Abstract
The study is carried out on twenty shale samples that were collected from the Kolosh Formation (Paleocene – Early Eocene) within the Dokan area at northeastern part of Iraq. The samples were subjected to laboratory studies including chemical analyses for origin rock characterizing source rock composition, paleo-weathering conditions and tectonic. The origin rock compositions were evaluated mainly based on Al2O3/TiO2, TiO2/Zr ratios and a TiO2 and Al2O3bivariate. The result suggest predominantly intermediate igneous source rock of the Kolosh Formation shale’s. The bivariate plot, of (K2O/Na2O) and (SiO2), (MgO+Fe2O3 %) and (TiO2%), as well as the refashion ships based on the elemental components (Co ,Th, Sc, Zr, La) were used to reveal tectonic setting of the depositional basin. All Kolosh Formation shale’s samples were in Oceanic Island Arc. CIA values, bivariate plot of (SiO2%) and (Al2O3+Na2O3+K2O)% and ) (Al2O3- CaO+Na2O- K2O) %compositional space of the shale samples were utilized to infer the chemical maturity and the pale weathering conditions of the Formation. The results shows that Kolosh shale samples represent lower degree of chemical weathering of origine rock which imply semi-arid climatic conditions. .
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