Geochemical constraints on the tectonic setting of the Sonakhan Greenstone Belt, Bastar Craton, Central India  

作　　者：S.D.Deshmukh K.R.Hari P.Diwan M.P.Manu Prasanth 

机构地区：[1]Department of Geology, Govt. V. Y. T. P G Autonomous College [2]School of Studies in Geology and W.R.M., Pt. Ravishankar Shukla University [3]Department of Applied Geology, National Institute of Technology,Raipur, India

出　　处：《Acta Geochimica》2018年第3期489-499,共11页地球化学学报（英文）

基　　金：Financial support from UGC to S.D.Deshmukh

摘　　要：The Neo-Archean Sonakhan Greenstone Belt(SGB) located in the north-eastern fringes of Bastar craton,Central India, is dominated by Basalts, Andesites, Dacites and Rhyolites association. Partial melting modeling on the SGB metabasalts indicates that these rocks were derived by20% melting of spinel peridotite. Fractional crystallisation modeling with REE reveal that the most evolved samples represent the product of fractional crystallization of least evolved magma with 35% plagioclase, 35% clinopyroxene,20% olivine, 5% magnetite and 5% ilmenite as fractionating minerals with 40% remaining magma. Depletion of HFSE with reference to the LILE and LREE/HFSE ratios and Nb, Zr anomalies in the multi-element diagram of the mafic rocks of SGB indicate Island arc magmatic setting.The enriched Th/Yb values further substantiate that the mantle arrays were modified by subduction-related fluids or melts. The general conclusions drawn indicate that the metabasalts from the SGB were formed as a result of subduction of an intraoceanic lithosphere in a fore-arc suprasubduction zone environment.The Neo-Archean Sonakhan Greenstone Belt(SGB) located in the north-eastern fringes of Bastar craton,Central India, is dominated by Basalts, Andesites, Dacites and Rhyolites association. Partial melting modeling on the SGB metabasalts indicates that these rocks were derived by20% melting of spinel peridotite. Fractional crystallisation modeling with REE reveal that the most evolved samples represent the product of fractional crystallization of least evolved magma with 35% plagioclase, 35% clinopyroxene,20% olivine, 5% magnetite and 5% ilmenite as fractionating minerals with 40% remaining magma. Depletion of HFSE with reference to the LILE and LREE/HFSE ratios and Nb, Zr anomalies in the multi-element diagram of the mafic rocks of SGB indicate Island arc magmatic setting.The enriched Th/Yb values further substantiate that the mantle arrays were modified by subduction-related fluids or melts. The general conclusions drawn indicate that the metabasalts from the SGB were formed as a result of subduction of an intraoceanic lithosphere in a fore-arc suprasubduction zone environment.

关 键 词：Supra-subduction Neo-Archean SonakhanGreenstone TERRAIN Bastar CRATON 

分 类 号：P596[天文地球—地球化学]