By examining structures,sediments,reservoirs and accumulation assemblages in the Deyang-Anyue rift and its surrounding area,four new understandings are obtained.First,during the initiation period of Deyang-Anyue rift,...By examining structures,sediments,reservoirs and accumulation assemblages in the Deyang-Anyue rift and its surrounding area,four new understandings are obtained.First,during the initiation period of Deyang-Anyue rift,multiple groups of faults developed in the rift due to the effect of tensile force,bringing about multiple mound and shoal belts controlled by horsts in the second member of the Sinian Dengying Formation;in the development stage of the rift,the boundary faults of the rift controlled the development of mound and shoal belts at the platform margin in the fourth member of Dengying Formation;during the shrinkage period of the rift,platform margin grain shoals of the Cambrian Canglangpu Formation developed in the rift margin.Second,four sets of large-scale mound and shoal reservoirs in the second member of Dengying Formation,the fourth member of Dengying Formation,Canglangpu Formation and Longwangmiao Formation overlap with several sets of source rocks such as Qiongzhusi Formation source rocks and Dengying Formation argillaceous limestone or dolomite developed inside and outside the rift,forming good source-reservoir-cap rock combinations;the sealing of tight rock layers in the lateral and updip direction results in the formation model of large lithologic gas reservoirs of oil pool before gas,continuous charging and independent preservation of each gas reservoir.Third,six favorable exploration zones of large-scale lithologic gas reservoirs have been sorted out through comprehensive evaluation,namely,mound and shoal complex controlled by horsts in the northern part of the rift in the second member of Dengying Formation,isolated karst mound and shoal complex of the fourth member of Dengying Formation in the south of the rift,the superimposed area of multi-stage platform margin mounds and shoals of the second and fourth members of Dengying Formation and Canglangpu Formation in the north slope area,the platform margin mounds and shoals of the second and fourth members of Dengying Formation in the west side of the rift,the platform margin mound and shoal bodies of the fourth member of Dengying Formation in the south slope area,etc.Fourth,Well Pengtan-1 drilled on the mound and shoal complex controlled by horsts of the second member of Dengying Formation in the rift and Well Jiaotan-1 drilled on the platform margin mound and shoal complex of the North Slope have obtained high-yield gas flows in multiple target layers,marking the discovery of a new gas province with reserves of(2-3)×10^(12) m^(3).This has proved the huge exploration potential of large lithologic gas reservoir group related to intracratonic rift.展开更多
There are abundant and highly varied trace fossils in the Sinian-Cambrian boundary beds in eastern Yunnan. Collections from 27 sections and their study give altogether 45 ichnogenera and 87 ichnospecies. Among them, 2...There are abundant and highly varied trace fossils in the Sinian-Cambrian boundary beds in eastern Yunnan. Collections from 27 sections and their study give altogether 45 ichnogenera and 87 ichnospecies. Among them, 2 ichnogenera and 7 ichnospecies are new, and 31 known ichnogenera and 38 known ichnospecies first found in the region. According to their order of appearance in the boundary beds and their assemblage features, the trace fossils in the Sinian-Cambrian boundary beds in the region may fall into 4 trace fossil assemblage zones in ascending order. In the paper they are correlated with those in the equivalent horizons abroad and their geological significance is discussed preliminarily.展开更多
This paper reports the geochemical and zircon U-Pb dating data of the Sinian to Cambrian low-grade metamorphic rocks in the Miaoer Mountain area,Guangxi and the Jinjiling area,Hunan Province.Petrographic and geochemic...This paper reports the geochemical and zircon U-Pb dating data of the Sinian to Cambrian low-grade metamorphic rocks in the Miaoer Mountain area,Guangxi and the Jinjiling area,Hunan Province.Petrographic and geochemical features indicate that protoliths of these metamorphic rocks are clastic sedimentary rocks with medium weathering,which were formed in the passive continental margin.Geochemistry and zircon U-Pb ages indicate that the Sinian and Cambrian sedimentary rocks in the Jinjiling area have similar detritus components,which are characterized by abundant Grenvillian detrital zircons,suggesting a close affinity with the Cathaysia Block.The Cambrian sedimentary rocks in the Miaoer Mountain area have similar geochemistry and zircon geochronology to those in the Jinjiling area,showing an affinity with the Cathaysia Block.However,the Sinian sedimentary rocks in the Miaoer Mountain area show different geochemical features from the Cambrian sedimentary rocks and those in the Jinjiling area,and are characterized by abundant 840–700 Ma detrital zircons and less^2.0 Ga ones,showing a close affinity with the Yangtze Block.These variations suggest that the Jinjiling area continuously accepted the fragments from the Cathaysia from the Sinian to the Cambrian,whereas the provenance of the Miaoer Mountain sedimentary basin changed from the Yangtze Block to the Cathaysia Block during this interval.This change implies a tectonic movement,which caused the further sinking of the basin in the Miaoer Mountain area and northwestward transferring of the basin center before the Middle Cambrian,so that the Miaoer Mountain basin received the detritus from the Cathaysia Block in the Middle Cambrian.This fact also proves that the Yangtze and Cathaysia blocks have converged at least in Middle Cambrian,and the southwestern boundary between them is located between the Miaoer Mountain and Jinjiling areas.展开更多
基金Supported by the National Science and Technology Major Project(2016ZX05007-002)。
文摘By examining structures,sediments,reservoirs and accumulation assemblages in the Deyang-Anyue rift and its surrounding area,four new understandings are obtained.First,during the initiation period of Deyang-Anyue rift,multiple groups of faults developed in the rift due to the effect of tensile force,bringing about multiple mound and shoal belts controlled by horsts in the second member of the Sinian Dengying Formation;in the development stage of the rift,the boundary faults of the rift controlled the development of mound and shoal belts at the platform margin in the fourth member of Dengying Formation;during the shrinkage period of the rift,platform margin grain shoals of the Cambrian Canglangpu Formation developed in the rift margin.Second,four sets of large-scale mound and shoal reservoirs in the second member of Dengying Formation,the fourth member of Dengying Formation,Canglangpu Formation and Longwangmiao Formation overlap with several sets of source rocks such as Qiongzhusi Formation source rocks and Dengying Formation argillaceous limestone or dolomite developed inside and outside the rift,forming good source-reservoir-cap rock combinations;the sealing of tight rock layers in the lateral and updip direction results in the formation model of large lithologic gas reservoirs of oil pool before gas,continuous charging and independent preservation of each gas reservoir.Third,six favorable exploration zones of large-scale lithologic gas reservoirs have been sorted out through comprehensive evaluation,namely,mound and shoal complex controlled by horsts in the northern part of the rift in the second member of Dengying Formation,isolated karst mound and shoal complex of the fourth member of Dengying Formation in the south of the rift,the superimposed area of multi-stage platform margin mounds and shoals of the second and fourth members of Dengying Formation and Canglangpu Formation in the north slope area,the platform margin mounds and shoals of the second and fourth members of Dengying Formation in the west side of the rift,the platform margin mound and shoal bodies of the fourth member of Dengying Formation in the south slope area,etc.Fourth,Well Pengtan-1 drilled on the mound and shoal complex controlled by horsts of the second member of Dengying Formation in the rift and Well Jiaotan-1 drilled on the platform margin mound and shoal complex of the North Slope have obtained high-yield gas flows in multiple target layers,marking the discovery of a new gas province with reserves of(2-3)×10^(12) m^(3).This has proved the huge exploration potential of large lithologic gas reservoir group related to intracratonic rift.
基金This research was a project (No. 4870087) supported by the National Natural Science Foundation of China.
文摘There are abundant and highly varied trace fossils in the Sinian-Cambrian boundary beds in eastern Yunnan. Collections from 27 sections and their study give altogether 45 ichnogenera and 87 ichnospecies. Among them, 2 ichnogenera and 7 ichnospecies are new, and 31 known ichnogenera and 38 known ichnospecies first found in the region. According to their order of appearance in the boundary beds and their assemblage features, the trace fossils in the Sinian-Cambrian boundary beds in the region may fall into 4 trace fossil assemblage zones in ascending order. In the paper they are correlated with those in the equivalent horizons abroad and their geological significance is discussed preliminarily.
基金supported by the National Natural Science Foundation of China(Grant No.41272085)research grants from the Bureau of Nuclear Geology of China(YK11)+1 种基金the Major State Basic Research Program(Grant No.2012CB416701)the State Key Laboratory for Mineral Deposits Research(Nanjing University)(Grant No.ZZKT-201106)
文摘This paper reports the geochemical and zircon U-Pb dating data of the Sinian to Cambrian low-grade metamorphic rocks in the Miaoer Mountain area,Guangxi and the Jinjiling area,Hunan Province.Petrographic and geochemical features indicate that protoliths of these metamorphic rocks are clastic sedimentary rocks with medium weathering,which were formed in the passive continental margin.Geochemistry and zircon U-Pb ages indicate that the Sinian and Cambrian sedimentary rocks in the Jinjiling area have similar detritus components,which are characterized by abundant Grenvillian detrital zircons,suggesting a close affinity with the Cathaysia Block.The Cambrian sedimentary rocks in the Miaoer Mountain area have similar geochemistry and zircon geochronology to those in the Jinjiling area,showing an affinity with the Cathaysia Block.However,the Sinian sedimentary rocks in the Miaoer Mountain area show different geochemical features from the Cambrian sedimentary rocks and those in the Jinjiling area,and are characterized by abundant 840–700 Ma detrital zircons and less^2.0 Ga ones,showing a close affinity with the Yangtze Block.These variations suggest that the Jinjiling area continuously accepted the fragments from the Cathaysia from the Sinian to the Cambrian,whereas the provenance of the Miaoer Mountain sedimentary basin changed from the Yangtze Block to the Cathaysia Block during this interval.This change implies a tectonic movement,which caused the further sinking of the basin in the Miaoer Mountain area and northwestward transferring of the basin center before the Middle Cambrian,so that the Miaoer Mountain basin received the detritus from the Cathaysia Block in the Middle Cambrian.This fact also proves that the Yangtze and Cathaysia blocks have converged at least in Middle Cambrian,and the southwestern boundary between them is located between the Miaoer Mountain and Jinjiling areas.
