Whole-rock Geochemistry of Gneiss from Thana, Bhilwara, India

Abstract

Gneiss is medium to high grade metamorphic rock present in one third part of Thana. These rocks have been formed by the metamorphism of pre-existing granites under medium to high P/T conditions and it consist essential minerals like quartz, k-feldspar, plagioclase, biotite, hornblende, epidote, garnet and iron-oxides. Geochemically, this gneiss is metaluminous in nature and similar to I-Type granite which is chemically similar to continental arc granitoids. It is also clear that they are formed by the highly fractionated magma. This paper records the petrography, geochemical character and probable origin of this gneiss.