The study area is located in the south of Huanxian county,in Yan'an and Puxian counties and to the north of Xi'an.The Shanxi and lower Shihezi formations are important gas-bearing formations.Given our analysis...The study area is located in the south of Huanxian county,in Yan'an and Puxian counties and to the north of Xi'an.The Shanxi and lower Shihezi formations are important gas-bearing formations.Given our analysis of the direction of rivers,the contents of stable heavy minerals and of feldspar of palaeo river systems,the study area is divided into six palaeodrainage patterns corresponding to six feldspar regions and six sedimentary facies regions.On this basis,the distribution of sedimentary facies was also analyzed.During the Shanxi stage,a delta front was deposited in the Huanxian region and delta plains and fronts were deposited in the Pingliang,Chunhua-Yaoxian and Hancheng-Chengcheng regions.In the Yan'an-Daning region,only a delta front was developed.The distribution of sedimentary facies in the earlier Shihezi stage originated from the Shanxi stage.A delta front was developed in the Huanxian region while a delta plain and front developed in the Pingliang-Zhenyuan region during the same time.Lakes originated only in the Zhenyuan-Huanxian-Huachi-Zhengning and Daning-Jixian zones.This analytical method shows that different palaeodrainage patterns can be effectively distinguished in order to forecast sedimentary facies.展开更多
Mantle plume upwelling and associated topographic doming may affect sedimentation systems over large areas of the Earth's crust,including drainage basins.An integrated provenance study,including petrography,palaeo...Mantle plume upwelling and associated topographic doming may affect sedimentation systems over large areas of the Earth's crust,including drainage basins.An integrated provenance study,including petrography,palaeocurrent data,heavy mineral chemistry,and detrital monazite dating of the Palaeo-Mesozoic Gondwana sandstones in the Mahanadi Basin in eastern India,tracks sediment sources,reconstructs the palaeogeography of eastern Gondwanaland,and records the effects of doming on drainage pattern.The sandstones are mostly arkosic to quartz arenite,sourced from transitional continental to craton interior regions.Garnet chemistry from Permian sandstones suggests a dominant contribution from source rocks metamorphosed under amphibolite to granulite facies conditions.Tourmaline chemistry of the Late Carboniferous to the Late Triassic sandstones links its source primarily to metapelites and metapsammites rocks,while the same indicates predominant Li-poor granitoid sources for the Early Cretaceous sandstones.The spectrum of monazite detrital ages of the Mahanadi sandstones reveals four major clusters:(1)2385-2249 Ma,(2)1627-1547 Ma,(3)1146-662 Ma,and(4)571-410 Ma.The integration of heavy mineral chemistry,petrography,monazite geochronology,and palaeocurrent data,from the Permo-Carboniferous to the Late Triassic sandstones,establishes sediment sources within the Eastern Ghats Mobile Belt and the Singhbhum Mobile Belt of India,and East Antarctica.In contrast,the southerly palaeocurrent record of the Early Cretaceous deposit indicates sediment supply from the Rengali province of the Eastern Ghats Mobile Belt(EGMB)and the Chhotanagpur Gneissic Complex.Therefore,Early Cretaceous sandstones attest to a change in source rock,primarily controlled by the south-easterly tilting of the basin,linked to the mantle plume-related domal uplift.This study also highlights that before the breakup of Gondwanaland,East Antarctica and EGMB existed as a single landmass.展开更多
基金Projects OF06142 supported by the National Basic Research Program of China2001CB209100 by the Science Foundation of China University of Mining and Technology
文摘The study area is located in the south of Huanxian county,in Yan'an and Puxian counties and to the north of Xi'an.The Shanxi and lower Shihezi formations are important gas-bearing formations.Given our analysis of the direction of rivers,the contents of stable heavy minerals and of feldspar of palaeo river systems,the study area is divided into six palaeodrainage patterns corresponding to six feldspar regions and six sedimentary facies regions.On this basis,the distribution of sedimentary facies was also analyzed.During the Shanxi stage,a delta front was deposited in the Huanxian region and delta plains and fronts were deposited in the Pingliang,Chunhua-Yaoxian and Hancheng-Chengcheng regions.In the Yan'an-Daning region,only a delta front was developed.The distribution of sedimentary facies in the earlier Shihezi stage originated from the Shanxi stage.A delta front was developed in the Huanxian region while a delta plain and front developed in the Pingliang-Zhenyuan region during the same time.Lakes originated only in the Zhenyuan-Huanxian-Huachi-Zhengning and Daning-Jixian zones.This analytical method shows that different palaeodrainage patterns can be effectively distinguished in order to forecast sedimentary facies.
基金financial support from UGC,Government of India,New DelhiIIT Bombay for the financial support through the project RI/0220-10001613-001the Department of Science and Technology,Government of India,for the FEG-SEM facility at the Department of Earth Sciences,IIT Bombay,through the FIST grant no.SR/FST/ES-II/2019/63
文摘Mantle plume upwelling and associated topographic doming may affect sedimentation systems over large areas of the Earth's crust,including drainage basins.An integrated provenance study,including petrography,palaeocurrent data,heavy mineral chemistry,and detrital monazite dating of the Palaeo-Mesozoic Gondwana sandstones in the Mahanadi Basin in eastern India,tracks sediment sources,reconstructs the palaeogeography of eastern Gondwanaland,and records the effects of doming on drainage pattern.The sandstones are mostly arkosic to quartz arenite,sourced from transitional continental to craton interior regions.Garnet chemistry from Permian sandstones suggests a dominant contribution from source rocks metamorphosed under amphibolite to granulite facies conditions.Tourmaline chemistry of the Late Carboniferous to the Late Triassic sandstones links its source primarily to metapelites and metapsammites rocks,while the same indicates predominant Li-poor granitoid sources for the Early Cretaceous sandstones.The spectrum of monazite detrital ages of the Mahanadi sandstones reveals four major clusters:(1)2385-2249 Ma,(2)1627-1547 Ma,(3)1146-662 Ma,and(4)571-410 Ma.The integration of heavy mineral chemistry,petrography,monazite geochronology,and palaeocurrent data,from the Permo-Carboniferous to the Late Triassic sandstones,establishes sediment sources within the Eastern Ghats Mobile Belt and the Singhbhum Mobile Belt of India,and East Antarctica.In contrast,the southerly palaeocurrent record of the Early Cretaceous deposit indicates sediment supply from the Rengali province of the Eastern Ghats Mobile Belt(EGMB)and the Chhotanagpur Gneissic Complex.Therefore,Early Cretaceous sandstones attest to a change in source rock,primarily controlled by the south-easterly tilting of the basin,linked to the mantle plume-related domal uplift.This study also highlights that before the breakup of Gondwanaland,East Antarctica and EGMB existed as a single landmass.
