【摘 要】
：
Cratonic stabilization was a critical crustal process during the Hadean to Archean for the formation of cra-tons.The understanding of how and where this process took place is significant to evaluate the architec-ture of continents.The Singhbhum Craton of
【机 构】
：
CSIR (Council of Scientific and Industrial Research)-National Geophysical Research Institute (NGRI),
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Cratonic stabilization was a critical crustal process during the Hadean to Archean for the formation of cra-tons.The understanding of how and where this process took place is significant to evaluate the architec-ture of continents.The Singhbhum Craton of eastern India has well preserved Precambrian volcano-sedimentary sequences.The Simlipal volcano-sedimentary complex of Singhbhum Craton consists of cir-cular bands of mafic volcanic rocks interlayered with quartzites/ shales/phyllites.In the present study,we report petrographic and geochemical characteristics of quartzites from Simlipal Complex coupled with U-Pb ages of detrital zircons and zircon geochemistry to understand the provenance and depositional conditions and its connection with the crustal stabilization in the Singhbhum Craton.The quartzites are texturally mature with sub-angular to sub-rounded quartz grains followed by feldspars embedded in a silty matrix.Based on modal compositions and major element ratios,these quartzites are categorized as quartz arenite and sub-lithic arenites.Trace element abundances normalized to Archean Upper Continental Crust (AUCC) display positive anomalies at U,Zr,Hf and negative anomalies at Nb.REE pat-terns are characterized by negative Eu anomalies (Eu/Eu* =0.47-0.97) and flat HREE suggesting felsic provenance.These quartzites show depletion of LILE,enrichment of HFSE and transition metals relative to AUCC.High weathering indices such as CIA,PIA,and ICV are suggestive of moderate to intense chem-ical weathering.Low trace element ratios such as Th/Cr,Th/Sc,La/Sc,La/Co and Th/Co indicate a predom-inantly felsic source for these rocks.The overall geochemical signatures indicate passive margin deposition for these quartzites.Detrital zircons from the Simlipal quartzites yield U-Pb ages 3156 ± 31 Ma suggesting Mesoarchean crustal heritage.The trace element geochemistry of detrital zir-cons suggests that the zircons are magmatic in origin and possibly derived from the 3.1 Ga anorogenic granite/granitoid provenance of Singhbhum Craton.These observations collectively indicate the Mayurbhanj Granite and Singhbhum Granite (SBG-Ⅲ) provenance for these quartzites,thereby tracking the stabilization of the eastern Indian Shield/Singhbhum Craton back to Mesoarchean.
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