Objective The development of continental rifting and seafloor spreading can be predominated by magmatic upwelling （magma-rich） or tectonic stretching （magma-poor）. Located in the terminal portion of propagating s...Objective The development of continental rifting and seafloor spreading can be predominated by magmatic upwelling （magma-rich） or tectonic stretching （magma-poor）. Located in the terminal portion of propagating seafloor spreading of the South China Sea （SCS）, the southwestern mid-ridge of the southwest sub-basin （SWSB） of the SCS was found with much thin crust and numerous faulted blocks coupling with magma-poor continental margins along its flanks. Therefore, the southwestern part of the SWSB is most likely to be a tectonic-dominated basin. To justify the hypothesis with further evidence, we investigated the nature of seamounts on the southwestern mid-ridge of the SWSB which may inherit seafloor spreading.展开更多
A systematic study of early Paleozoic S-type granites in Pinghe enhances our understanding of the tectonic evolution of proto-Tethys and provides a foundation for exploring rare metal deposits in the region.The Pinghe...A systematic study of early Paleozoic S-type granites in Pinghe enhances our understanding of the tectonic evolution of proto-Tethys and provides a foundation for exploring rare metal deposits in the region.The Pinghe granites consist of monzogranite and leucogranite.Zircon U-Pb dating shows that the emplacement ages of the monzogranite and leucogranite are 502.0 Ma and 500.9 Ma,respectively.All samples have high SiO_(2) content and a weakly to strongly peraluminous character(A/CNK=1.08-1.23),consistent with S-type granites.The monzogranite has relatively high CaO,Sr,Ba,and CaO/Na_(2)O ratios but lower Rb.In contrast,the leucogranite has lower CaO,Sr,Ba,and CaO/Na_(2)O ratios but higher Rb.The similar ε_(Nd)(t)values(−9.3 to−8.4)and Pb isotopic compositions((^(206)Pb/^(204)Pb)t=18.03-19.36,(^(207)Pb/^(204)Pb)t=15.66-15.76,(^(208)Pb/^(204)Pb)t=37.97-38.55)suggest that the monzogranite formed through partial melting of crustal greywacke,while the leucogranite originated from partial melting of crustal pelite.Regional geological studies suggest that these S-type granites in Pinghe were emplaced in an active continental margin setting,associated with the westward subduction of the proto-Tethys oceanic slab.The geochemical characteristics of leucogranite are consistent with those of tungsten-tin-related granites,indicating significant metallogenic potential for W and Sn deposits.展开更多
The traditional binary hydrocarbon-generation patterns are inadequate for accurately evaluating the hydrocarbongeneration potential of different types of source rocks in the Permian Pusige Formation in the piedmont of...The traditional binary hydrocarbon-generation patterns are inadequate for accurately evaluating the hydrocarbongeneration potential of different types of source rocks in the Permian Pusige Formation in the piedmont of southwestern Tarim Basin,especially the resource potential of light oil and condensate.We selected the Pusige Formation source rocks from the piedmont of southwestern Tarim Basin to conduct closed gold tube pyrolysis experiments,recovered the hydrocarbon-generation process under geological conditions using the method of hydrocarbon-generation kinetics,and established multi-component hydrocarbon-generation patterns of source rocks with three quality levels.The results show that the total hydrocarbon yields of good(TOC=1.35%),fair(TOC=0.70%),and poor(TOC=0.24%)source rocks are 648,236 and 108 mg/g,respectively.The good source rock shows more concentrate oil-generation process,while fair source rock has stronger dry gas potential at the high-maturity stage.Furthermore,based on the characteristics of hydrocarbon generation of the Pusige Formation source rocks,the formation and evolution of oil and gas can be divided into the immature,and heavy hydrocarbon,light hydrocarbon,wet gas,and dry gas generation stages.The proposed multi-component hydrocarbon-generation patterns are used to evaluate the hydrocarbon-generation potential and resources of different reservoirs.The resources of heavy oil,light oil,wet gas,and dry gas generated by the Pusige Formation source rocks in the study area are estimated to be 225×10^(8) t,150×10^(8) t,3×10^(12) m^(3) and 6×10^(12) m^(3),respectively.The Pusige Formation source rocks in the piedmont of southwestern Tarim Basin exhibit great hydrocarbon-generation potential,providing the material foundation for forming large oil and gas fields.This area rich in light resources is promising for future petroleum exploration,and it is expected to become a national resource strategic base in China.展开更多
1.Objective,The Cretaceous succession is characteristic of the aeolian sedimentary system in the Ordos Basin,which is the major ore-bearing layer for the sandstone-type uranium deposits.Based on the research of paleon...1.Objective,The Cretaceous succession is characteristic of the aeolian sedimentary system in the Ordos Basin,which is the major ore-bearing layer for the sandstone-type uranium deposits.Based on the research of paleontology and magnetostratigraphy,formers believed it belonged to the Early Cretaceous(Huang YB,2010).However,the lack of intrusions or volcanic rocks for isotopic dating results in an unclear formation age for the Lower Cretaceous succession.Recently,tuffs were firstly discovered in the Luohandong Formation in the Zhenyuan area,Gansu Province,located in the southwestern Ordos Basin,China.The LA-ICP-MS zircon U-Pb dating of tuffs was carried out.The new ages can precisely constrain the depositional age of the Luohandong Formation and also provide significant indications for the study of regional volcanic activities,paleoclimate,basin evolution,and tectonic setting.展开更多
According to the particularity of towns＇ construction in the southwestern mountainous areas of Yunnan Province, this study has built constructive land suit- ability evaluation index system which is different to flat ...According to the particularity of towns＇ construction in the southwestern mountainous areas of Yunnan Province, this study has built constructive land suit- ability evaluation index system which is different to flat area. Then this study deter- mined single evaluation factors index and comprehensive suitability index using ＂ex- treme conditions method＂ and ＂suitability index method＂, and analyzed and assessed the constructive land suitability on each evaluation unit polygons and its suitability level by using GIS software. Taking Lianghe County of Dehong Dai-Jingpo Au- tonomous Prefecture as an example to evaluate land suitability in Lianghe County＇s main towns around the gentle slope, the results show, in the evaluation area, the area of land suitable for construction and unsuitable for construction respectively ac- count 73.58% and 26.42%. And first-class, second and third-class of land suitable for construction should be composited at the ratio of about 11：49：40. The suitability evaluation index system and method developed in this paper is applicable for evalu- ating the construction land suitability in mountainous areas of southwest Yunnan Province, and will provide theoretical and technical support for land policy measures which strengthen the protection of farmland and promote the scientific development of urbanization in Yunnan Province and even similar mountainous areas of the whole China.展开更多
The limestone area located in southwestern Guangxi in the south of China is part of a global biodiversity hotspot. As an important habitat of this limestone region, karst wetlands provide birds with necessary water co...The limestone area located in southwestern Guangxi in the south of China is part of a global biodiversity hotspot. As an important habitat of this limestone region, karst wetlands provide birds with necessary water conditions for their survival and reproduction. From 2007 to 2012, bird surveys were conducted in natural wetlands(pools, streams, springs and seasonal flows) in 14 nature reserves and 18 reservoirs in the limestone area of southwestern Guangxi. A total of 365 bird species were recorded in field investigations, including 103 water-dependent birds mainly seen in wetlands. Among these 103 birds, 10 species are globally threatened and 5 species have been placed under national key protection. The birds were selective in their use of the various types of karst wetlands. The number of bird species was the highest in pools and springs, with 304 and 266 respectively, followed by streams with 131 species. Reservoirs are the main wintering habitat for the large Natatores and in the rainy season the importance of seasonal flows is paramount. Seasonal changes in the utilization of karst wetlands by birds were obvious; the number of bird species in the dry season was much higher than during the rainy season. Bird migration and seasonal flows are the main reasons for seasonal variation in the number of water-dependent birds. These natural karst wetlands ensure the drinking water supply for more than 80% of the water-independent birds in the dry season. These karst wetlands are the wintering ground and stopover area for 58 species of migrant birds. At present, threats to the birds in the karst wetlands consist of illegal hunting, habitat changes and eucalyptus plantations. Karst wetlands are important for protecting biodiversity. More attention ought to be directed to these wetlands and protection efforts enhanced.展开更多
An adult Asian Open-billed Stork (Anastomus oscitans) was observed in the Longjing reservoir of Baise City, northwestern Guangxi Zhuang Autonomous Region on 3 October 2010. It is the first record of this big stork in ...An adult Asian Open-billed Stork (Anastomus oscitans) was observed in the Longjing reservoir of Baise City, northwestern Guangxi Zhuang Autonomous Region on 3 October 2010. It is the first record of this big stork in Guangxi, southwestern ChinaThe Longjing reservoir is located in the展开更多
The special issue deals with the Cretaceous-Tertiary deserts in southwestern China and relevant sedimentological problems about deserts. The study area is located between 101°10＇- 107°00＇E and 28°00＇...The special issue deals with the Cretaceous-Tertiary deserts in southwestern China and relevant sedimentological problems about deserts. The study area is located between 101°10＇- 107°00＇E and 28°00＇-30°40′ N. The ancient desert study is so little in China that there has not been a systematic report about it up to now. Based on the study in many ways on Cretaceous-Tertiary deserts in southwestern China, plentiful data have been obtained. Though it is still a bit rough, the study is a good beginning of the ancient desert study in China. The main ideas and conclusions are summarized as follows.展开更多
基金financially supported by the National Natural Science Foundation of China (grants No.91328205, 41376062 and 41206039)the Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology (grant No.MGQNLMKF201708)726 Plan (grant No.GZH201100205)
文摘Objective The development of continental rifting and seafloor spreading can be predominated by magmatic upwelling （magma-rich） or tectonic stretching （magma-poor）. Located in the terminal portion of propagating seafloor spreading of the South China Sea （SCS）, the southwestern mid-ridge of the southwest sub-basin （SWSB） of the SCS was found with much thin crust and numerous faulted blocks coupling with magma-poor continental margins along its flanks. Therefore, the southwestern part of the SWSB is most likely to be a tectonic-dominated basin. To justify the hypothesis with further evidence, we investigated the nature of seamounts on the southwestern mid-ridge of the SWSB which may inherit seafloor spreading.
基金funded by the Science and Technology Department of Yunnan Province(202303AA080006)the National Natural Science Foundation of China(41972312 and 41672329).
文摘A systematic study of early Paleozoic S-type granites in Pinghe enhances our understanding of the tectonic evolution of proto-Tethys and provides a foundation for exploring rare metal deposits in the region.The Pinghe granites consist of monzogranite and leucogranite.Zircon U-Pb dating shows that the emplacement ages of the monzogranite and leucogranite are 502.0 Ma and 500.9 Ma,respectively.All samples have high SiO_(2) content and a weakly to strongly peraluminous character(A/CNK=1.08-1.23),consistent with S-type granites.The monzogranite has relatively high CaO,Sr,Ba,and CaO/Na_(2)O ratios but lower Rb.In contrast,the leucogranite has lower CaO,Sr,Ba,and CaO/Na_(2)O ratios but higher Rb.The similar ε_(Nd)(t)values(−9.3 to−8.4)and Pb isotopic compositions((^(206)Pb/^(204)Pb)t=18.03-19.36,(^(207)Pb/^(204)Pb)t=15.66-15.76,(^(208)Pb/^(204)Pb)t=37.97-38.55)suggest that the monzogranite formed through partial melting of crustal greywacke,while the leucogranite originated from partial melting of crustal pelite.Regional geological studies suggest that these S-type granites in Pinghe were emplaced in an active continental margin setting,associated with the westward subduction of the proto-Tethys oceanic slab.The geochemical characteristics of leucogranite are consistent with those of tungsten-tin-related granites,indicating significant metallogenic potential for W and Sn deposits.
基金Supported by National Key Research and Development Program(2025ZD1400505)Science and Technology Project of China National Petroleum Corporation(2023ZZ14YJ02)+1 种基金Innovation Team Project of Xinjiang Uyghur Autonomous Region(2024TSYCTD0008)Project of Theory of Hydrocarbon Enrichment under Multi-Sphere Interactions of the Earth(THEMSIE04010104).
文摘The traditional binary hydrocarbon-generation patterns are inadequate for accurately evaluating the hydrocarbongeneration potential of different types of source rocks in the Permian Pusige Formation in the piedmont of southwestern Tarim Basin,especially the resource potential of light oil and condensate.We selected the Pusige Formation source rocks from the piedmont of southwestern Tarim Basin to conduct closed gold tube pyrolysis experiments,recovered the hydrocarbon-generation process under geological conditions using the method of hydrocarbon-generation kinetics,and established multi-component hydrocarbon-generation patterns of source rocks with three quality levels.The results show that the total hydrocarbon yields of good(TOC=1.35%),fair(TOC=0.70%),and poor(TOC=0.24%)source rocks are 648,236 and 108 mg/g,respectively.The good source rock shows more concentrate oil-generation process,while fair source rock has stronger dry gas potential at the high-maturity stage.Furthermore,based on the characteristics of hydrocarbon generation of the Pusige Formation source rocks,the formation and evolution of oil and gas can be divided into the immature,and heavy hydrocarbon,light hydrocarbon,wet gas,and dry gas generation stages.The proposed multi-component hydrocarbon-generation patterns are used to evaluate the hydrocarbon-generation potential and resources of different reservoirs.The resources of heavy oil,light oil,wet gas,and dry gas generated by the Pusige Formation source rocks in the study area are estimated to be 225×10^(8) t,150×10^(8) t,3×10^(12) m^(3) and 6×10^(12) m^(3),respectively.The Pusige Formation source rocks in the piedmont of southwestern Tarim Basin exhibit great hydrocarbon-generation potential,providing the material foundation for forming large oil and gas fields.This area rich in light resources is promising for future petroleum exploration,and it is expected to become a national resource strategic base in China.
基金supported by the Science&Technology Fundamental Resources Investigation Program of China(2022FY101800)the National Science Foundation of China(92162212)the International Geoscience Programme(IGCP 675).
文摘1.Objective,The Cretaceous succession is characteristic of the aeolian sedimentary system in the Ordos Basin,which is the major ore-bearing layer for the sandstone-type uranium deposits.Based on the research of paleontology and magnetostratigraphy,formers believed it belonged to the Early Cretaceous(Huang YB,2010).However,the lack of intrusions or volcanic rocks for isotopic dating results in an unclear formation age for the Lower Cretaceous succession.Recently,tuffs were firstly discovered in the Luohandong Formation in the Zhenyuan area,Gansu Province,located in the southwestern Ordos Basin,China.The LA-ICP-MS zircon U-Pb dating of tuffs was carried out.The new ages can precisely constrain the depositional age of the Luohandong Formation and also provide significant indications for the study of regional volcanic activities,paleoclimate,basin evolution,and tectonic setting.
基金Supported by National Natural Science Foundation of China(41261018)Lianghe Government Authorized Project~~
文摘According to the particularity of towns＇ construction in the southwestern mountainous areas of Yunnan Province, this study has built constructive land suit- ability evaluation index system which is different to flat area. Then this study deter- mined single evaluation factors index and comprehensive suitability index using ＂ex- treme conditions method＂ and ＂suitability index method＂, and analyzed and assessed the constructive land suitability on each evaluation unit polygons and its suitability level by using GIS software. Taking Lianghe County of Dehong Dai-Jingpo Au- tonomous Prefecture as an example to evaluate land suitability in Lianghe County＇s main towns around the gentle slope, the results show, in the evaluation area, the area of land suitable for construction and unsuitable for construction respectively ac- count 73.58% and 26.42%. And first-class, second and third-class of land suitable for construction should be composited at the ratio of about 11：49：40. The suitability evaluation index system and method developed in this paper is applicable for evalu- ating the construction land suitability in mountainous areas of southwest Yunnan Province, and will provide theoretical and technical support for land policy measures which strengthen the protection of farmland and promote the scientific development of urbanization in Yunnan Province and even similar mountainous areas of the whole China.
基金financially supported by the National Natural Science Foundation of China(No.30360012,31172123)the Forestry Department of Guangxi Zhuang Autonomous Region
文摘The limestone area located in southwestern Guangxi in the south of China is part of a global biodiversity hotspot. As an important habitat of this limestone region, karst wetlands provide birds with necessary water conditions for their survival and reproduction. From 2007 to 2012, bird surveys were conducted in natural wetlands(pools, streams, springs and seasonal flows) in 14 nature reserves and 18 reservoirs in the limestone area of southwestern Guangxi. A total of 365 bird species were recorded in field investigations, including 103 water-dependent birds mainly seen in wetlands. Among these 103 birds, 10 species are globally threatened and 5 species have been placed under national key protection. The birds were selective in their use of the various types of karst wetlands. The number of bird species was the highest in pools and springs, with 304 and 266 respectively, followed by streams with 131 species. Reservoirs are the main wintering habitat for the large Natatores and in the rainy season the importance of seasonal flows is paramount. Seasonal changes in the utilization of karst wetlands by birds were obvious; the number of bird species in the dry season was much higher than during the rainy season. Bird migration and seasonal flows are the main reasons for seasonal variation in the number of water-dependent birds. These natural karst wetlands ensure the drinking water supply for more than 80% of the water-independent birds in the dry season. These karst wetlands are the wintering ground and stopover area for 58 species of migrant birds. At present, threats to the birds in the karst wetlands consist of illegal hunting, habitat changes and eucalyptus plantations. Karst wetlands are important for protecting biodiversity. More attention ought to be directed to these wetlands and protection efforts enhanced.
文摘An adult Asian Open-billed Stork (Anastomus oscitans) was observed in the Longjing reservoir of Baise City, northwestern Guangxi Zhuang Autonomous Region on 3 October 2010. It is the first record of this big stork in Guangxi, southwestern ChinaThe Longjing reservoir is located in the
文摘The special issue deals with the Cretaceous-Tertiary deserts in southwestern China and relevant sedimentological problems about deserts. The study area is located between 101°10＇- 107°00＇E and 28°00＇-30°40′ N. The ancient desert study is so little in China that there has not been a systematic report about it up to now. Based on the study in many ways on Cretaceous-Tertiary deserts in southwestern China, plentiful data have been obtained. Though it is still a bit rough, the study is a good beginning of the ancient desert study in China. The main ideas and conclusions are summarized as follows.
