Provenance, tectonic setting and depositional environment of the Paleo-proterozoic Gulcheru Formation, Cuddapah Basin, Southern India—clues

Autor: Saurav Jana, Debasish Shome, Gopal Chakrabarti
Rok vydání: 2021
Předmět:
Zdroj: Journal of Sedimentary Environments. 6:513-530
ISSN: 2447-9462
2662-5571
DOI: 10.1007/s43217-021-00059-2
Popis: The Paleo-proterozoic Gulcheru Formation (30–200 m thick) of Papaghni Group overlying Archean basement rocks of Proterozoic Cuddapah Basin, India is composed of conglomerate at the bottom overlain by extensive quartzite with grey shales as interbeds. Major oxides, trace and rare earth element (REE) elemental abundance gives significant information about (a) source rock including paleo-environment condition, (b) tectonic setting during deposition of sediments and (c) condition of deposition of the sediments. The high Chemical Index of Weathering (CIW) [average 97], Plagioclase Index of Alteration (PIA) [average 95] values of the Gulcheru shales suggest strong chemical weathering processes of the source rock. The Al2O3/TiO2, TiO2/Ni ratio, LREE/HREE ratios with negative Eu anomaly and Cu/Zn, Ni/Co,U/Th and V/Cr ratio indicate a mixed felsic igneous provenance which seems to be derived from Dharwarian Granite Gneiss. The geochemical components of V, Cr, Ni, Co, U and Th strongly suggest that these clastic rocks are deposited in an oxic condition. The discrimination plot La-Th-Sc and Th-Sc-Zr/10 suggest that the Gulcheru clastic sediments were deposited in continental island arc setting during the process of amalgamation of supercontinent Columbia. This back-arc extensional basin was formed due to the subduction of the oceanic crust underneath the Dharwar Craton. These findings have significant implications for the study about the paleo-geology of Cuddapah Basin, especially paleo-climate of Gulcheru Formation in which there are limited previous work.
Databáze: OpenAIRE
Externí odkaz: