Organic Geochemistry of Tanjero Formation at Dokan and Shaqlawa, Northern Iraq

Abstract

Late Campanian - Maastrichtian Tanjero Formation at Dokan and Shaqlawa areas was studied to determine its hydrocarbon-generation potential and depositional environment conditions. For this purpose, seventeen samples were subjected for Total Organic Carbon (TOC) and Rock-Eval pyrolyis analyses. Bitumen was extracted from three samples and analyzed by GC-FID.

Generally, TOC and S2 values of Tanjero Formation are low (0.07-0.54 and 0.01-0.53; respectively); indicating they have low potentiality for hydrocarbon generation. Rock-Eval pyrolysis parameters (hydrogen index, oxygen index, and Tmax) indicate that the Tanjero Formation clastics contain mainly type IV and III kerogen. Pristane/phytane values indicate that the Tanjero Formation was deposited under oxic environment. Weathering (especially oxidation) reduced the TOC, the potentiality of the formation rock, and the Extractable Organic Matter (EOM) values.