously acknowledged. Furthermore, a combination of data proposes that a Middle Oxfordian age corresponds to the precise date of the wide opening of the Hispanic Corridor.
Acknowledgements The author would like to thank Prof. Miriam E. Katz for the supply of the supplementary file of the geochemical record from the DSDP borehole at Site 534A.
L. Brikiatis / GeoResJ 14 (2017) 59–66
Supplementary materials Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.grj.2017.08.005.
[21]
[22]
References [1] Aberhan M. Bivalve palaeobiogeography and the Hispanic Corridor: time of opening and effectiveness of a proto-Atlantic seaway. Palaeogeogr Palaeoclimatol Palaeoecol 2001;165:375–94. http://dx.doi.org/10.1016/S0 031-0182(0 0) 00172-3. [2] Alberti M, Fürsich FT, Pandey DK. The Oxfordian stable isotope record (δ ;18 O, δ ;13 C) of belemnites, brachiopods, and oysters from the Kachchh Basin (western India) and its potential for palaeoecologic, palaeoclimatic, and palaeogeographic reconstructions. Palaeogeogr Palaeoclimatol Palaeoecol 2012;344345:49–68. doi: http://dx.doi.org/10.1016/j.palaeo.2012.05.018 . [3] Arias C. Northern and Southern Hemispheres ostracod palaeobiogeography during the Early Jurassic: possible migration routes. Palaeogeogr Palaeoclimatol Palaeoecol 2006;233:63–95. doi: http://dx.doi.org/10.1016/j.palaeo.2005. 09.006 . [4] Bartolini A, Larson RL. Pacific microplate and the Pangea supercontinent in the Early to Middle Jurassic. Geology 2001;29:735–8. doi: http://dx.doi.org/ 10.1130/0091-7613(2001) . [5] Baumgartner PO, Matsuoka A. New radiolarian data from DSDP Site 534, Blake Bahama Basin, central Northern Atlantic. In: Baumgartner PO, et al., editors. Middle jurassic to lower cretaceous radiolaria of Tethys: occurrences, systematics, biochronology, 23. Lausanne, Switzerland: Memoires de Geologie; 1995. p. 709–15. [6] Baumgartner PO, et al. Middle Jurassic to Early Cretaceous radiolarian biochronology of Tethys based on Unitary Associations. In: Baumgartner PO, et al., editors. Middle jurassic to lower cretaceous radiolaria of Tethys: occurrences, systematics, biochronology, 23. Lausanne: Memoires de Geologie; 1995. p. 1013–43. [7] Beccaro P. Radiolarian correlation of Jurassic siliceous successions of the Rosso Ammonitico Formation in the Southern Alps and Western Sicily (Italy). Eclogae Geologicae Helvetiae 2006;99:S21–33. doi: http://dx.doi.org/10.1007/ s0 0 015-0 06-0607-0 . [8] Damborenea SE, Manceñido MO. On the palaeogeographical distribution of the pectinid genus Weyla (Bivalvia, Lower Jurassic). Palaeogeogr Palaeoclimatol Palaeoecol 1979;27:85–102. doi: http://dx.doi.org/10.1016/0031-0182(79) 90095-6 . [9] Damborenea SE. Hispanic Corridor: its evolution and the biogeography of bivalve mollusks. In: Hall RL, Smith PL, editors. Advances in jurassic research 20 0 0, 6. Geo Research Forum; 20 0 0. p. 369–80. [10] Damborenea SE, Echevarría J, Ros-Franch S. Southern Hemisphere palaeobiogeography of Triassic-Jurassic marine bivalves. Springer Briefs Seaways and Landbridges: Southern Hemisphere Biogeographic Connections Through Time; 2013. doi: http://dx.doi.org/10.1007/978- 94- 007- 5098- 2_1 . [11] Dera G, Neige P, Dommergues J-L, Brayard A. Ammonite paleobiogeography during the Pliensbachian–Toarcian crisis (Early Jurassic) reflecting paleoclimate, eustasy, and extinctions. Glob Planet Chang 2011;78:92–105. doi: http: //dx.doi.org/10.1016/j.gloplacha.2011.05.009 . [12] Dera G, Prunier J, Smith PL, Haggart JW, Popov E, Guzhov A. Nd isotope constraints on ocean circulation, paleoclimate, and continental drainage during the Jurassic breakup of Pangea. Gondwana Res 2015;27:1599–615. doi: http://dx.doi.org/10.1016/j.gr.2014.02.006 . [13] Doré AG. The structural foundation and evolution of Mesozoic seaways between Europe and the Arctic. Palaeogeogr Palaeoclimatol Palaeoecol 1991;87:441–92. doi: http://dx.doi.org/10.1016/0031-0182(91)90144-G . [14] Doyle P, Howlett P. Antarctic belemnite biogeography and the break-up of Gondwana. Geol Soc London Special Publ 1989;47:167–82. doi: http://dx.doi. org/10.1144/GSL.SP.1989.047.01.13 . [15] Geiger M. Reappraisal of the timing of the breakup of Gondwana based on sedimentological and seismic evidence from the Morondava Basin, Madagascar. J Afr Earth Sci. 2004;38:363–81. doi: http://dx.doi.org/10.1016/S0899-5362(04) 0 0 030-2. [16] Geiger M, Schweigert G. Toarcian–Kimmeridgian depositional cycles of the south-western Morondava Basin along the rifted continental margin of Madagascar. Facies 2006;52:85. doi: http://dx.doi.org/10.1007/s10347- 005- 0039- 8 . [17] Habib D, Drugg WS, et al. Dinoflagellate age of Middle Jurassic-Early Cretaceous sediments in the Blake-Bahama Basin. In: Sheridan RE, editor. Deep sea drilling project. Washington: U.S. Govt. Printing Office; 1983. p. 623–38. Initial Reports, v.76 http://dx.doi.org/10.2973/dsdp.proc.76.126.1983 . [18] Hallam A. Provinciality, diversity and extinction of Mesozoic marine invertebrates in relation to plate movements, in: Tarling DH, Runcorn, SK. (Eds), Implications of continental drift to the Earth sciences, Vol. 1. Academic Press, London, 1973; pp. 287–294. [19] Hallam A. Distributional patterns in contemporary terrestrial and marine animals, in: Hughes, NF, (Ed), Organisms and continents through time. Special Papers in Palaeontology 1973; 12:93–105. Available online at: http://cdn.palass.org/publications/special_papers_in_palaeontology/spp_12/ pdf/spp12_pp93-106.pdf. [20] Hallam A. Biogeographic evidence bearing on the creation of Atlantic seaways in the Jurassic, in: West, RM. (Ed), Paleontology and Plate tectonics: Proceeding of a Symposium presented at the North American Paleontological Convention
[23]
[24]
[25]
[26]
[27]
[28] [29]
[30]
[31]
[32]
[33]
[34]
[35]
[36]
[37]
[38]
[39]
[40]
[41]
[42]
[43]
[44]
65
II. Milwaukee Public Museum: Special Publication in Biology and Geology vol. 2; 1977, pp. 23–34. Hallam. Early and mid-jurassic molluscan biogeography and the establishment of the central Atlantic seaway. Palaeogeogr Palaeoclimatol Palaeoecol 1983;43:181–93. doi: http://dx.doi.org/10.1016/0031-0182(83)90010-X . Iturralde-Vinent M. Meso-Cenozoic Caribbean paleogeography: implications for the Historical Biogeography of the region. Int Geol Rev 2006;48:791–827. doi: http://dx.doi.org/10.2747/0020-6814.48.9.791 . Katz ME, Wright JD, Miller KG, Cramer BS, Fennel K, Falkowski PG. Biological overprint of the geological carbon cycle. Marine Geol 2005;217:323–38. doi: http://dx.doi.org/10.1016/j.margeo.20 04.08.0 05 . Klitgord KD, Schouten H. Plate kinematics of the central Atlantic. In: Vogt PR, Tucholke BE, editors. The geology of north America: the western north atlantic region, Vol. M. Boulder, CO: Geological Society of America; 1986. p. 351–78. Koppers AAP, Staudigel H, Duncan RA. High-resolution 40Ar/39Ar dating of the oldest oceanic basement basalts in the western Pacific basin. Geochem Geophys Geosyst 2003;4:11. doi: http://dx.doi.org/10.1029/20 03GC0 0 0574 . Labails C, Olivet J-L, Aslanian D, Roest WR. An alternative early opening scenario for the Central Atlantic Ocean. Earth Planet Sci Lett 2010;297:355–68. doi: http://dx.doi.org/10.1016/j.epsl.2010.06.024 . Longridge LM, Smith PL, Pálfy J, Tipper HW. Three New Species of the Hettangian (Early Jurassic) Ammonite Sunrisites from British Columbia, Canada. J Paleontol 2008;82:128–39. doi: http://dx.doi.org/10.1666/05-158.1 . Louis-Schmid B. Feedback mechanisms between carbon cycling, climate and oceanography. Zürich: Federal Institute of Technology ETH; 2006. Louis-Schmid B, Rais P, Bernasconi SM, Pellenard P, Collin P-Y, Weissert H. Detailed record of the mid-Oxfordian (Late Jurassic) positive carbon-isotope excursion in two hemipelagic sections (France and Switzerland): A plate tectonic trigger? Palaeogeogr Palaeoclimatol Palaeoecol 2007;248:459–72. doi: http://dx.doi.org/10.1016/j.palaeo.2007.01.001 . Ludden JN, Plank T, Larson R, Escutia C. Leg 185 synthesis: sampling the oldest crust in the ocean basins to understand Earth’s geodynamic and geochemical fluxes. In: Ludden JN, Plank T, Escutia C, editors. Proc. ODP, Sci. Results; 2006. p. 1–35. 185[Online]. Available from http://www-odp.tamu.edu/publications/ 185_sr/VOLUME/SYNTH/SYNTH.PDF . Martin-Garin B, Lathuilière B, Geister J. The shifting biogeography of reef corals during the Oxfordian (Late Jurassic). A climatic control? Palaeogeogr Palaeoclimatol Palaeoecol 2012;365–366:136–53. doi: http://dx.doi.org/10.1016/j. palaeo.2012.09.022 . Matsuoka A, et al. Jurassic and Early Cretaceous radiolarians from Leg 129, Sites 800 and 801, Western Pacific Ocean. In: Larson RL, Lancelot Y, et al., editors. 1992 Proceedings of the Ocean Drilling Program, Scientific Results; 1992. p. 203–20. Vol. 129. doi: http://dx.doi.org/10.2973/odp.proc.sr.129.121.1992 McInerney FA, Wing SL. The Paleocene-Eocene Thermal Maximum: a perturbation of carbon cycle, climate, and biosphere with implications for the future. Ann Rev Earth Planet Sci 2011;39:489–516. doi: http://dx.doi.org/10. 1146/annurev- earth- 040610- 133431 . Moyne S, Neige P, Marchand D, Thierry J. World distribution of middle Jurassic ammonites (Upper Aalenian to Middle Bathonian): relationships between biodiversity and palaeogeography. Bulletin de la Société Géologique de France 2004;175:513–23. doi: http://dx.doi.org/10.2113/175.5.513 . Nikitenko B, Shurygin B, Mickey MB. High resolution stratigraphy of the Lower Jurassic and Aalenian of Arctic regions as the basis for detailed palaeobiogeographic reconstructions. Norw J Geol 2008;88:267–78. Available at: http: //www.geologi.no/images/NJG_articles/NJG_Nikitenko_et_al_4_2008_print.pdf . Nunn EV, Price GD, Hart MB, Page KN, Leng MJ. Isotopic signals from Callovian–Kimmeridgian (Middle–Upper Jurassic) belemnites and bulk organic carbon, Staffin Bay, Isle of Skye, Scotland. J Geol Soc 2009;166:633–41. doi: http://dx.doi.org/10.1144/0 016-764920 08-067 . Ogg JG, Ogg G. Updated biochronostratigraphical chart of the Late Jurassic . (accessed on 20 November 2016) Available online at: doi: https://engineering. purdue.edu/Stratigraphy/charts/Timeslices/5_JurCret.pdf. Ogg JG, Hinnov LA. Chapter 26: Jurassic. In: Gradstein FM, Ogg JG, Schmitz MD, Ogg GM, editors. The geologic time scale 2012. Amsterdam: Elsevier; 2012. p. 731–91. doi: http://dx.doi.org/10.1016/B978- 0- 444- 59425- 9.0 0 026-3. Padden M, Weissert H, de Rafelis M. Evidence for Late Jurassic release of methane from gas hydrate. Geology 2001;29:223–6. doi: http://dx.doi.org/10. 1130/0091-7613(2001)0290223:EFLJRO203;2.0.CO;2 . Padden M, Weissert H, Funk H, Schneider S, Gansner C. Late Jurassic lithological evolution and carbon-isotope stratigraphy of the western Tethys. Eclogae Geologicae Helvetiae 2002;95:333–46. Available at: http://www.e-periodica. ch/digbib/view?pid=egh-0 01:20 02:95::359#359 . Parrish JT. Jurassic climate and oceanography of the Pacific region. In: Westermann GEG, editor. The jurassic of the circum-Pacific. London: Cambridge University Press; 1992. p. 365–80. doi: https://doi.org/10.1017/CBO9780511529375. 029. Rais P, Louis-Schmid B, Bernasconi SM, Weissert H. Palaeoceanographic and palaeoclimatic reorganization around the Middle–Late Jurassic transition. Palaeogeogr Palaeoclimatol Palaeoecol 2007;251:527–46. doi: http://dx.doi. org/10.1016/j.palaeo.20 07.05.0 08 . Riccardi AC. Jurassic and cretaceous marine connections between the Southeast Pacific and Tethys. Palaeogeogr, Palaeoclimatol, Palaeoecol 1991;87:155– 89. doi: http://dx.doi.org/10.1016/0031-0182(91)90134-D . Rogov MA. Ways of migrations and correlative potential of the Middle Oxfordian ammonites: new data from the Russian plate. In: Proceedings of
66
[45]
[46]
[47]
[48]
[49]
[50]
[51]
L. Brikiatis / GeoResJ 14 (2017) 59–66 the International Conference Paleobiogeography and Paleoecology 20 01; 20 02. p. 181–2. Rogov M, Zakharov V, Kiselev D. Molluscan immigrations via biogeographical ecotone of the Middle Russian Sea during the Jurassic. Volumina Jurassica 2008;6:143–52. Sahagian D, Pinous O, Olferiev A, Zakharov V. Eustatic curve for the Middle Jurassic–Cretaceous based on Russian Platform and Siberian Stratigraphy: zonal resolution. Am Assoc Pet Geol Bull 1996;80:1433–58. Saltzman MR, Thomas E. Chapter 11: Carbon Isotope Stratigraphy. In: Gradstein FM, Ogg JG, Schmitz MD, Ogg GM, editors. The geologic time scale 2012. Amsterdam: Elsevier; 2012. p. 207–32. doi: http://dx.doi.org/10.1016/ B978- 0- 444- 59425- 9.0 0 011-1. Sandy MR, Stanley GD Jr. Late Triassic brachiopods from the Luning Formation, Nevada, and their palaeobiogeographical significance. Palaeontology 1993;36:439–80. Available at: http://cdn.palass.org/publications/ palaeontology/volume_36/pdf/vol36_part2_pp439-480.pdf . Schettino A, Turco E. Breakup of Pangaea and plate kinematics of the central Atlantic and Atlas regions. Geophys J Int 2009;178:1078–97. doi: http://dx.doi. org/10.1111/j.1365-246X.2009.04186.x . Scotese CR. Atlas of Jurassic Paleogeographic Maps, PALEOMAP Atlas for ArcGIS, volume 3, The Jurassic and Triassic, Maps 32 - 42, Mollweide Projection, Evanston, IL: PALEOMAP Project; 2014. Technical Report. doi: http://dx.doi.org/ 10.13140/2.1.4850.4321 . Sheridan RE, Gradstein FM, et al. In: Sheridan RE, et al., editors. Site 534: blake-bahama basin. Washington: Deep Sea Drilling Project; 1983. p. 141–340. Initial Reports 76 doi: http://dx.doi.org/10.2973/dsdp.proc.76.104.1983.
[52] Sheridan RE, Gradstein FM, Barnard LA, Bliefnick DM, Habib D, et al. Early history of the Atlantic Ocean and gas hydrates on the Blake Outer Ridge: results of the Deep Sea Drilling Project Leg 76 Papers in the Earth and Atmospheric Sciences. Paper 257 http://digitalcommons.unl.edu/geosciencefacpub/257. [53] Smith PL. The Pliensbachian ammonite Dayiceras dayiceroides and Early Jurassic paleogeography. Can J Earth Sci 1983;20:86–91. doi: http://dx.doi.org/10. 1139/e83-008 . [54] Smith PL, Tipper HW. Plate tectonics and paleobiogeography: Early Jurassic (Pliensbachian) endemism and diversity. Palaios 1986;1:399–412. http://www. jstor.org/stable/3514477. [55] Smith. Paleobiogeography and plate tectonics. Geosci Can 1989;15:261–79. Available online at: https://journals.lib.unb.ca/index.php/GC/article/view/3575/ 4089 . [56] Stanley GD Jr. Late Paleozoic and Early Mesozoic reef-building organisms and paleogeography: the Tethyan-North American connection. Courier Forschungsinstitut Senkenberg 1994;172:69–75. [57] Venturi F, Bilotta M, Ricci C. Comparison between western Tethys and eastern Pacific ammonites: further evidence for a possible late Sinemurian–early Pliensbachian trans-Pangaean marine connection. Geol Mag 2006;143:699–711. [58] Westermann GEG. Global bio-events in mid-Jurassic ammonites controlled by seaways. In: House MR, editor. The Ammonoidea: Environment, ecology and evolutionary change. Oxford: Clarendon Press; 1993. p. 187–226. Systematics Association Special Volume Series 47.