Provenance, petrographic and geochemical signatures of sandstones in Çalarasın Formation: A unit of ophiolitic melange in eastern of Kargı District


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YALÇIN C., HANİLÇİ N., KUMRAL M., KAYA M.

Engineering Applications, vol.1, no.2, pp.145-156, 2022 (Peer-Reviewed Journal)

  • Publication Type: Article / Article
  • Volume: 1 Issue: 2
  • Publication Date: 2022
  • Journal Name: Engineering Applications
  • Page Numbers: pp.145-156
  • Istanbul Technical University Affiliated: Yes

Abstract

Tectonic slices of different origins are observed in the eastern of Kargı (Çorum) district. These slices' metamorphic units and lithologies of ophiolitic melange are observed with tectonic contact. The Çalarasın formation is observed at the upper levels of the ophiolitic mélange, which extends to the east of Kargı (Çorum) in the Central Pontides. The formation is composed of thin-bedded siltstone intercalated sandstone-shale and mudstone alternations. The sandstones of the formation include quartz, plagioclase, calcite, biotite, chlorite, and volcanic rock particles. The sandstones were analyzed for geochemical properties and provenance traces, respectively. According to these analyzes, SiO2 % is found between 26.46-71.78%, Al2O3% 5.22-10.86, Fe2O3% 2.89-7.11 and CaO% 6.13-36.02 respectively. When trace elements are evaluated, Sc content ranges from 76.13-201.03 ppm, and Y content ranges from 9.54-55.11 ppm. Sandstones are rich in large ion lithophile elements (LIL; Ba, Th, U) and poor in high-field strength elements (HFS; Nb, Ti, Zr). Positive anomalies in terms of Pb and Y and negative ones in terms of Eu and P are observed in rocks. The sandstones are poor in terms of REE. The amount of HREE is substantially richer than the amount of LREE. Sandstones were normalized according to PAAS, and a distribution inversely proportional to the primitive values emerged. Ce/Ce* anomaly displays that the same oxygen environment has existed in the environment for a long time, but this situation has changed in the transition zone. Major oxide values suggest that the environment is arid and semi-arid media. It was determined that the sandstones were fed from the intermediate and mafic magmatic sources and tectonically represented the active continental margin and the island arc area.