Source Rock Potential and Tectonic Effect on the Regional Maturity on the Central Taurus Region, SW Turkey: New Exploration Targets

Abstract

The central part of the Taurus Belt in SW Turkey comprises thick paraoutochthonous carbonates and clastics of Mesozoic and Tertiary ages. The source rock potential of Mesozoic and Tertiary units in the area between Beysehir and Akseki has been investigated by standard laboratory studies (total organic carbon (TOC) analysis, oil show pyrolysis, and organic petrography). These analyses show that the Tarasç L Formation (Triassic), the Üzümdere Formation (Lower Jurassic), the Ayd L nkent Formation (Upper Cretaceous-Middle Eocene), and the Gümüs¸damla Formation (Middle Eocene) have no source rock potential. However, the Akkuyu Formation (Upper Jurassic to Lower Cretaceous) is a variable but important source rock where the formation is influenced by allocthonous rocks; it shows lower TOC, lower genetic potential, and lower HI values than other exposures not effected by nappe tectonism in the study area. Where it crops out in the North, the formation has reacted high thermal maturity (477-569°C), but in the South, it is immature to mature (425-433°C) where it is not effected by the nappe activity. Similar results were obtained for the Gümüs¸damla Formation - that is, tectonic contact of upper boundary with nappe. These results suggest that the variable organic geochemical properties and maturity of the Akkuyu and Gümüs¸damla Formations may be related to the tectonic history of the study area. Also, they suggest that Mesozoic carbonates underlaying the allocthonous units may form important source rocks and structural trap. However, the absence of detailed geophysical data and the lack of exploration wells are a major barrier to the study of the area, considering the presence of hydrocarbon producing source and reservoir rocks. Detailed studies directed toward determining structural traps below the allocthonous should be undertaken in the future.