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Authors
Affiliations
1 Department of Geology, Aligarh Muslim University, Aligarh 202 002, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 35, No 6 (1990), Pagination: 620-630
Abstract
The granite is fine-to coarse-grained and constitutes mainly of quartz; K-feldspar and plagioclase. Among accessories, muscovite, biotite, chlorite, zircon, apatite and sphene are common. K-feldspar is generally microcline with perthitic intergrowth. The albite grains have similar optical orientation as that of the microcline; they are inferred to have formed by the ionic exchange of K by Na. The rock ranges in composition from granodiorite to granite. Variation trends of the plots of major and trace elements on Harker's diagram indicate that the granite is not formed by a simple fractional crystallization or partial melting of common homogeneous source. Plots on Rb, Ba and Sr ternary diagram reveal that it is a least differentiated normal granite type. Molar concentration of Al/(Na+K+Ca) > 1.1 and Rb/Sr ratio of 0.53 indicate a peraluminous source of the granitic magma. High silica content, and the mineral assemblages of the granite correspond to S-type granite.
Keywords
Ahar Granite, Geochemistry, Petrography (Igneous), Rajasthan.
