Silurian-Devonian Boundary In Se Anatolia (3): An Organic-Geochemical Assignment For Positioning Of The Boundary At The Hazro Area

Abstract

In the Hazro area of the Turkish border fold zone in SE Anatolia (Fig. 1), the exact position of the Silurian-Devonian (S-D) boundary is still under debate. Biostratigraphic approaches failed up to now (compare Luppold et al., 2012, this meeting: Silurian-Devonian Boundary 2) due to several missing index fossils (e.g. graptolites), revision of index fossils (conodonts) and a partly incomplete distribution of palynomorphs (e.g. chitinozoans and acritarchs). According to the geological information from this area near the north rim of the Arabian plate, the SD boundary should be positioned within the local Upper Dadas Fm. which represents a subunit of the Silurian to Devonian Diyarbarkir Group (Bozdogan et al, 1987; Fontaine et al., 1980). Based on Acritarch assemblages, the Dadas Fm. is of Wenlockian to Lochkovian age (Bozdogan and Ertug, 1997).