Calc-Silicate Skarns from Chinnabantupalli, Srikakulam District, Andhra Pradesh

Calc-granulites of Chinnabantupalli area, Srikakulam district were subjected to contact metasomatism by the injection of K-feldspar-forming fluid. This paper describes the mineralogy of the calc-silicate skarns, mineral chemistry of clinopyroxene and garnet, and emphasizes the textural aspects which have a bearing on the genesis of skarn minerals. The minerals like wollastonite, hornblende, biotite, epidote-clinozoisite-zoisite, a part of the scapolites, garnets and calcites were secondarily formed as a result of contact metasomatism. Most of the scapolites are suggested to be of regional metamorphic origin. The formation of wollastonite, other conditions remaining same, is shown to have been favoured by higher CaO/(FeO+MgO) ratio of these rocks.