Yahşihan (Kırıkkale) Bölgesindeki Sedimanter Birimlerin Mineralojik ve Jeokimyasal Özellikleri

Abstract

In the Yahşihan (Kırıkkale) sedimentary basin, Upper Cretaceous - Pliocene aged sedimentary and magmatic units outcrop. The units examined within the scope of this thesis are the Karadağ formation, Samanlık formation, Çiçekdağ formation, Central Anatolian Granitoids, Kuşkayatepe Limestone Olistolite, Dizilitaşlar formation, Çayraz formation and İncik formation. The mineralogical compositions of the samples taken from the units, according to X-ray diffraction analyses, consist of mica, clay, calcite, dolomite, quartz, feldspar, gypsum, analcime, serpentine and kaolinite minerals. Among the zeolite minerals, only analcime was identified in the thesis field and analcime is a secondary formation from pore water; it is thought that illite and chlorite, the most common clay minerals, are probably of detrital origin, while smectite was formed by the hydrolysis of volcaniclastic material. It was concluded that the corensite formations were hydrothermal corensite. Geochemical analysis data are used in the interpretation of provenance of sedimentary units in the study area shows that they are not derived from a homogeneous source and indicates a largely felsic magmatic and a certain amount of mafic origin. Th-Sc-Zr/10 tectonic environment discrimination diagram shows that a significant portion of the samples fall in the oceanic island-arc region. Beside these, U/Th and Ni/Co element ratios show that oxic paleoenvironmental conditions are generally dominant in the study area, anoxic and suboxic paleoenvironmental conditions are dominant in the deposition of Dizilitaşlar and İncik formations. The finding that reducing paleoenvironmental conditions exist for Dizilitaşlar and İncik formations is also supported by the detection of organic material formation in SEM images in Dizilitaşlar formation. In terms of paleoclimatic conditions, both humid and dry seasons are characteristic for the study area.