| mhorn | Дата: Friday, 12.10.2012, 23:32 | Сообщение # 1 |
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| Karakitsios V., Kafousia N., Tsikos H. (2010) A Review of Oceanic Anoxic Events as recorded in the Mesozoic sedimentary record of mainland Greece // Hellenic Journal of Geosciences, vol.45, P. 123-132.
pdf: http://www.hellenjgeosci.geol.uoa.gr/45/Karakitsios%20et%20al.pdf
This paper presents an overview of the salient biostratigraphic, isotopic and organic geochemical characteristics of the four most wellestablished Oceanic Anoxic Events (OAEs) of the Mesozoic era, as recorded in sedimentary sections from the Ionian and Pindos zones of the western Hellenides, Greece. The Toarcian OAE in the Kastelli section of the Pindos Zone is expressed through the characteristic negative carbon isotope excursion in bulk carbonate, near the base of the corresponding organic-rich interval. Carbonate-free, radiolarian-rich black shales of the Lower Aptian Fourcade level from the Paliambela section in the Ionian zone, record a negative bulk organic carbon isotope spike at their base, typical of OAE 1a black shales elsewhere. The Early Albian OAE 1b is faithfully recorded in the stratigraphically uppermost black shale layer of the Aptian-Albian “Vigla Shale Member” of the Ionian Zone, with its characteristic molecular organic geochemical and isotopic signatures indicative of partly archaeal derivation for the organic matter. Finally, a thin and highly TOC-enriched black shale layer at the Cenomanian-Turonian boundary within the Vigla limestone succession of the Ionian Zone, is interpreted to represent a condensed stratigraphic equivalent to the Livello Bonarelli, the type locality of OAE 2 in Italy, on the basis of isotopic and organic geochemical results. The above records provide new insights into current debates concerning the forcing mechanisms of, and palaeoclimatic responses during OAEs, and constitute an important benchmark for future research on the manifestation and palaeoenvironmental significance of Mesozoic OAEs in mainland Greece
Middle Jurassic - Lower Cretaceous ammonites & aptychi
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