The Early-Middle Devonian Shugouzi Formation in the Quruqtagh block consists mainly of clastic rocks.However,their provenance has been scarcely studied since it was named.Geochemistry of clastic rocks was commonly use...The Early-Middle Devonian Shugouzi Formation in the Quruqtagh block consists mainly of clastic rocks.However,their provenance has been scarcely studied since it was named.Geochemistry of clastic rocks was commonly used to interpret the provenance.Detrital heavy mineral analyses help frame the U-Pb age from zircon grains,integrated with geochemical data from detrital tourmaline and spinels.These techniques were used to characterize components of the sediment flux and define erosion areas in the Qurugtagh block,further providing evidence about the tectonic evolution of the South Tianshan and Tarim plate.The maximum depositional age constrained by detrital zircon dating was Early-Middle Devonian.Multiple diagrams for sedimentary provenance using major and trace elements indicate that continental island arc-related felsic rocks were the major source rocks for the Shugouzi Formation.Detrital tourmalines are dravite and schorl.The results of detrital tourmaline electron probe microanalysis(EPMA)show that the source rocks are mainly metasedimentary rocks and granitoids.The detrital chromian spinels within the sediments are characterized by high chroumium(Cr^(#))and varying magnesium(Mg^(#)).The discrimination plots reveal that these spinels were sourced from island arc magmatic rocks.The laser ablation inductively-coupled plasma mass spectrometry(LA-ICP-MS)U-Pb chronology of detrital zircons suggests that the sediments were derived mainly from 414-491 Ma and 744-996 Ma magmatic rocks.Paleocurrent restoration,sandstone geochemistry,EPMA,and detrital zircon geochronology indicate that the source rocks were predominantly derived from Late Ordovician and Devonian magmatic rocks and subordinately from recycled Neoproterozoic magmatic rocks.Comprehensive analyses of the source areas suggest that a remnant arc still existed in the Early Devonian and the Shugouzi Formation was deposited in a passive continental margin.展开更多
位于特提斯喜马拉雅北亚带的江孜地区古近纪甲查拉组角度不整合于晚白垩世宗卓组之上,系该地区最高(时代最晚)海相地层。运用岩石学和地球化学方法对其进行分析研究结果表明该组物源区主要为近源再旋回造山带,岩屑的母岩类型主要是岩浆...位于特提斯喜马拉雅北亚带的江孜地区古近纪甲查拉组角度不整合于晚白垩世宗卓组之上,系该地区最高(时代最晚)海相地层。运用岩石学和地球化学方法对其进行分析研究结果表明该组物源区主要为近源再旋回造山带,岩屑的母岩类型主要是岩浆弧成因的中性、中酸性安山质火山岩。新生代以前,特提斯喜马拉雅属于印度板块的被动大陆边缘,从特提斯喜马拉雅南亚带向北亚带显示了一种从浅水陆棚到深水盆地的变化,在侏罗-白垩纪时其陆源碎屑物主要是成熟度极高的石英砂岩,所以甲查拉组的碎屑物质只能来源于当时的冈底斯弧地区,所获有限的古水流证据也指示了这一点。从欧亚大陆侵蚀下来的碎屑物质被带到原印度大陆地区沉积,暗示该区的特提斯洋壳已经完全消失,印度与欧亚大陆在特提斯喜马拉雅中、东部产生了初始的陆-陆碰撞,其碰撞的启动时间为甲查拉组开始沉积的65 M a±。展开更多
基金financially supported by Deep Resources Exploration and Mining Project(Grant No.2019YFC0605202)Chinese Geological Survey(Grant No.DD20221684)。
文摘The Early-Middle Devonian Shugouzi Formation in the Quruqtagh block consists mainly of clastic rocks.However,their provenance has been scarcely studied since it was named.Geochemistry of clastic rocks was commonly used to interpret the provenance.Detrital heavy mineral analyses help frame the U-Pb age from zircon grains,integrated with geochemical data from detrital tourmaline and spinels.These techniques were used to characterize components of the sediment flux and define erosion areas in the Qurugtagh block,further providing evidence about the tectonic evolution of the South Tianshan and Tarim plate.The maximum depositional age constrained by detrital zircon dating was Early-Middle Devonian.Multiple diagrams for sedimentary provenance using major and trace elements indicate that continental island arc-related felsic rocks were the major source rocks for the Shugouzi Formation.Detrital tourmalines are dravite and schorl.The results of detrital tourmaline electron probe microanalysis(EPMA)show that the source rocks are mainly metasedimentary rocks and granitoids.The detrital chromian spinels within the sediments are characterized by high chroumium(Cr^(#))and varying magnesium(Mg^(#)).The discrimination plots reveal that these spinels were sourced from island arc magmatic rocks.The laser ablation inductively-coupled plasma mass spectrometry(LA-ICP-MS)U-Pb chronology of detrital zircons suggests that the sediments were derived mainly from 414-491 Ma and 744-996 Ma magmatic rocks.Paleocurrent restoration,sandstone geochemistry,EPMA,and detrital zircon geochronology indicate that the source rocks were predominantly derived from Late Ordovician and Devonian magmatic rocks and subordinately from recycled Neoproterozoic magmatic rocks.Comprehensive analyses of the source areas suggest that a remnant arc still existed in the Early Devonian and the Shugouzi Formation was deposited in a passive continental margin.
文摘位于特提斯喜马拉雅北亚带的江孜地区古近纪甲查拉组角度不整合于晚白垩世宗卓组之上,系该地区最高(时代最晚)海相地层。运用岩石学和地球化学方法对其进行分析研究结果表明该组物源区主要为近源再旋回造山带,岩屑的母岩类型主要是岩浆弧成因的中性、中酸性安山质火山岩。新生代以前,特提斯喜马拉雅属于印度板块的被动大陆边缘,从特提斯喜马拉雅南亚带向北亚带显示了一种从浅水陆棚到深水盆地的变化,在侏罗-白垩纪时其陆源碎屑物主要是成熟度极高的石英砂岩,所以甲查拉组的碎屑物质只能来源于当时的冈底斯弧地区,所获有限的古水流证据也指示了这一点。从欧亚大陆侵蚀下来的碎屑物质被带到原印度大陆地区沉积,暗示该区的特提斯洋壳已经完全消失,印度与欧亚大陆在特提斯喜马拉雅中、东部产生了初始的陆-陆碰撞,其碰撞的启动时间为甲查拉组开始沉积的65 M a±。
