ORGANIC FACIES VARIATION FROM WELL DATA ON THE COALY PLIOCENE UNITS, THE CENTRAL PART OF TURKEY (KARAPINAR-KONYA)

Abstract

Some 100 core samples of coal and coaly units from the Pliocene succession (Hotamis Formation) were collected from well KK-147, in the southern part of Central Turkey (Karapinar-Konya). 30 samples were screened for total organic carbon (TOC) content. Selected samples were then analyzed by Rock-Eval Pyrolysis. Visual kerogen analysis and vitrinite reflectance measurements were also undertaken. Detailed data from thick Pliocene sediments made it possible to construct an organic facies framework using different zonations. Organic facies type C, CD and D were identified in the investigated units. The main composition in the organic matter of the sediments are woody (80%), with minor portions of planty (8%), amorphous (6%) and coaly (6%) in the investigation well. Alteration colors of these materials are yellow and dark yellow. Spore colors of these samples are yellow and dark yellow (SCI: 3-4). Organic facies C is related to clayey-sandy coal and coal lithofacies. This facies is composed of organic matter with average values of HI around 144 (equivalent to Type II/III Kerogene), TOC around 15.94 and S2 between 11.98 and 30.10 mg HC/g sample. Organic facies C is the "gas-prone" facies. The organic matter is dominated by terrestrial debris in various stages of oxidization. Sediments of organic fades C were commonly deposited on Tertiary and Mesozoic shelves and slopes of the continantel margins. Most coals are organic facies C. The organic faces CD is related to the clayey coal, coal and claystone lithofacies. This facies is characterized by average values of HI around 89 (equivalent to Type III Kerogene), TOC around 15.7%, and an average of S2 of 15.18 mg HC/g of rock. The CD facies reflects a mixture of source materials including terrestrial plant detrius, reworked and fine grained amophous organic matter. An organic facies D, associated with the coal, claystone, clayey limestone lithofacies, displays values of H1 around 26 (equivalent to Type III Kerogene) and TOC around 1.17%. S2 varies between 0.03 and 1.87 mg HC/g of rock. The D facies consists of highly decomposed, reworked organic matter. These types of organic facies generally appear to be weakly sorted in marine and lake sediments.