ÇAĞRILI KONUŞMALAR / KEYNOTES Invited Speeches ... - TPJD

Carbon Isotope (δC13) Characteristics of Bituminous Shales in Middle
Miocene Hırka Formation (Beypazarı, Ankara / Turkey)
Berna Yavuz Pehlivanlı 1 , Şükrü Koç 2 , Ali Sarı 2
1 Bozok University Faculty of Engineering, Department of Geological Engineering, Yozgat
2 Ankara University, Faculty of Engineering, Department of Geological Engineering, Ankara
Studied samples were collected from bituminous shales of Middle Miocene Hırka Formation in
Beypazari Basin. These samples were rich in organic matter (2.08 to 48.48% TOC%) and the C13
isotope is very important delivered data for environmental review due to effective especially
biological processes of carbon isotopes. Carbon isotope data obtained from the study area ranged
from -24.6 ‰ to -33.52 ‰ (average ‰ -28,85). When samples have compared with δ13C datas
from various geological environments, it has also been identified to be similar with C-3 plants,
sedimentary rocks, metamorphic rocks and igneous rocks of in terms of samples distribution
ranges. C isotope fractions changes depending on temperature (Park and Epstein 1960). The
fractions are higher values in cold water plankton but on the contrary, it has less dissolved CO2
due to increase the effect solubility with temperature increase and therefore C isotopes shows
the lowest values. When we have considered the origin and the physicochemical conditions of
C-3 plants, it can be concluded to occure in terrestrial environment and in the warm waters of
Hırka formation bituminous shales in Beypazari basin.
Keywords: Beypazarı Basin, Hırka Formation, bituminous shale, the C isotope fractions (δ13C),
C-3 plants, terrestrial origin
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