To predict the large-scale source rock and reservoir distribution in Cambrian subsalt formations(Upper Sinian to Mid-Cambrian)in the Tarim Basin,more than 502D seismic lines and 3D data volume acquired latest,22 wells...To predict the large-scale source rock and reservoir distribution in Cambrian subsalt formations(Upper Sinian to Mid-Cambrian)in the Tarim Basin,more than 502D seismic lines and 3D data volume acquired latest,22 wells and some out-crops around this area were used to study the tectonic-lithofacies paleogeography,define the distribution of large scale source rocks and reservoirs,and sort out favorable zones.(1)The basin experienced evolution from ramp to deep-water mud-rich ramp,low-gradient slope,weak rimmed to strong rimmed platform,and the differentiation in the platform was controlled by pre-Cambrian palaeo-rifts.(2)The Luonan-Yubei ancient rift controlled the distribution of source rocks in the Lower Cambrian Yuertusi Formation,and this rift together with the northern depression are the main source rock area.(3)There are three sets of large-scale reservoirs,the Upper Sinian Qigebulake Formation,the Lower Cambrian Xiaorbulake Formation and the Wu-songger Formation,and shoal-mounds,early dolomitization and multi-levels of unconformities controlled reservoir develop-ment.(4)Four favorable zones,the north slope of Tazhong,upper slope of Maigaiti area,Keping-Wensu periphery,and south slope of Tabei,were evaluated.Of them,the north slope of Tazhong is most likely to have exploration breakthrough;the south slope of Tabei is the best area for exploring the Upper Sinian large scale weathering crust dolomite;Maigaiti slope and Kep-ing-Wensu periphery area improved in exploration potentials significantly,and are worth prospecting faster.展开更多
Sand-rich tight sandstone reservoirs are potential areas for oil and gas exploration. However, the high ratio of sandstone thickness to that of the strata in the formation poses many challenges and uncertainties to tr...Sand-rich tight sandstone reservoirs are potential areas for oil and gas exploration. However, the high ratio of sandstone thickness to that of the strata in the formation poses many challenges and uncertainties to traditional lithofacies paleogeography mapping. Therefore, the prediction of reservoir sweet spots has remained problematic in the field of petroleum exploration. This study provides new insight into resolving this problem, based on the analyses of depositional characteristics of a typical modern sand-rich formation in a shallow braided river delta of the central Sichuan Basin, China. The varieties of sand-rich strata in the braided river delta environment include primary braided channels,secondary distributary channels and the distribution of sediments is controlled by the successive superposed strata deposited in paleogeomorphic valleys. The primary distributary channels have stronger hydrodynamic forces with higher proportions of coarse sand deposits than the secondary distributary channels. Therefore, lithofacies paleogeography mapping is controlled by the geomorphology, valley locations, and the migration of channels. We reconstructed the paleogeomorphology and valley systems that existed prior to the deposition of the Xujiahe Formation. Following this, rock-electro identification model for coarse skeletal sand bodies was constructed based on coring data. The results suggest that skeletal sand bodies in primary distributary channels occur mainly in the valleys and low-lying areas,whereas secondary distributary channels and fine deposits generally occur in the highland areas. The thickness distribution of skeletal sand bodies and lithofacies paleogeography map indicate a positive correlation in primary distributary channels and reservoir thickness. A significant correlation exists between different sedimentary facies and petrophysical properties. In addition, the degree of reservoir development in different sedimentary facies indicates that the mapping method reliably predicts the distribution of sweet spots. The application and understanding of the mapping method provide a reference for exploring tight sandstone reservoirs on a regional basis.展开更多
The middle Permian Cryptospirifer fauna (brachiopod) has hitherto been found in more than 30 localities in the Yangtze Platform, South China. Examination of data from various localities shows that it occurs stratigr...The middle Permian Cryptospirifer fauna (brachiopod) has hitherto been found in more than 30 localities in the Yangtze Platform, South China. Examination of data from various localities shows that it occurs stratigraphically in three intervals in the range from the upper Kungurian to Wordian. In the Baoshan block in western Yunnan the fauna occurs in the basal part of the Daaozi Formation and is of possibly an early Wordian age. Outside China the Cryptospirifer fauna has been reported from central and northwest Iran and central Turkey, where the fauna may have an age around the Wordian/Capitanian boundary. Rapid global warming since the late Early Permian and possession of other suitable environmental factors such as proper substrate, clastic input and water depth enabled the Gondwana-derived Baoshan Block and related tectono-stratigraphic units in Iran and Turkey to host the Cryptospirifer fauna, a fauna evolved in the Yangtze Platform that is a type area of the Cathaysian province.展开更多
Paleogeography is the merger of lithology,depositional environments,tectonic plate movements,topography,climate patterns and ecosystems(reefs,vegetation)through time(e.g.,Scotese,2014,2016,2017;Blakey,2019).The constr...Paleogeography is the merger of lithology,depositional environments,tectonic plate movements,topography,climate patterns and ecosystems(reefs,vegetation)through time(e.g.,Scotese,2014,2016,2017;Blakey,2019).The construction of paleogeographic maps using tectonic plate reconstructions requires a multi-year community effort that shares databases,standards and computer projection methods.展开更多
Paleogeographic analysis accounts for an essential part of geological research,making important contributions in the reconstruction of depositional environments and tectonic evolution histories(Ingalls et al.,2016;Mer...Paleogeographic analysis accounts for an essential part of geological research,making important contributions in the reconstruction of depositional environments and tectonic evolution histories(Ingalls et al.,2016;Merdith et al.,2017),the prediction of mineral resource distributions in continental sedimentary basins(Sun and Wang,2009),and the investigation of climate patterns and ecosystems(Cox,2016).展开更多
The Triassic petrostratigraphic system and chronologic stratigraphic sketch have been updated and perfected in the Qiangtang area, Qinghai-Tibet Plateau based on the integrated 1:250000 regional geological survey and...The Triassic petrostratigraphic system and chronologic stratigraphic sketch have been updated and perfected in the Qiangtang area, Qinghai-Tibet Plateau based on the integrated 1:250000 regional geological survey and the latest research progeny. The first finished 1:3000000 Triassic tectonic lithofacies paleogeographic maps in the Qiangtang area shows that the Triassic tectonic unit in the Qiangtang area can been divided into three parts from north to south: northern Qiangtang block; Longmucuo-Shuanghu suture zone; and southern Qiangtang block. The early-middle Triassic tectonic paleogeography in the Qiangtang area is divides into three sub- units: northern Qiangtang passive continental marginal basin (NQPB), Longmucuo- Shuanghu residual basin (LSRB) and southern Qiangtang residual basin (SQRB). The NQPB can be subdivided into four paleogeography units: The Tanggula-Zangxiahe shallow and bathyal sea; The Wangquanhe- Yingshuiquan carbonate platform; The Rejuechaka-Jiangaidarina littoral- shallow sea; and Qiangtang central uplift. The above units of The NQPB possess EW trend, geomorphology high in the south and low in the north, the seawater depth northward. The basinal paleo-current direction is unidirectional, and basinal tectonic subsidence center is in accord with the depo-center, located in the Tanggula-Zangxiahe belt, north of the basin. The sedimentation and tectonic evolution of the NQPB are characterized with passive continental marginal basin. The Qiangtang central orogenic denuded area (ancient land) may be as a sedimentary materials source of the NQPB. SQRB can be divided into two units: Duoma carbonate platform and southern Qiangtang neritic-deep sea. The late Triassic tectonic paleogeography in the Qiangtang area is the framework of the "archipelagic-sea" as a whole, and it may be divided into three sub-units: northern Qiangtang back- arc foreland basin(NQFB), Longmucuo-Shuanghu residual basin(LSRB) and southern Qiangtang marginal-sea basin(SQMB). Thereinto, NQFB can be divided into five paleogeography units: the Zangxiahe-Mingjinghu bathyal basin characterized with the flysch; the Tanggula shallow-sea shelf with the fine-clastics; the Juhuashang platform with carbonates; the Tumenggela-Shuanghu coastal- delta with coal-bearing clastics and the Nadigangri- Geladandong arc with volcanics and tuffs. In transverse section, the NQFB fills is wedge-shaped, and the sediments characterized with thicker in north and thinner in south, and with double materials derived from the Ruolagangri orogenic belt in north and the Shuanghu central orogenic belt in south. The late Triassic depocenter of NQFB is located in the middle of the basin, the Yakecuo-Bandaohu-Quemocuo belt, but the subsidence center in the north, the Zangxiahe- Mingjinghu belt, and basinal tectonic subsidence center not concordant with the depo-center. Late Triassic, the SQMB may be divided into three sub-units: Xiaochaka shallow-sea; Riganpeicuo platform~ and South Qiangtang southern bathyal basin. In transverse section, the basement of the SQMB is characterized with low in the northern and southern, but high in the middle; forming wedge shaped sediments with thicker in the north and thinner in the south; the sedimentary materials derived from the Qiangtang central uplift and Nadigangri arcs in north. The late Triassic subsidence centre of the SQMB is located in the northern (Xiaochaka area), but the depocenter in the southern (Qixiancuo Suobucha area). The sedimentation and tectonic evolution of the SQMB are characterized with marginal sea.展开更多
Major advances in computational power,as well as community modelling workflows and an improvement in data availability,has revolutionized Earth sciences over the last decade.Geological data has been synthesized into f...Major advances in computational power,as well as community modelling workflows and an improvement in data availability,has revolutionized Earth sciences over the last decade.Geological data has been synthesized into flexible and open access plate tectonic and paleogeographic reconstructions using the open-source and cross-platform GPlates(www.gplates.org)software since 2008(Muller et al.,2018;Muller et al.,2008).展开更多
There are 9 major coal-accumulating periods during geological history in China,including the Early Carboniferous,Late Carboniferous-Early Permian,Middle Permian,Late Permian,Late Triassic,Early-Middle Jurassic,Early C...There are 9 major coal-accumulating periods during geological history in China,including the Early Carboniferous,Late Carboniferous-Early Permian,Middle Permian,Late Permian,Late Triassic,Early-Middle Jurassic,Early Cretaceous,Paleogene and Neogene.The coal formed in these periods were developed in different coal-accumulating areas(CAA)including the North China,South China,Northwest China,Northeast China,the Qinghai–Tibet area,and China offshore area.In this paper,we investigated depositional environments,sequence stratigraphy,lithofacies paleogeography and coal accumulation pattern of five major coal-accumulating periods including the Late Carboniferous to Middle Permian of the North China CAA,the Late Permian of the South China CAA,the Late Triassic of the South China CAA,the Early-Middle Jurassic of the North and Northwest China CAA,and the Early Cretaceous in the Northeast China CAA.According to distribution of the coal-bearing strata and the regional tectonic outlines,we have identified distribution range of the coal-forming basins,sedimentary facies types and coal-accumulating models.The sequence stratigraphic frameworks of the major coal-accumulating periods were established based on recognition of a variety of sequence boundaries.The distribution of thick coals and migration patterns of the coal-accumulating centers in the sequence stratigraphic framework were analyzed.The lithofacies paleogeography maps based on third-order sequences were reconstructed and the distribution of coal accumulation centers and coal-rich belts were predicted.展开更多
The Central-east Asian continent,in which China is presently located,is a composite terrane composed of many small or micro-scale blocks and orogenic belts (Ren et al.,1999).Compared with large-scale cratons such as N...The Central-east Asian continent,in which China is presently located,is a composite terrane composed of many small or micro-scale blocks and orogenic belts (Ren et al.,1999).Compared with large-scale cratons such as North America and Siberia,the blocks that make up China are much smaller.For example,the North China and Siberian blocks,as well as some part of the ancient African continent,belonged to part of the Colombia supercontinent and connected with Baltica (Rogers and Santosh,2002;Lu et al.,2002).After major rifting episodes at 1.8-1.6 Ga.展开更多
A new species of the probable calcareous alga Amsassia, A. koreanensis, is recognized from the Duwibong Formation (Middle Ordovician, Darriwilian) of the Taebaeksan Basin in mid-eastern Korea. This is the first repo...A new species of the probable calcareous alga Amsassia, A. koreanensis, is recognized from the Duwibong Formation (Middle Ordovician, Darriwilian) of the Taebaeksan Basin in mid-eastern Korea. This is the first report of the genus from the Korean Peninsula, expanding its geographical range to the eastern Sino-Korean Block. The new species also occurs in the Xiazhen Formation (Upper Ordovician, Katian) at Zhuzhai in the South China Block. Amsassia koreanensis is the smallest species of this modular genus, having a maximum module diameter of 0.28 ram. Module increase is by bipartite, tripartite and quadripartite types of longitudinal axial fission, but unlike other species of the genus, quadripartite fission is common. The types of fission are comparable to those in some Tetradiida (now Prismostylales, florideophycean rhodophyte algae), although the processes of fission are different. The distribution of A. koreanensis further strengthens the biogeographical connection between the Sino-Korean and South China blocks, suggesting that these two paleocontinents were located closer together during the Middle to Late Ordovician than previously speculated.展开更多
The Bayanhot Basin is a superimposed basin that experienced multiple-staged tectonic movements;it is in the eastern Alxa Block,adjacent to the North China Craton(NCC)and the North Qilian Orogenic Belt(NQOB).There are ...The Bayanhot Basin is a superimposed basin that experienced multiple-staged tectonic movements;it is in the eastern Alxa Block,adjacent to the North China Craton(NCC)and the North Qilian Orogenic Belt(NQOB).There are well-developed Paleozoic-Cenozoic strata in this basin,and these provide a crucial window to a greater understanding of the amalgamation process and source-to-sink relationships between the Alxa Block and surrounding tectonic units.However,due to intensive post-depositional modification,and lack of subsurface data,several fundamental issues-including the distribution and evolution of the depositional systems,provenance supplies and source-to-sink relationships during the Carboniferous-Permian remain unclear and thus hinder hydrocarbon exploration and limit the geological understanding of this basin.Employing integrated outcrop surveys,new drilling data,and detrital zircon dating,this study examines the paleogeographic distribution and evolution,and provenance characteristics of the Carboniferous-Permian strata in the Bayanhot Basin.Our results show that the Bayanhot Basin experienced a long-term depositional evolution process from transgression to retrogression during the Carboniferous-late Permian.The transgression extent could reach the central basin in the early Carboniferous.The maximum regional transgression occurred in the early Permian and might connect the Qilian and North China seas with each other.Subsequently,a gradual regression followed until the end of the Permian.The northwestern NCC appeared as a paleo-uplift area and served as a sediments provenance area for the Alxa Block at that time.The NCC,Bayanwula Mountain,and NQOB jointly served as major provenances during the Carboniferous-Permian.There was no ocean separation,nor was there an orogenic belt between the Alxa Block and the NCC that provided sediments for both sides during the Carboniferous-Permian.The accretion of the Alxa and North China blocks should have been completed before the Carboniferous period.展开更多
Based on the compilation and analysis of the lithofacies and paleogeography distribution maps at present and paleoplate locations during six key geological periods of the Mesozoic and Cenozoic,the lithofacies and pale...Based on the compilation and analysis of the lithofacies and paleogeography distribution maps at present and paleoplate locations during six key geological periods of the Mesozoic and Cenozoic,the lithofacies and paleogeography features and their development laws were expounded.Based on our previous research results on lithofacies and paleogeography from Precambrian to Paleozoic,we systematically studied the features and evolution laws of global lithofacies and paleogeography from the Precambrian and their effects on the formation of source rocks,reservoirs,cap rocks and the distribution of oil and gas worldwide.The results show that since Precambrian,the distribution areas of uplift erosion and terrestrial clastic deposition tended to increase gradually,and increased significantly during the period of continental growth.The scale of coastal and shallow marine facies area had three distinct cycles,namely,from Precambrian to Devonian,from Carboniferous to Triassic,and from Jurassic to Neogene.Correspondingly,the development of shallow carbonate platform also showed three cycles;the lacustrine facies onshore was relatively developed in Mesozoic and Cenozoic;the sabkha was mainly developed in the Devonian,Permian and Triassic.The Cretaceous is the most important source rock layers in the world,followed by the Jurassic and Paleogene source rocks;the clastic reservoirs have more oil and gas than the carbonate reservoirs;the basins with shale caprocks have the widest distribution,the most abundant reserves of oil and gas,and the evaporite caprocks have the strongest sealing capacity,which can seal some huge oil and gas fields.展开更多
In recent years, natural gas exploration in the Sinian Dengying Formation and shale gas exploration in Doushantuo Formation have made major breakthroughs in the Sichuan Basin and its adjacent areas. However, the sedim...In recent years, natural gas exploration in the Sinian Dengying Formation and shale gas exploration in Doushantuo Formation have made major breakthroughs in the Sichuan Basin and its adjacent areas. However, the sedimentary background of the Doushantuo Formation hasn't been studied systematically. The lithofacies paleogeographic pattern, sedimentary environment, sedimentary evolution and distribution of source rocks during the depositional stage of Doushantuo Formation were systematically analyzed by using a large amount of outcrop data, and a small amount of drilling and seismic data.(1) The sedimentary sequence and stratigraphic distribution of the Sinian Doushantuo Formation in the middle-upper Yangtze region were controlled by paleouplifts and marginal sags. The Doushantuo Formation in the paleouplift region was overlayed with thin thickness, including shore facies, mixed continental shelf facies and atypical carbonate platform facies. The marginal sag had complete strata and large thickness, and developed deep water shelf facies and restricted basin facies.(2) The Doushantuo Formation is divided into four members from bottom to top, and the sedimentary sequence is a complete sedimentary cycle of transgression–high position–regression. The first member is atypical carbonate gentle slope deposit in the early stage of the transgression, the second member is shore-mixed shelf deposit in the extensive transgression period, and the third member is atypical restricted–open sea platform deposit of the high position of the transgression.(3) The second member has organic-rich black shale developed with stable distribution and large thickness, which is an important source rock interval and major shale gas interval. The third member is characterized by microbial carbonate rock and has good storage conditions which is conducive to the accumulation of natural gas, phosphate and other mineral resources, so it is a new area worthy of attention. The Qinling trough and western Hubei trough are favorable areas for exploration of natural gas(including shale gas) and mineral resources such as phosphate and manganese ore.展开更多
基金Supported by the China National Science and Technology Major Project(2016ZX05004-002)PetroChina Science and Technology Major Project(2021DJ0501)。
文摘To predict the large-scale source rock and reservoir distribution in Cambrian subsalt formations(Upper Sinian to Mid-Cambrian)in the Tarim Basin,more than 502D seismic lines and 3D data volume acquired latest,22 wells and some out-crops around this area were used to study the tectonic-lithofacies paleogeography,define the distribution of large scale source rocks and reservoirs,and sort out favorable zones.(1)The basin experienced evolution from ramp to deep-water mud-rich ramp,low-gradient slope,weak rimmed to strong rimmed platform,and the differentiation in the platform was controlled by pre-Cambrian palaeo-rifts.(2)The Luonan-Yubei ancient rift controlled the distribution of source rocks in the Lower Cambrian Yuertusi Formation,and this rift together with the northern depression are the main source rock area.(3)There are three sets of large-scale reservoirs,the Upper Sinian Qigebulake Formation,the Lower Cambrian Xiaorbulake Formation and the Wu-songger Formation,and shoal-mounds,early dolomitization and multi-levels of unconformities controlled reservoir develop-ment.(4)Four favorable zones,the north slope of Tazhong,upper slope of Maigaiti area,Keping-Wensu periphery,and south slope of Tabei,were evaluated.Of them,the north slope of Tazhong is most likely to have exploration breakthrough;the south slope of Tabei is the best area for exploring the Upper Sinian large scale weathering crust dolomite;Maigaiti slope and Kep-ing-Wensu periphery area improved in exploration potentials significantly,and are worth prospecting faster.
基金financially supported by the “13th Five-Year Plan” National Science and Technology Major Projects(No. 2016ZX05002006-005)the National Natural Science Foundation of China (No. 41502147)the Sichuan Provincial University “nonconventional oil and gas” scientific research and innovation team construction plan
文摘Sand-rich tight sandstone reservoirs are potential areas for oil and gas exploration. However, the high ratio of sandstone thickness to that of the strata in the formation poses many challenges and uncertainties to traditional lithofacies paleogeography mapping. Therefore, the prediction of reservoir sweet spots has remained problematic in the field of petroleum exploration. This study provides new insight into resolving this problem, based on the analyses of depositional characteristics of a typical modern sand-rich formation in a shallow braided river delta of the central Sichuan Basin, China. The varieties of sand-rich strata in the braided river delta environment include primary braided channels,secondary distributary channels and the distribution of sediments is controlled by the successive superposed strata deposited in paleogeomorphic valleys. The primary distributary channels have stronger hydrodynamic forces with higher proportions of coarse sand deposits than the secondary distributary channels. Therefore, lithofacies paleogeography mapping is controlled by the geomorphology, valley locations, and the migration of channels. We reconstructed the paleogeomorphology and valley systems that existed prior to the deposition of the Xujiahe Formation. Following this, rock-electro identification model for coarse skeletal sand bodies was constructed based on coring data. The results suggest that skeletal sand bodies in primary distributary channels occur mainly in the valleys and low-lying areas,whereas secondary distributary channels and fine deposits generally occur in the highland areas. The thickness distribution of skeletal sand bodies and lithofacies paleogeography map indicate a positive correlation in primary distributary channels and reservoir thickness. A significant correlation exists between different sedimentary facies and petrophysical properties. In addition, the degree of reservoir development in different sedimentary facies indicates that the mapping method reliably predicts the distribution of sweet spots. The application and understanding of the mapping method provide a reference for exploring tight sandstone reservoirs on a regional basis.
基金This work was supported by the Natural Science Foundation of China (NSFC) (grant No. 40232024);Chinese Geological Survey (grant No. 1212010611801) ;Ministry of Science and Technology of China (grant No. 2001CB711002).
文摘The middle Permian Cryptospirifer fauna (brachiopod) has hitherto been found in more than 30 localities in the Yangtze Platform, South China. Examination of data from various localities shows that it occurs stratigraphically in three intervals in the range from the upper Kungurian to Wordian. In the Baoshan block in western Yunnan the fauna occurs in the basal part of the Daaozi Formation and is of possibly an early Wordian age. Outside China the Cryptospirifer fauna has been reported from central and northwest Iran and central Turkey, where the fauna may have an age around the Wordian/Capitanian boundary. Rapid global warming since the late Early Permian and possession of other suitable environmental factors such as proper substrate, clastic input and water depth enabled the Gondwana-derived Baoshan Block and related tectono-stratigraphic units in Iran and Turkey to host the Cryptospirifer fauna, a fauna evolved in the Yangtze Platform that is a type area of the Cathaysian province.
基金partially supported by the National Natural Science Foundation of China(Grant No.4187020378).
文摘Paleogeography is the merger of lithology,depositional environments,tectonic plate movements,topography,climate patterns and ecosystems(reefs,vegetation)through time(e.g.,Scotese,2014,2016,2017;Blakey,2019).The construction of paleogeographic maps using tectonic plate reconstructions requires a multi-year community effort that shares databases,standards and computer projection methods.
基金granted by the National Natural Science Foundation of China(Grant No.41802126)Open Fund of Key Laboratory of Sedimentary Mineralization and Sedimentary Minerals in Shandong Province(Grant No.DMSM2017006).
文摘Paleogeographic analysis accounts for an essential part of geological research,making important contributions in the reconstruction of depositional environments and tectonic evolution histories(Ingalls et al.,2016;Merdith et al.,2017),the prediction of mineral resource distributions in continental sedimentary basins(Sun and Wang,2009),and the investigation of climate patterns and ecosystems(Cox,2016).
基金supported by the Project of the Mesozoic Tectonic Lithofacies Paleogeographic Mapping and Synthesize Research in Qinghai-Tibet Plateau, China Geological Survey(CGS),Ministry of Land and Resources, Project No-1212010610101the Project of the Typical Stratigraphical Sections Research in Qinghai-Tibet Plateau,CGS , Project No-1212011121257
文摘The Triassic petrostratigraphic system and chronologic stratigraphic sketch have been updated and perfected in the Qiangtang area, Qinghai-Tibet Plateau based on the integrated 1:250000 regional geological survey and the latest research progeny. The first finished 1:3000000 Triassic tectonic lithofacies paleogeographic maps in the Qiangtang area shows that the Triassic tectonic unit in the Qiangtang area can been divided into three parts from north to south: northern Qiangtang block; Longmucuo-Shuanghu suture zone; and southern Qiangtang block. The early-middle Triassic tectonic paleogeography in the Qiangtang area is divides into three sub- units: northern Qiangtang passive continental marginal basin (NQPB), Longmucuo- Shuanghu residual basin (LSRB) and southern Qiangtang residual basin (SQRB). The NQPB can be subdivided into four paleogeography units: The Tanggula-Zangxiahe shallow and bathyal sea; The Wangquanhe- Yingshuiquan carbonate platform; The Rejuechaka-Jiangaidarina littoral- shallow sea; and Qiangtang central uplift. The above units of The NQPB possess EW trend, geomorphology high in the south and low in the north, the seawater depth northward. The basinal paleo-current direction is unidirectional, and basinal tectonic subsidence center is in accord with the depo-center, located in the Tanggula-Zangxiahe belt, north of the basin. The sedimentation and tectonic evolution of the NQPB are characterized with passive continental marginal basin. The Qiangtang central orogenic denuded area (ancient land) may be as a sedimentary materials source of the NQPB. SQRB can be divided into two units: Duoma carbonate platform and southern Qiangtang neritic-deep sea. The late Triassic tectonic paleogeography in the Qiangtang area is the framework of the "archipelagic-sea" as a whole, and it may be divided into three sub-units: northern Qiangtang back- arc foreland basin(NQFB), Longmucuo-Shuanghu residual basin(LSRB) and southern Qiangtang marginal-sea basin(SQMB). Thereinto, NQFB can be divided into five paleogeography units: the Zangxiahe-Mingjinghu bathyal basin characterized with the flysch; the Tanggula shallow-sea shelf with the fine-clastics; the Juhuashang platform with carbonates; the Tumenggela-Shuanghu coastal- delta with coal-bearing clastics and the Nadigangri- Geladandong arc with volcanics and tuffs. In transverse section, the NQFB fills is wedge-shaped, and the sediments characterized with thicker in north and thinner in south, and with double materials derived from the Ruolagangri orogenic belt in north and the Shuanghu central orogenic belt in south. The late Triassic depocenter of NQFB is located in the middle of the basin, the Yakecuo-Bandaohu-Quemocuo belt, but the subsidence center in the north, the Zangxiahe- Mingjinghu belt, and basinal tectonic subsidence center not concordant with the depo-center. Late Triassic, the SQMB may be divided into three sub-units: Xiaochaka shallow-sea; Riganpeicuo platform~ and South Qiangtang southern bathyal basin. In transverse section, the basement of the SQMB is characterized with low in the northern and southern, but high in the middle; forming wedge shaped sediments with thicker in the north and thinner in the south; the sedimentary materials derived from the Qiangtang central uplift and Nadigangri arcs in north. The late Triassic subsidence centre of the SQMB is located in the northern (Xiaochaka area), but the depocenter in the southern (Qixiancuo Suobucha area). The sedimentation and tectonic evolution of the SQMB are characterized with marginal sea.
基金supported by the Australian Research Council(Grant No.IH130200012)Alfred P Sloan Foundation(Grant Nos.G-2017-9997 and G-2018-11296)through the Deep Carbon Observatory.
文摘Major advances in computational power,as well as community modelling workflows and an improvement in data availability,has revolutionized Earth sciences over the last decade.Geological data has been synthesized into flexible and open access plate tectonic and paleogeographic reconstructions using the open-source and cross-platform GPlates(www.gplates.org)software since 2008(Muller et al.,2018;Muller et al.,2008).
基金This research was supported by the Project for the Survey of Land and Resources in China(1212010633901)National Natural Science Foundation of China(Grant No.41572090)。
文摘There are 9 major coal-accumulating periods during geological history in China,including the Early Carboniferous,Late Carboniferous-Early Permian,Middle Permian,Late Permian,Late Triassic,Early-Middle Jurassic,Early Cretaceous,Paleogene and Neogene.The coal formed in these periods were developed in different coal-accumulating areas(CAA)including the North China,South China,Northwest China,Northeast China,the Qinghai–Tibet area,and China offshore area.In this paper,we investigated depositional environments,sequence stratigraphy,lithofacies paleogeography and coal accumulation pattern of five major coal-accumulating periods including the Late Carboniferous to Middle Permian of the North China CAA,the Late Permian of the South China CAA,the Late Triassic of the South China CAA,the Early-Middle Jurassic of the North and Northwest China CAA,and the Early Cretaceous in the Northeast China CAA.According to distribution of the coal-bearing strata and the regional tectonic outlines,we have identified distribution range of the coal-forming basins,sedimentary facies types and coal-accumulating models.The sequence stratigraphic frameworks of the major coal-accumulating periods were established based on recognition of a variety of sequence boundaries.The distribution of thick coals and migration patterns of the coal-accumulating centers in the sequence stratigraphic framework were analyzed.The lithofacies paleogeography maps based on third-order sequences were reconstructed and the distribution of coal accumulation centers and coal-rich belts were predicted.
基金sponsored by the National Natural Science Foundation of China(Grant No.4187020378).
文摘The Central-east Asian continent,in which China is presently located,is a composite terrane composed of many small or micro-scale blocks and orogenic belts (Ren et al.,1999).Compared with large-scale cratons such as North America and Siberia,the blocks that make up China are much smaller.For example,the North China and Siberian blocks,as well as some part of the ancient African continent,belonged to part of the Colombia supercontinent and connected with Baltica (Rogers and Santosh,2002;Lu et al.,2002).After major rifting episodes at 1.8-1.6 Ga.
基金supported by a grant from 2015 Research Fund of Andong National University
文摘A new species of the probable calcareous alga Amsassia, A. koreanensis, is recognized from the Duwibong Formation (Middle Ordovician, Darriwilian) of the Taebaeksan Basin in mid-eastern Korea. This is the first report of the genus from the Korean Peninsula, expanding its geographical range to the eastern Sino-Korean Block. The new species also occurs in the Xiazhen Formation (Upper Ordovician, Katian) at Zhuzhai in the South China Block. Amsassia koreanensis is the smallest species of this modular genus, having a maximum module diameter of 0.28 ram. Module increase is by bipartite, tripartite and quadripartite types of longitudinal axial fission, but unlike other species of the genus, quadripartite fission is common. The types of fission are comparable to those in some Tetradiida (now Prismostylales, florideophycean rhodophyte algae), although the processes of fission are different. The distribution of A. koreanensis further strengthens the biogeographical connection between the Sino-Korean and South China blocks, suggesting that these two paleocontinents were located closer together during the Middle to Late Ordovician than previously speculated.
基金supported by National Key R&D Program Project of China(Grant No.2017YFC0603106)the Opening Foundation of State Key Laboratory of Continental Dynamics,Northwest University,China(Grant No.201210140)。
文摘The Bayanhot Basin is a superimposed basin that experienced multiple-staged tectonic movements;it is in the eastern Alxa Block,adjacent to the North China Craton(NCC)and the North Qilian Orogenic Belt(NQOB).There are well-developed Paleozoic-Cenozoic strata in this basin,and these provide a crucial window to a greater understanding of the amalgamation process and source-to-sink relationships between the Alxa Block and surrounding tectonic units.However,due to intensive post-depositional modification,and lack of subsurface data,several fundamental issues-including the distribution and evolution of the depositional systems,provenance supplies and source-to-sink relationships during the Carboniferous-Permian remain unclear and thus hinder hydrocarbon exploration and limit the geological understanding of this basin.Employing integrated outcrop surveys,new drilling data,and detrital zircon dating,this study examines the paleogeographic distribution and evolution,and provenance characteristics of the Carboniferous-Permian strata in the Bayanhot Basin.Our results show that the Bayanhot Basin experienced a long-term depositional evolution process from transgression to retrogression during the Carboniferous-late Permian.The transgression extent could reach the central basin in the early Carboniferous.The maximum regional transgression occurred in the early Permian and might connect the Qilian and North China seas with each other.Subsequently,a gradual regression followed until the end of the Permian.The northwestern NCC appeared as a paleo-uplift area and served as a sediments provenance area for the Alxa Block at that time.The NCC,Bayanwula Mountain,and NQOB jointly served as major provenances during the Carboniferous-Permian.There was no ocean separation,nor was there an orogenic belt between the Alxa Block and the NCC that provided sediments for both sides during the Carboniferous-Permian.The accretion of the Alxa and North China blocks should have been completed before the Carboniferous period.
基金Supported by the China National Science and Technology Major Project(2011ZX05028-003,2016ZX05029-001).
文摘Based on the compilation and analysis of the lithofacies and paleogeography distribution maps at present and paleoplate locations during six key geological periods of the Mesozoic and Cenozoic,the lithofacies and paleogeography features and their development laws were expounded.Based on our previous research results on lithofacies and paleogeography from Precambrian to Paleozoic,we systematically studied the features and evolution laws of global lithofacies and paleogeography from the Precambrian and their effects on the formation of source rocks,reservoirs,cap rocks and the distribution of oil and gas worldwide.The results show that since Precambrian,the distribution areas of uplift erosion and terrestrial clastic deposition tended to increase gradually,and increased significantly during the period of continental growth.The scale of coastal and shallow marine facies area had three distinct cycles,namely,from Precambrian to Devonian,from Carboniferous to Triassic,and from Jurassic to Neogene.Correspondingly,the development of shallow carbonate platform also showed three cycles;the lacustrine facies onshore was relatively developed in Mesozoic and Cenozoic;the sabkha was mainly developed in the Devonian,Permian and Triassic.The Cretaceous is the most important source rock layers in the world,followed by the Jurassic and Paleogene source rocks;the clastic reservoirs have more oil and gas than the carbonate reservoirs;the basins with shale caprocks have the widest distribution,the most abundant reserves of oil and gas,and the evaporite caprocks have the strongest sealing capacity,which can seal some huge oil and gas fields.
基金Supportd by the China National Science and Technology Major Project(2016ZX05004-001)
文摘In recent years, natural gas exploration in the Sinian Dengying Formation and shale gas exploration in Doushantuo Formation have made major breakthroughs in the Sichuan Basin and its adjacent areas. However, the sedimentary background of the Doushantuo Formation hasn't been studied systematically. The lithofacies paleogeographic pattern, sedimentary environment, sedimentary evolution and distribution of source rocks during the depositional stage of Doushantuo Formation were systematically analyzed by using a large amount of outcrop data, and a small amount of drilling and seismic data.(1) The sedimentary sequence and stratigraphic distribution of the Sinian Doushantuo Formation in the middle-upper Yangtze region were controlled by paleouplifts and marginal sags. The Doushantuo Formation in the paleouplift region was overlayed with thin thickness, including shore facies, mixed continental shelf facies and atypical carbonate platform facies. The marginal sag had complete strata and large thickness, and developed deep water shelf facies and restricted basin facies.(2) The Doushantuo Formation is divided into four members from bottom to top, and the sedimentary sequence is a complete sedimentary cycle of transgression–high position–regression. The first member is atypical carbonate gentle slope deposit in the early stage of the transgression, the second member is shore-mixed shelf deposit in the extensive transgression period, and the third member is atypical restricted–open sea platform deposit of the high position of the transgression.(3) The second member has organic-rich black shale developed with stable distribution and large thickness, which is an important source rock interval and major shale gas interval. The third member is characterized by microbial carbonate rock and has good storage conditions which is conducive to the accumulation of natural gas, phosphate and other mineral resources, so it is a new area worthy of attention. The Qinling trough and western Hubei trough are favorable areas for exploration of natural gas(including shale gas) and mineral resources such as phosphate and manganese ore.