New Data on the Mineralogy of Chromite from the Nuggihalli Schist Belt,Western Dharwar Craton,Karnataka,India:Petrogenetic Implications

作     者：Perumala V.S.RAJU Elapavalooru V.S.S.K.BABU Roland K.W.MERKLE 

作者机构：National Geophysical Research Institute HyderabadIndia(Council of Scientific and Industrial Research) Department of Geology University of PretoriaPretoriaSouth Africa 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2011年第85卷第1期

页      面：107-115页

核心收录：

学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：project by PVSR(no.GAP 538-28[PVSR]) funded by the Department of Science and Technology Government of India 

主　　题：chromite ferritchromite Nuggihalli schist belt Dharwar Craton India 

摘      要：The occurrence of rhythmic layering of chromite and host serpentinites in the deformed layered igneous complexes has been noticed in the Nuggihalli schist belt （NSB） in the western Dharwar craton, Karnataka, South India. For this study, the chromitite rock samples were collected from Jambur, Tagadur, Bhakatarhalli, Ranganbetta and Byrapur in the NSB. Petrography and ore microscopic studies on chromite show intense cataclasis and alteration to ferritchromite. The ferritchromite compositions are characterized by higher Cr number （Cr/[Cr＋AI]） （0.68-0.98） and lower Mg number （Mg/[Mg＋Fe]） （0.33-0.82） ratios in ferritchromite compared to that of parent chromite. The formation process for the ferritchromite is thought to be related to the exchange of Mg, AI, Cr, and Fe between the chromite, surrounding silicates （serpentines, chlorites）, and fluid during serpentinization.