Source rock characteristics and biostratigraphy of the Lower Silurian (Telychian) organic-rich shales at Akyaka, central Taurus region, Turkey

Varol O. N. , Demirel I. H. , Rickards R. B. , Gunay Y.

MARINE AND PETROLEUM GEOLOGY, cilt.23, ss.901-911, 2006 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 23
  • Basım Tarihi: 2006
  • Doi Numarası: 10.1016/j.marpetgeo.2006.07.003
  • Sayfa Sayıları: ss.901-911


The Akyaka section in the central Taurus region in the southern part of Turkey includes the organic matter and graptolite-rich black shales which were deposited under dysoxic to anoxic marine conditions in the Early Silurian. A biostratigraphical analysis, based on graptolite assemblages, indicates that the sediments studied may well be referable to the querichi Biozone and early Telychian, Llandovery. A total of 15 samples have been subjected to Leco and Rock-Eval pyrolysis and graptolite reflectance measurements for determination of their source rock characteristics and thermal maturity. The total organic carbon content of the graptolite-bearing shales varies from 1.75 to 3.52wt% with an average value of 2.86wt%. The present Rock-Eval pyrolytic yields and calculated values of hydrogen and oxygen indexes imply that the recent organic matter type is inert kerogen. The measured maximum graptolite reflectance (G(Rmax) %) values are between 5.04% and 6.75% corresponding to thermally over maturity. This high maturity suggests a deep burial of the Lower Silurian sediments resulting from overburden rocks of Upper Paleozoic to Mesozoic Upper Cretaceous and Middle-Upper Eocene thrusts occurred in the region. (c) 2006 Elsevier Ltd. All rights reserved.