Remnants of Supracrustal Rocks around Mohar Brecciated Granite Complex, Shivpuri District, Madhya Pradesh: A Petrological and Geochemical Appraisal

Abstract

Enclaves, pockets, slivers and lenses of dark colored rocks within the predominantly granite territory and commonly referred to as andesites, have been reported in the area around Mohar structure in the western parts of Bundelkhand craton. These rocks are characterised by diverse mineralogy, microfabric and geochemical signature, although apparently maintaining similarity in broad megascopic attributes. Compositionally, these rocks deviate markedly from average andesite. The concerted petrological and geochemical studies have revealed three major rock suites viz., (a) tonalite-trodjhemite-granodiorite (TTG) mylonite gneisses, (b) calc-silicate-aluminous tuffaceous sediment association and (c) meta-rhyodacite porphyry. All the rocks are characterized by an imprint of dynamothermal metamorphism leading to the invariable development of a discernible gneissose fabric. The study also implies that these rocks in all their diversity, represent part of the metamorphosed and deformed supracrustals, surviving as remnants within younger Bundelkhand granitoid pluton, thereby stratigraphically older.