Volume : V, Issue : VIII, August - 2016

Shale Geochemistry from Kolhan Basin: tectonic implications

Kasturi Bhattacharyya, Subhasish Das

Abstract :

 An integrated provenance analyses were carried out for the Proterozoic Kolhan, in which the petrographic features of the sandstones (quartz arenite–subarkose) and the geochemical characteristics of shales were used to understand the paleotectonic and provenance histories. The petrographic features imply a source area dominated by granites and granitoid gneisses, tectonic quiescence and peneplain topography. The Kolhan shales are dominated by illite, quartz, and fine crystalline dolomite; the average chemical index of alteration (CIA) for Kolhan shale is 71.8, and indicative of a granitoid source with a modest amount of chemical weathering. High Al2O3/SiO2 and K2O/Na2O ratios reflect a derivation of sediments from stable cratons during tectonic quiescences; the sandstones indicate an arid–semiarid climate with low chemical weathering, whereas the shales are indicative of a modest amount of chemical weathering. This discrepancy is due to transport segregation that accounts for the high percentage of shale in the basin. The Al2O3/SiO2 and K2O/Na2O ratio do indicate that the clastics were deposited in a passive margin/cratonic margin.

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Article: Download PDF   DOI : 10.36106/ijsr  

Cite This Article:

Kasturi Bhattacharyya, Subhasish Das Shale Geochemistry from Kolhan Basin: tectonic implications International Journal of Scientific Research,Volume : 5 | Issue : 8 |August 2016

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