Lanping basin was a massif (land massif) in late Palaeozoic Era. The ocean of Jinshajiang separated it from Yangtze plate in east. Lancangjiang ocean separated it from Yunnan—Tibet plate in west. From late Permian Ep...Lanping basin was a massif (land massif) in late Palaeozoic Era. The ocean of Jinshajiang separated it from Yangtze plate in east. Lancangjiang ocean separated it from Yunnan—Tibet plate in west. From late Permian Epoch, the oceanic crust of Jinshajiang subduced the west from east, the one of Lancangjiang down went the east from west, and then the Yunnan—Tibet ancient land gradually closed to the Yangtze. In the end of the Permian Period, two continents and Lanping plate touched together, and the evolution history of the Paleotethys was end. Hercynian orogenic belt in the east and west sides of Lanping had volcanic rock colliding in early—middle Triassic Epoch. In Ladinian in middle Triassic and Carnian in late Triassic, the north side of Lanping basin formed the serial volcanic rock of spilite—quartz keratophyre because mantle\|derived magma causing by delamination rose and mixed with the constituent of continental crust. The volcanic rock overlapped the middle Triassic and late Palaeozoic stratum in angular unconformity. It was the feature of double peak or evolution from the basic to the acid. The race element distribution of volcanic rock was same as the one of tholeiite in island and inter\|arc basin. The rate of lead isotope of the volcanic rock was much higher. These points all distributed above the NHRL in Pb\|Pb. This indicated that the Pb of volcanic rock was the mantle\|derived magma mixed with crust one. The large\|area progression in Lanping rift basin begun in late Carnian.. The east side in Lanping basin developed the sedimentary system that was granule gravel (grit) rock in border facies—limestone in beach facies—black shale, and the middle had black shale, banded siliceous rock, brecciform limestone in late Carnian to Norian. The geochemistry research of siliceous rock showed that the genesis of the chert was hot water. The development of brecciform limestone was related with action of central\|axis rift. The Lanping rift basin went into consuming stage in Rhaetian Epoch of the late Triassic. The basin developed clastic rock bearing coal of continental\|oceanic alternation facies. In early Jurassic, the sedimentary area atrophied further, and the fine lacustrine sediment whose thickness was not great developed in the east of central\|axis. The west stratum of the basin in late Triassic Epoch touched directly with the one in middle Jurassic. Lanping basin was going into another evolution stage that was down\|warped basin.展开更多
Central Fujian Rift is another new and important volcanogenic massive sulfide Pb-Zn polymetallic metallogenetic belt. In order to find out the material genesis and mineralization period of Meixian-type Pb-Zn-Ag deposi...Central Fujian Rift is another new and important volcanogenic massive sulfide Pb-Zn polymetallic metallogenetic belt. In order to find out the material genesis and mineralization period of Meixian-type Pb-Zn-Ag deposits, S and Pb isotope analysis and isotope geochronology of ores and wall rocks for five major deposits are discussed. It is concluded that the composition of sulfur isotope from sulfide ore vary slightly in different deposits and the mean value is close to zero with the 834S ranging from -3.5‰ to ＋5.6‰ averaging at ＋2.0‰, which indicates that the sulfur might originate from magma or possibly erupted directly from volcano or was leached from ore-hosted volcanic rock. The lead from ores in most deposits displays radioactive genesis character （206pb/204pb〉18.140, 207Pb/204pb〉15.584, 208pb/204pb〉38.569） and lead isotope values of ores are higher than those of wall rocks, which indicates that the lead was likely leached from the ore-hosted volcanic rocks. Based on isotope data, two significant Pb-Zn metallogenesis are delineated, which are Mid- and Late-Proterozoic sedimentary exhalative metailogenesis （The single zircon U-Pb, Sm-Nd isochronal and Ar-Ar dating ages of ore- hosted wall rocks are calculated to be among 933-1788 Ma.） and Yanshanian magmatic hydrothermal superimposed and alternated metallogenesis （intrusive SHRIMP zircon U-Pb and Rb-Sr isochronal ages between 127-154 Ma）.展开更多
The discovery of the giant Anyue gas field in Sichuan Basin gives petroleum explorers confidence to find oil and gas in Proterozoic to Cambrian.Based on the reconstruction of tectonic setting and the analysis of major...The discovery of the giant Anyue gas field in Sichuan Basin gives petroleum explorers confidence to find oil and gas in Proterozoic to Cambrian.Based on the reconstruction of tectonic setting and the analysis of major geological events in Mesoproterozoic-Neoproterozoic,the petroleum geological conditions of Proterozoic to Cambrian are discussed in this paper from three aspects,i.e.source rocks,reservoir conditions,and the type and efficiency of play.It is found that lower organisms boomed in the interglacial epoch from Mesoproterozoic-Neoproterozoic to Eopaleozoic when the organic matters concentrated and high quality source rocks formed.Sinian-Cambrian microbial rock and grain-stone banks overlapped with multiple-period constructive digenesis may form large-scale reservoir rocks.However,because of the anoxic event and weak weathering effect in Eopaleozoic-Mesoproterozoic,the reservoirs are generally poor in quality,and only the reservoirs that suffered weathering and leaching may have the opportunity to form dissolution-reconstructed reservoirs.There are large rifts formed during Mesoproterozoic-Neoproterozoic in Huabei Craton,Yangtze Craton,and Tarim Craton in China,and definitely source rocks in the rifts,while whether there are favorite source-reservoir plays depends on circumstance.The existence of Sinian-Cambrian effective play has been proved in Upper Yangtze area.The effectiveness of source-reservoir plays in Huabei area depends on two factors:(1)the effectiveness of secondary play formed by Proterozoic source rock and Paleozoic,Mesozoic,Cenozoic reservoir rocks;(2)the matching between reservoirs formed by reconstruction from Mesoproterozoic-Neoproterozoic to Eopaleozoic and the inner hydrocarbon kitchens with late hydrocarbon generation.As for Tarim Basin,the time of Proterozoic and the original basin should be analyzed before the evaluation of the effective play.To sum up,Proterozoic to Cambrian in the three craton basins in China is a potential exploration formation,which deserves further investigation and research.展开更多
文摘Lanping basin was a massif (land massif) in late Palaeozoic Era. The ocean of Jinshajiang separated it from Yangtze plate in east. Lancangjiang ocean separated it from Yunnan—Tibet plate in west. From late Permian Epoch, the oceanic crust of Jinshajiang subduced the west from east, the one of Lancangjiang down went the east from west, and then the Yunnan—Tibet ancient land gradually closed to the Yangtze. In the end of the Permian Period, two continents and Lanping plate touched together, and the evolution history of the Paleotethys was end. Hercynian orogenic belt in the east and west sides of Lanping had volcanic rock colliding in early—middle Triassic Epoch. In Ladinian in middle Triassic and Carnian in late Triassic, the north side of Lanping basin formed the serial volcanic rock of spilite—quartz keratophyre because mantle\|derived magma causing by delamination rose and mixed with the constituent of continental crust. The volcanic rock overlapped the middle Triassic and late Palaeozoic stratum in angular unconformity. It was the feature of double peak or evolution from the basic to the acid. The race element distribution of volcanic rock was same as the one of tholeiite in island and inter\|arc basin. The rate of lead isotope of the volcanic rock was much higher. These points all distributed above the NHRL in Pb\|Pb. This indicated that the Pb of volcanic rock was the mantle\|derived magma mixed with crust one. The large\|area progression in Lanping rift basin begun in late Carnian.. The east side in Lanping basin developed the sedimentary system that was granule gravel (grit) rock in border facies—limestone in beach facies—black shale, and the middle had black shale, banded siliceous rock, brecciform limestone in late Carnian to Norian. The geochemistry research of siliceous rock showed that the genesis of the chert was hot water. The development of brecciform limestone was related with action of central\|axis rift. The Lanping rift basin went into consuming stage in Rhaetian Epoch of the late Triassic. The basin developed clastic rock bearing coal of continental\|oceanic alternation facies. In early Jurassic, the sedimentary area atrophied further, and the fine lacustrine sediment whose thickness was not great developed in the east of central\|axis. The west stratum of the basin in late Triassic Epoch touched directly with the one in middle Jurassic. Lanping basin was going into another evolution stage that was down\|warped basin.
文摘Central Fujian Rift is another new and important volcanogenic massive sulfide Pb-Zn polymetallic metallogenetic belt. In order to find out the material genesis and mineralization period of Meixian-type Pb-Zn-Ag deposits, S and Pb isotope analysis and isotope geochronology of ores and wall rocks for five major deposits are discussed. It is concluded that the composition of sulfur isotope from sulfide ore vary slightly in different deposits and the mean value is close to zero with the 834S ranging from -3.5‰ to ＋5.6‰ averaging at ＋2.0‰, which indicates that the sulfur might originate from magma or possibly erupted directly from volcano or was leached from ore-hosted volcanic rock. The lead from ores in most deposits displays radioactive genesis character （206pb/204pb〉18.140, 207Pb/204pb〉15.584, 208pb/204pb〉38.569） and lead isotope values of ores are higher than those of wall rocks, which indicates that the lead was likely leached from the ore-hosted volcanic rocks. Based on isotope data, two significant Pb-Zn metallogenesis are delineated, which are Mid- and Late-Proterozoic sedimentary exhalative metailogenesis （The single zircon U-Pb, Sm-Nd isochronal and Ar-Ar dating ages of ore- hosted wall rocks are calculated to be among 933-1788 Ma.） and Yanshanian magmatic hydrothermal superimposed and alternated metallogenesis （intrusive SHRIMP zircon U-Pb and Rb-Sr isochronal ages between 127-154 Ma）.
基金Supported by the China National Science and Technology Major Project(2016ZX05004)
文摘The discovery of the giant Anyue gas field in Sichuan Basin gives petroleum explorers confidence to find oil and gas in Proterozoic to Cambrian.Based on the reconstruction of tectonic setting and the analysis of major geological events in Mesoproterozoic-Neoproterozoic,the petroleum geological conditions of Proterozoic to Cambrian are discussed in this paper from three aspects,i.e.source rocks,reservoir conditions,and the type and efficiency of play.It is found that lower organisms boomed in the interglacial epoch from Mesoproterozoic-Neoproterozoic to Eopaleozoic when the organic matters concentrated and high quality source rocks formed.Sinian-Cambrian microbial rock and grain-stone banks overlapped with multiple-period constructive digenesis may form large-scale reservoir rocks.However,because of the anoxic event and weak weathering effect in Eopaleozoic-Mesoproterozoic,the reservoirs are generally poor in quality,and only the reservoirs that suffered weathering and leaching may have the opportunity to form dissolution-reconstructed reservoirs.There are large rifts formed during Mesoproterozoic-Neoproterozoic in Huabei Craton,Yangtze Craton,and Tarim Craton in China,and definitely source rocks in the rifts,while whether there are favorite source-reservoir plays depends on circumstance.The existence of Sinian-Cambrian effective play has been proved in Upper Yangtze area.The effectiveness of source-reservoir plays in Huabei area depends on two factors:(1)the effectiveness of secondary play formed by Proterozoic source rock and Paleozoic,Mesozoic,Cenozoic reservoir rocks;(2)the matching between reservoirs formed by reconstruction from Mesoproterozoic-Neoproterozoic to Eopaleozoic and the inner hydrocarbon kitchens with late hydrocarbon generation.As for Tarim Basin,the time of Proterozoic and the original basin should be analyzed before the evaluation of the effective play.To sum up,Proterozoic to Cambrian in the three craton basins in China is a potential exploration formation,which deserves further investigation and research.
