∆İȜτȓο τȘȢ ΕȜȜȘȞȚțȒȢ ΓİωȜογȚțȒȢ ΕταȚȡȓαȢ, τοȝ. XLVII , 2013 ΠȡαțτȚțά 13 ου ∆ȚİșȞούȢ ΣυȞİįȡȓου, ΧαȞȚά, Σİπτ. 2013 Bulletin of the Geological Society of Greece, vol. XLVII 2013 Proceedings of the 13 th International Congress, Chania, Sept. 2013 CHEMOSTRATIGRAPHY OF THE TOARCIAN OCEANIC ANOXIC EVENT FROM THE IONIAN ZONE, GREECE Kafousia N. 1 , Karakitsios V. 1 , Mattioli E. 2 , and Jenkyns, H. C. 3 1 National and Kapodistrian University of Athens, Faculty of Geology and Geoenvi- ronment, Department of Hist. Geology - Paleontology, nkafousia@geol.uoa.gr, vkarak@geol.uoa.gr, 2 Laboratoire de Géologie de Lyon UMR 5276 CNRS, Université Lyon 1, ENS Lyon, Campus de la Doua, Bâtiment Géode, F-69622 Villeurbanne Cedex, France, eman- uela.mattioli@univ-lyon1.fr 3 Department of Earth Sciences, University of Oxford, South Parks Road OXFORD OX1 3AN, United Kingdom, Hugh.Jenkyns@earth.ox.ac.uk Abstract A global perturbation in the carbon cycle has been recorded in the Early Toarcian (~ 183 Ma) and is marked by enhanced organic-carbon burial and mass extinction. It is also associated with high palaeotemperatures, both positive and negative ex- cursions in carbon-isotope ratios, and the development of anoxic to euxinic condi- tions in marine environments: together these phenomena have been designated as constituting an Oceanic Anoxic Event. Here we provide a high-resolution, multi- proxy biostratigraphic and chemostratigraphic study from a section that belongs to the central Ionian Zone in Greece. Calcareous nannofossil distribution, as well as the TOC, į 13 C carb and į 13 C org , have all been determined. The nannofossil zones NJT 5b, NJT 6 and NJT 7 have been recognized in the section. In the NJT 5b zone a small positive excursion in TOC and negative excursion in į 13 C carb is recorded, ten- tatively assigned to the Pliensbachian/Toarcian boundary. In the NJT 6 zone, the main negative carbon-isotope excursion characteristic of this interval is developed, associated with a relative increase in TOC. The difference in this section, compared with sections from the Pindos Zone but in common with sections elsewhere, is the record of a positive excursion in the NJT 7 zone in both organic and carbonate car- bon isotopes. This study offers new biostratigraphic and geochemical data for the Ionian Zone, and further illustrates the impact of Toarcian Oceanic Anoxic Event in the Tethyan region. Key words: Jurassic, total organic carbon, carbon isotopes, biostratigraphy, geo- chemistry ΠİȡίȜηψη αIJΪ IJβ įδΪλεİδα IJκ αIJυIJİλκ ΣκΪλıδκ (~ 183 Ma), Ϋξİδ εαIJαΰλαφİέ ηδα αΰεσ- ıηδα αθαIJαλαξά ıIJκθ ετεζκ IJκ Ϊθγλαεα, β κκέα Ϋξİδ ıβηαįİIJİέ ασ ατιβıβ ıIJκθ λγησ İθIJαφδαıησ IJκ κλΰαθδεκτ Ϊθγλαεα εαδ ηααδεΫμ İιαφαθέıİδμ İδįυθ. Eέıβμ, Ϋξİδ ııξİIJδıIJİέ ασ οβζΫμ αζαδκγİληκελαıέİμ, γİIJδεΫμ εαδ αλθβIJδεΫμ ηİIJαίκζΫμ ıIJα δıσIJκα IJκ Ϊθγλαεα εαδ ηİ IJβ įβηδκλΰέα αθκιδευθ Ϋπμ İιδθδευθ ıθγβευθ ıIJα γαζΪııδα İλδίΪζζκθIJα. Ο ıθįαıησμ σζπθ αIJυθ IJπθ φαδθκηΫθπθ γİπλİέIJαδ