Geochemical characterization of the siliciclastic rocks of Chitravati Group, Cuddapah Supergroup: Implications for provenance and depositional environment

Abstract

Petrological and geochemical studies have been carried out on Pulivendla and Gandikota Quartzite from Chitravati Group of Cuddapah Supergroup to decipher the provenance and depositional environment. Both the units are texturally mature with sub-rounded to well-rounded and moderately to well-sorted grains. Majority of the framework grains are quartz, in the form of monocrystalline quartz, followed by feldspars (K-feldspar and plagioclase), mica, rock fragments, heavy minerals, with minor proportion of the matrix and cement. Based on major element geochemical classification diagram, Pulivendla Quartzite is considered as quartz-arenite and arkose to sub-arkose, whereas Gandikota Quartzite falls in the field of lith-arenite and arkose to sub-arkose. Weathering indices like CIA, PIA, CIW, ICV, Th/U ratio and A-CN-K ternary diagram suggest moderate to intense chemical weathering of the source rocks of these quartzites. Whole rock geochemistry of quartzites indicate that they are primarily from the first-cycle sediments, along with some minor recycled components. Also their sources were mostly intermediate-felsic igneous rocks of Archean age. The tectonic discrimination plots, Th-Sc-Zr/10 of both these formations reflect active to passive continental margin setting. Chondrite-normalized rare earth element (REE) patterns, and various trace element ratios like Cr/Th, Th/Co, La/Sc and Th/Cr indicate dominantly felsic source with minor contribution from mafic source. Th/Sc ratios of Pulivendla and Gandikota Quartzite are in close proximity with average values of 2.83, 3.45 respectively, which is higher than AUCC (Th/Sc = 0.97), demonstrating that the contributions from more alkali source rocks than those that contributed to AUCC.

Cuddapah Basin, India: A Collage of Proterozoic Subbasins and Terranes

“…These beds can be continuously traced across long distances along their strike, further indicating their deposition along a sandy shore-line under the influence of long-shore and tidal currents. Somasekhar et al (2018) have inferred that these siliciclastics have been derived from an Archean crust and deposited in a passive margin environment based on their chemical characterisation.…”

Geochemistry of the Palaeoproterozoic quartzites of Lower Cuddapah Supergroup, South India: Implications for the palaeoweathering, provenance, and crustal evolution

“…Basic dykes are emplaced along some of the ENE‐WSW to ESE‐WNW trending faults (Basu, Mahendra Kumar, Paneerselvam, & Chaki, ). In Pulivendla Formation, primary sedimentary structures such as asymmetrical ripples are common (Somasekhar, Ramanaiah, & Sarma, ; Saha & Tripathy, ). The Pulivendla Formation was deposited in a high‐energy shallow subtidal environment (Mackintosh, ).…”

Geochemical Speciation and Batch Mode Simulation in the Carbonate Depositional Environments

“…The scientific community has progressed in geochemical modeling for both natural and hypothetical environments (Manoj et al, 2019;Johnson et al, 2018;Fowler et al, 2018;Somasekhar et al, 2018;Singh et al, 2017). These developments are associated with numerical techniques, which are capable of solving complex mathematical problems, along with incorporating improvements in evaluating capability of computers (Singh et al, 2017).…”