Phyllosilicate/Clay Geochemistry of Mineralogy and Upper Cretaceous-Paleocene Germav Formation in Mardin-Dargecit Area

Abstract

In this study, it is aimed to determine the mineralogical and geochemical features of the rocks from the Germav Formation of Upper Cretaceous-Paleocene age belonging to Sirnak Group. The clastic and chemical originated rocks of the unit show different grain size, mineralogical composition and textural relations as epiclastic (sandstone, sandstone with carbonate), pelitic (shale) and clayey-sandy carbonate (marl, sandy limestone). Rock forming minerals determined by XRD; in the order of abundance calcite, phyllosilicate /clay (chlorite, C-S, C-V, vermiculite, illite, rarely serpentine, I-C and I-V), quartz, feldspar, dolomite, hematite and goethite. According to the results of OM, SEM and XRD examinations in the unit; there are also detrital minerals transported from metamorphic and ophiolitic units as well as diagenetic minerals. The phyllosilicate /clay minerals with different chemical composition are rich in Al2O3, tFe(2)O(3) and/or MgO. Trace element and REE concentrations are mostly observed in chlorite and least in vermiculite mineral. The contents of phyllosilicate /clay minerals when compared with the chondrite values; the patterns of the samples are distinct from each other, although the enrichments-depletions vary on the basis of the derived rocks, minerals and elements. Phyllosilicate /clay minerals exhibit significant variation /differentiation /partition according to the chondrite and NASC compositions in terms of trace and REE contents.