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

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Mineral Chemistry of Biotites from Jalor, Tosham and JhunJhunu Ring Complexes: Malani Igneous Suite, India


Affiliations
1 PG Department of Geology, H.P. University, Regional Centre, Dharamsala, (H.P.) - 176 2 15, India
2 Department of Geology, Panjab University, Chandigarh, 160 014, India
3 HCC Ltd., C-1 Works, Tala Hydroelectric Project, PB# 390, Phuentsholing, Bhutan
 

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This paper describes mineral chemistry of biotites from Jalor, Tosham and Jhunjhunu ring complexes of Malani igneous suite, India. The chemistry reveals iron enrichment trend in all the biotite samples of the three complexes. FeO*/MgO ratio is the highest (6.72) in Jalor samples whereas lower values of (4.08) and (3.72) have been observed in Tosham and Jhunjhunu samples respectively. Higher MgO has not affected the enhanced proportions of FeO in the biotites of Tosham and Jhunjhunu. Mg ⇌ Fe and 2A1 ⇌ 3Fe2+ substitution is dominant in Jalor samples whereas, influence of 3M ⇌ Al is deciphered in the Tosham and Jhunjhunu samples. Most of the biotites fall in the anorogenic (A-type) suites, representing extensional tectonic environment for their host rocks.
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  • Mineral Chemistry of Biotites from Jalor, Tosham and JhunJhunu Ring Complexes: Malani Igneous Suite, India

Abstract Views: 191  |  PDF Views: 183

Authors

Sunil Dhar
PG Department of Geology, H.P. University, Regional Centre, Dharamsala, (H.P.) - 176 2 15, India
Naresh Kochhar
Department of Geology, Panjab University, Chandigarh, 160 014, India
Rajni Sharma
HCC Ltd., C-1 Works, Tala Hydroelectric Project, PB# 390, Phuentsholing, Bhutan
L. N. Gupta
Department of Geology, Panjab University, Chandigarh, 160 014, India

Abstract


This paper describes mineral chemistry of biotites from Jalor, Tosham and Jhunjhunu ring complexes of Malani igneous suite, India. The chemistry reveals iron enrichment trend in all the biotite samples of the three complexes. FeO*/MgO ratio is the highest (6.72) in Jalor samples whereas lower values of (4.08) and (3.72) have been observed in Tosham and Jhunjhunu samples respectively. Higher MgO has not affected the enhanced proportions of FeO in the biotites of Tosham and Jhunjhunu. Mg ⇌ Fe and 2A1 ⇌ 3Fe2+ substitution is dominant in Jalor samples whereas, influence of 3M ⇌ Al is deciphered in the Tosham and Jhunjhunu samples. Most of the biotites fall in the anorogenic (A-type) suites, representing extensional tectonic environment for their host rocks.