Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Sumana Dasgupta ¹, Jyotisankar Ray ¹, Abhijit Mazumder ¹, Niroj K. Sarkar ², Sumita Das ¹, Chandrani Dasgupta ¹

Affiliations
1 Department of Geology, Calcutta University, 35, Ballygunge Circular Road, Calcutta 700 019, IN
2 59/3, Tatipara Lane, Howrah, West Bengal, IN

Abstract

The porphyritic granite bodies occurring around Raghunathpur have been studied petrographically to find out correlation characteristics among several mineralogical parameters with the help of systematic grid-sampling and modal analyses. Q-A-P diagram clearly suggests that the porphyritic granite bodies belong either to tondite or quartz-rich granitoid. The quartz-rich granitoids of porphyritic granite bodies are found to have distinct spatial control. Average mineralogical composition of porphyritic granite bodies and nature of correlation amongst significant parameters have been worked out following statistical procedures. The correlations among different mineralogical parameters however, yield poor values indicating the effects of assirnilation/granitisationlmagma mixing. A fair degree of silica enrichment, imposed on the crystallising magma parental to the porphyritic granite, has been suggested for its genesis, which is also corroborated by textural evidences.

Keywords

Porphyritic Granite Bodies, Correlation Characteristics, Mineralogy, Petrogenesis, Purulia, West Bengal.

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