Broad-band and long period magnetotelluric measurements made at 63 locations along -500 km long Chikmagalur-Kavali profile,that cut across the Dharwar craton (DC) and Eastern Ghat Mobile Belt (EGMB) in south India,is ...Broad-band and long period magnetotelluric measurements made at 63 locations along -500 km long Chikmagalur-Kavali profile,that cut across the Dharwar craton (DC) and Eastern Ghat Mobile Belt (EGMB) in south India,is modelled to examine the lithosphere architecture of the cratonic domain and define tectonic boundaries.The 2-D resistivity model shows moderately conductive features that intersperse a highly resistive background of crystalline rocks and spatially connect to the exposed schist belts or granitic intrusions in the DC.These features are therefore interpreted as images of fossil pathways of the volcanic emplacements associated with the greenstone belt and granite suite formation exposed in the region.A near vertical conductive feature in the upper mantle under the Chitradurga Shear Zone represents the Archean suture between the western and eastern blocks of DC.Although thick (-200 km) cratonic (highly resistive) lithosphere is preserved,significant part of the cratonic lithosphere below the western DC is modified due to plume-continental lithosphere interactions during the CretaceouseTertiary period.A west-verging moderately conductive feature imaged beneath EGMB lithosphere is interpreted as the remnant of the Proterozoic collision process between the Indian land mass and East Antarctica.Thin (-120 km) lithosphere is seen below the EGMB,which form the exterior margin of the India shield subsequent to its separation from East Antarctica through rifting and opening of the Indian Ocean in the Cretaceous.展开更多
The polycarbosilane(PCS)precursor for SiC with high molecular weight and medium molecular weight distribution was synthesized from polydimethylsilane at normal pressure.The chemical formula,the number average molecula...The polycarbosilane(PCS)precursor for SiC with high molecular weight and medium molecular weight distribution was synthesized from polydimethylsilane at normal pressure.The chemical formula,the number average molecular weight,and the polydispersivity index of the synthesized PCS are SiC_(1.94)H_(5.01)O_(0.028),1135,and 1.66,respectively,which can be attributed to the higher reaction temperature used for polymerization.The polymer to ceramic conversion of PCS was completed at 900℃with a ceramic yield of 85%.The crystallization started at 1100℃,and at 1200℃,well resolved peaks ofβ-SiC were formed with small amount ofα-cristobalite.The X-ray diffraction(XRD)and transmission electron microscopy(TEM)studies indicated the presence of nanocrystallineβ-SiC.展开更多
基金under the Supra Institutional Project (SIP-0012)carried under INDEX (PSC0204) project,funded by Council of Scientific and Industrial Research (CSIR), New Delhi, India
文摘Broad-band and long period magnetotelluric measurements made at 63 locations along -500 km long Chikmagalur-Kavali profile,that cut across the Dharwar craton (DC) and Eastern Ghat Mobile Belt (EGMB) in south India,is modelled to examine the lithosphere architecture of the cratonic domain and define tectonic boundaries.The 2-D resistivity model shows moderately conductive features that intersperse a highly resistive background of crystalline rocks and spatially connect to the exposed schist belts or granitic intrusions in the DC.These features are therefore interpreted as images of fossil pathways of the volcanic emplacements associated with the greenstone belt and granite suite formation exposed in the region.A near vertical conductive feature in the upper mantle under the Chitradurga Shear Zone represents the Archean suture between the western and eastern blocks of DC.Although thick (-200 km) cratonic (highly resistive) lithosphere is preserved,significant part of the cratonic lithosphere below the western DC is modified due to plume-continental lithosphere interactions during the CretaceouseTertiary period.A west-verging moderately conductive feature imaged beneath EGMB lithosphere is interpreted as the remnant of the Proterozoic collision process between the Indian land mass and East Antarctica.Thin (-120 km) lithosphere is seen below the EGMB,which form the exterior margin of the India shield subsequent to its separation from East Antarctica through rifting and opening of the Indian Ocean in the Cretaceous.
文摘The polycarbosilane(PCS)precursor for SiC with high molecular weight and medium molecular weight distribution was synthesized from polydimethylsilane at normal pressure.The chemical formula,the number average molecular weight,and the polydispersivity index of the synthesized PCS are SiC_(1.94)H_(5.01)O_(0.028),1135,and 1.66,respectively,which can be attributed to the higher reaction temperature used for polymerization.The polymer to ceramic conversion of PCS was completed at 900℃with a ceramic yield of 85%.The crystallization started at 1100℃,and at 1200℃,well resolved peaks ofβ-SiC were formed with small amount ofα-cristobalite.The X-ray diffraction(XRD)and transmission electron microscopy(TEM)studies indicated the presence of nanocrystallineβ-SiC.
