Sedimentological and geochemical properties of the Kindiralik dere formation, Gümüşhane, Türkiye

Sakarya Zone is one of the important components of the Alpine-Himalayan belt and has a controversial Mesozoic geodynamic evolution. The Upper Cretaceous sequences, which constitute the important products of Mesozoic geodynamics, are quite common in the eastern Sakarya Zone, and they show difference in lithology in the north-south line. The Upper Cretaceous sequences are represented by sedimantary rocks in the the south part of the Eastern Pontides (East part of the Sakarya Zone) and the most typical outcrops of the Upper Cretaceous sequences are located in the Gümüşhane region of the Eastern Pontides. In the Gümüşhane region, these sedimentary rocks are divided into three main lithostratigraphic units, from bottom to top, Kındıralık Dere, Elmalı Dere and Tepeköy Formations, according to their different lithofacies characteristics. Within the scope of the thesis, the Kındıralık Dere Formation, which is the first product of the basins formed by the Late Cretaceous rifting of the Late Jurassic-Early Cretaceous Berdiga Formation, was investigated. In this context, three measured stratigraphic sections were studied. Kındıralık Dere Formation shows different lithofacies features in vertical and lateral directions in Gümüşhane region. In petrographic examinations, it was determined that the sediments were mainly composed of monogenic conglomerate, calcarenite and sandstones. The components in the studied rocks are mostly composed of transported bioclast fragments. The sediments mostly formed on the basin slope. The predominant sandstone levels in the Kındıralık Dere Formation, especially in the Pirahmet section, were investigated geochemically within the scope of the thesis. It has been determined that the examined sandstones are composed of litharenite and sublitharenite. The studied samples have low SiO2 values and high CaO values in terms of their geochemical properties. TiO2 and Fe2O3+MgO values vary between 0.22-0.77 and 4.13-10.28, respectively. The U/Th ratios are between 0.28 and 0.35 (average 0.32), Ni/Co ratios are 0.58-1.35 (average 0.89), and V/Cr ratios are 1.49-2,46 (average 1.91) values. These values indicate oxic environments. The geochemical values of the studied samples are related to the products of an acidic and intermediate arc magmatism. Investigated samples were deposited on the slopes of asymmetrical basins, which were developed on the carbonate platform that broke up as a result of Late Cretaceous rifting event. The geochemical results show that the terrigenous fragments coming to the basin were derived from a magmatic arc.