Petrological evolution and emplacement of siwana and jalor ring complexes of Malani Igneous suite, northwestern Peninsular India

Abstract

The Siwana and Jalor Ring Complexes of Malani Igneous suite,-northwestern Peninsular India consist predominantly of acid magmatic rocks with minor amount of basic rocks. The Siwana Ring Complex (SRC) has mainly acid volcanic and acid volcano-plutonic associations in northern and southern flank respectively. Acidic dyke rocks trending NE-SW directions cut these rocks. The Jalor Ring Complex (JRC) has mainly acid plutonic rocks and cut by numerous dolerite dyke rocks. The granites in Siwana are hypersolvus, alkali amphibole-alkali pyroxene-bearing, peralkaline (mildly peraluminous) in character whereas the granites of Jalor are subsolvus, mica-bearing, peraluminous (mildly peralkline) in character. The granites show a high abundance of aluminum, calcium, magnesium in Jalor and sodium, potassium in Siwana areas. The elements of LIL, HFS, REE groups in the granites of Siwana show enriched pattern as compared to Jalor. Both complexes show low oxygen and Pb radiogenic isotope values. Petrogeochemical studies define them as A-type, anorogenic, HHP magmatism in the trans-Aravalli region and were formed by low degree partial melting of parent stock of acid crust rock due to underplating of mantle material via plume activity. © 2011 Springer Science+Business Media B.V.