Abstract

This paper reports new mineral and whole-rock geochemical data on the acid volcano-plutonic rocks of the Tusham Ring Complex (TRC) from the Neoproterozoic Malani Igneous Suite (MIS), northwestern Peninsular India and discusses their magmatic evolution, tectonic implication, and geodynamic history. Geochemically, the investigated rocks have the characteristics of hypersolvus, high-K calc-alkaline to shoshonitic, peraluminous and A-type granitoids and they are enriched in SiO₂, (Na₂O + K₂O), Fe/ Mg, Ga/Al, Th, U, REE (except Eu), LILE + HFSE, halogens (F and Cl) and depleted in CaO, MgO, Sr, Cr, Ni, P, Ti and Eu abundances. They also show high heat production (HHP) affinity and high mineralization potential. The high abundances of fluorine (0.80–7.11 wt %) and chlorine (0.44–1.56 wt %) in biotite and the geochemistry of the studied rock types indicate that the acid volcanics and granite massifs of TRC were derived from a halogen-enriched magmatic source under low degree partial melting of crustal protolith. The field, petrography, mineral chemistry, whole-rock geochemistry of the rocks under study, in combination with their tectonic and petrogenetic signatures have proposed that the rift-related Neoproterozoic magmatism of MIS has close linkage with geodynamic evolution of Nagarparkar, Seychelles and Madagascar A-type granitoids during Rodinia breakup.

中文翻译：

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新元古代Malani火成岩套件及相关岩石的岩石学和地球化学综述（印度西北半岛）

摘要

本文报告了印度西北半岛新元古代Malani火成岩套件（MIS）的Tusham环复合体（TRC）的酸性火山-深成岩的新矿物和全岩石地球化学数据，并讨论了它们的岩浆演化，构造意义和地球动力学历史。从地球化学上讲，所研究的岩石具有高溶质，高钾钙碱性至生铁质，过铝质和A型花岗岩的特征，并且富含SiO ₂，（Na ₂ O + K ₂O），Fe / Mg，Ga / Al，Th，U，REE（Eu除外），LILE + HFSE，卤素（F和Cl）以及贫CaO，MgO，Sr，Cr，Ni，P，Ti和Eu的丰度。它们还显示出高产热（HHP）亲和力和高矿化潜力。黑云母中氟（0.80–7.11 wt％）和氯（0.44–1.56 wt％）的高丰度以及所研究岩石类型的地球化学表明，TRC的酸性火山岩和花岗岩块体来自富含卤素的岩浆源。地壳原生质的低度部分融化。所研究岩石的场，岩相学，矿物化学，全岩石地球化学，结合其构造和岩石成因特征，提出了与裂谷有关的新元古代岩浆作用与Nagarparkar的地球动力学演化密切相关，