The Zhuxi W(Cu)skarn deposit,the world’s largest tungsten deposit is newly discovered in Jingdezhen city,northeastern Jiangxi province,China.It mainly occurs near the contact zone between the Yanshanian granites and ...The Zhuxi W(Cu)skarn deposit,the world’s largest tungsten deposit is newly discovered in Jingdezhen city,northeastern Jiangxi province,China.It mainly occurs near the contact zone between the Yanshanian granites and the Late Paleozoic carbonate rocks.Three types of mineralization including skarn type,altered granite type and quartz vein veinlet type orebodies have been observed.In this study,the 40Ar 39Ar age of hydrothermal muscovite coexisting with copper mineralization in the altered granite type orebody formed near the unconformity interface is determined by step-heating technology using CO2 laser.The plateau age,isochron age,and inverse isochron age of muscovite are(147.39±0.94)Ma,(147.2±1.5)Ma,and(147.1±1.5)Ma,respectively.These ages are almost identical to the ages of ore-related granite and other mineralization types in the Zhuxi W(Cu)deposit,indicating that the Cu mineralizations occurred at the shallow depth and near the unconformity interface are contemporaneous during the Late Jurassic.This further suggested that the acompanied W and Cu mineralization in the Zhuxi W(Cu)deposit which may be controlled by the magma source is enriched in both W and Cu.展开更多
A series of marine natural gas fields were recently discovered in oolitic dolomites of the Lower Triassic Feixianguan formation, northeastern Sichuan Basin, southwest China. The mechanism forming these reservoir dolom...A series of marine natural gas fields were recently discovered in oolitic dolomites of the Lower Triassic Feixianguan formation, northeastern Sichuan Basin, southwest China. The mechanism forming these reservoir dolomites is debatable, limiting the ability to characterize these reservoir successfully. Based on the investigation of the representative Dukouhe, Luojiazhai, and Puguang areas, this issue was addressed by examining the distribution, petrology, and geochemistry of the dolomites, the most comprehensive study to date was provided. Dolomitization occurred at a very early stage of diagenesis, as shown by the petrological features of the rock fabric. Vadose silt, which is composed primarily of dolomitic clasts, is found in the primary and secondary pores of the oolitic dolomite. This indicates that the overlying strata were subjected to dolomitization when the Feixianguan formation was located in the vadose zone. Therefore, it may be inferred that the dolomitization which occurred before the formation was exposed to meteoric conditions. The spatial distribution and geochemical characteristics of the dolomite indicate that dolomitization occurred as a result of seepage reflux. The degree of dolomitization decreases with increasing distance from the evaporative lagoon. Furthermore, the type and porosity of the dolomite vary in different zones of the upward-shoaling sequence, with the porosity gradually decreasing from the highest layer to the lowest layer. This reflects a close relationship between dolomitization and seawater evaporation during the formation of the dolomite. Geochemical analysis provided further evidence for the relationship between the dolomitization fluid and the coeval seawater. The 87Sr/86Sr and 813C isotopes, as well as the abundances of trace elements, Fe and Mn, indicate that seawater concentrated by evaporation acted as the dolomitization fluid. These results also show that dolomitization most likely occurred in a semi-closed diagenetic environment. Therefore, the main mechanism of oolitic dolomite formation is seepage reflux, which occurred at an early stage of diagenesis.展开更多
For understanding the source and location mechanism of lode gold deposits hosted in metamorphic rocks in northeastern Hunan, the authors analyzed the REE (rare earth elements) in ores and their host rocks, metallogeni...For understanding the source and location mechanism of lode gold deposits hosted in metamorphic rocks in northeastern Hunan, the authors analyzed the REE (rare earth elements) in ores and their host rocks, metallogenic elements in host rocks near and distant from the ore bodies, and characteristics of ore controlling structures, and deduced their genetic implication. Their geochemical features of REE and metallogenic elements suggest that they are formed by mobilization of dispersed metallogenic materials in Lengjiaxi Group of Middle Proterozoic during deformation and metamorphism process, mainly in Wulingian period. From the attributes of ore controlling structures and regularity of location of gold metallization, it is concluded that the location of gold deposits is closely related to reverse shearing. Ore forming fluids are focused on the secondary faults and extension fractures of reverse shear zones of nearly EW strike by stress driven diffusion and seismic pumping.展开更多
The Middle Triassic Ladinian-Upper Triassic Norian series in the Mesozoic-Cenozoic Ruo’ergai basin of Songpan area is characterized of large thick shallow marine-deep marine fine grained clastic.The strata are region...The Middle Triassic Ladinian-Upper Triassic Norian series in the Mesozoic-Cenozoic Ruo’ergai basin of Songpan area is characterized of large thick shallow marine-deep marine fine grained clastic.The strata are regionally unconformable between each adjacent two of the Middle-Late Triassic fine grained clastic,the Jurassic coal-containing clastic,the Cretaceous-Paleogene variegated coarse clastic。展开更多
As the stress concentrated area of the Euro\|Asia and Indian plates collision, Tibet plateau has its special geological structure background.And its evolution has been drawing attentions of more and more geologists.Th...As the stress concentrated area of the Euro\|Asia and Indian plates collision, Tibet plateau has its special geological structure background.And its evolution has been drawing attentions of more and more geologists.The Sino\|French lithoscope group deployed 28 three\|component seismometers in 1998 from Gonghe to Yushu in Qinghai Province. These stations was distributed on most tectonic unit in Eastern Tibet, which are Eastern Qaidam Basin\|Gonghe Basin, Eastern Kunlun Fault\|Maqin Suture,Bayan Har\|Ganzi Terrane,Jinsha Suture and Qiangtang Block from north to south.According to 19 well\|recorded P wave events, after the data processing such as broading the frequence band,integration to get ground motions,then filtering and deconvolution, most stations’ data can achieve good receiver function with clear Ps conversions which show a step\|shaped Moho with southward dipping. The biggest Ps conversions occur 5～9 seconds after P arrival from north to south. Broad peak and its perturbations mean thicker sediments in Gonghe Basin and south of Jinsha Suture. And correspondent inversion shows there are two discontinuous positions where Kunlun Fault and Jinsha Suture are located. The crust thickness is about 55km in Gonghe Basin and nearby, deeper to 70km in Bayan Har Terrane, and 75～80km in the Qiangtang Block. A 20～40km deep low\|velocity zone can be traced along the profile although it is displaced by the faults. In Bayan Har Terrane some stations show a little eastward inclination of Moho due to comparing the receiver function from different back\|azimuth. A model is deduced that support both Qilian Plate and Qiangtang Block’s subduction beneath Bayan Terrane, and do uble\|crust and escape\|structure is therefore possible because of the stress st ate.展开更多
亚中尺度过程是海洋学研究的前沿热点领域,从高分辨率资料中实现亚中尺度信号的快速提取对开展亚中尺度动力学研究具有重要意义。为此,根据亚中尺度过程的物理特性,提出一种基于深度学习的自动识别方法,构建了基于U-Net网络的海洋亚中...亚中尺度过程是海洋学研究的前沿热点领域,从高分辨率资料中实现亚中尺度信号的快速提取对开展亚中尺度动力学研究具有重要意义。为此,根据亚中尺度过程的物理特性,提出一种基于深度学习的自动识别方法,构建了基于U-Net网络的海洋亚中尺度过程识别网络(submesoscale processes automatic identification network, SM-Net),该网络采用视觉几何组网络作为主干特征提取网络并引入改进的混合注意力模块以提升识别能力。基于高分辨率MITgcm (Massachusetts Institute of Technology general circulation model)模式数据,通过SM-Net准确识别出南海东北部全年的亚中尺度过程,并分类为冷涡、暖涡和锋面。南海东北部亚中尺度冷涡、暖涡和锋面均多发生于冬季,夏季的发生频率较低,但吕宋海峡的亚中尺度过程全年均较为活跃。除吕宋海峡外,亚中尺度冷涡夏季多发生于台湾岛西南海域、吕宋岛西南海域和吕宋岛沿岸,冬季多发生于南海北部陆坡陆架区;亚中尺度暖涡夏季多发生于吕宋岛沿岸,冬季在南海北部陆坡陆架区较为活跃;亚中尺度锋面的时空特征与冷涡相似,但黑潮流经区域的发生频率更高。亚中尺度过程罗斯贝数和动能的时空特征与发生频率具有较好的一致性,暖涡的动能、罗斯贝数和直径均弱于冷涡。上述识别方法在南海的成功运用,为应用SWOT (surface water and ocean topography)卫星数据研究亚中尺度过程提供了一定参考。展开更多
基金Project(41873059)supported by the National Natural Science Foundation of ChinaProject(JGMEDB [2017]78)supported by the Jiangxi Geological and Mineral Exploration and Development Bureau Foundation,China+2 种基金Project(2011BAB04B02)supported by the National Science and Technology Support Plan Project,ChinaProject(201411035)supported by the Welfare Research Program of Ministry of Land and Resources,ChinaProject(20150013)supported by Jiangxi Provincial Geological Exploration Fund Management Center,China
文摘The Zhuxi W(Cu)skarn deposit,the world’s largest tungsten deposit is newly discovered in Jingdezhen city,northeastern Jiangxi province,China.It mainly occurs near the contact zone between the Yanshanian granites and the Late Paleozoic carbonate rocks.Three types of mineralization including skarn type,altered granite type and quartz vein veinlet type orebodies have been observed.In this study,the 40Ar 39Ar age of hydrothermal muscovite coexisting with copper mineralization in the altered granite type orebody formed near the unconformity interface is determined by step-heating technology using CO2 laser.The plateau age,isochron age,and inverse isochron age of muscovite are(147.39±0.94)Ma,(147.2±1.5)Ma,and(147.1±1.5)Ma,respectively.These ages are almost identical to the ages of ore-related granite and other mineralization types in the Zhuxi W(Cu)deposit,indicating that the Cu mineralizations occurred at the shallow depth and near the unconformity interface are contemporaneous during the Late Jurassic.This further suggested that the acompanied W and Cu mineralization in the Zhuxi W(Cu)deposit which may be controlled by the magma source is enriched in both W and Cu.
基金Project(2012CB214803)supported by the Major State Basic Research Development Program,ChinaProject(2011ZX5017-001-HZO2)supported by the National Science & Technology Special Project,China+1 种基金Project(2011D-5006-0105)supported by the PetroChina Research Fund,ChinaProject(SZD0414)supported by the Key Subject Construction Project of Sichuan Province,China
文摘A series of marine natural gas fields were recently discovered in oolitic dolomites of the Lower Triassic Feixianguan formation, northeastern Sichuan Basin, southwest China. The mechanism forming these reservoir dolomites is debatable, limiting the ability to characterize these reservoir successfully. Based on the investigation of the representative Dukouhe, Luojiazhai, and Puguang areas, this issue was addressed by examining the distribution, petrology, and geochemistry of the dolomites, the most comprehensive study to date was provided. Dolomitization occurred at a very early stage of diagenesis, as shown by the petrological features of the rock fabric. Vadose silt, which is composed primarily of dolomitic clasts, is found in the primary and secondary pores of the oolitic dolomite. This indicates that the overlying strata were subjected to dolomitization when the Feixianguan formation was located in the vadose zone. Therefore, it may be inferred that the dolomitization which occurred before the formation was exposed to meteoric conditions. The spatial distribution and geochemical characteristics of the dolomite indicate that dolomitization occurred as a result of seepage reflux. The degree of dolomitization decreases with increasing distance from the evaporative lagoon. Furthermore, the type and porosity of the dolomite vary in different zones of the upward-shoaling sequence, with the porosity gradually decreasing from the highest layer to the lowest layer. This reflects a close relationship between dolomitization and seawater evaporation during the formation of the dolomite. Geochemical analysis provided further evidence for the relationship between the dolomitization fluid and the coeval seawater. The 87Sr/86Sr and 813C isotopes, as well as the abundances of trace elements, Fe and Mn, indicate that seawater concentrated by evaporation acted as the dolomitization fluid. These results also show that dolomitization most likely occurred in a semi-closed diagenetic environment. Therefore, the main mechanism of oolitic dolomite formation is seepage reflux, which occurred at an early stage of diagenesis.
文摘For understanding the source and location mechanism of lode gold deposits hosted in metamorphic rocks in northeastern Hunan, the authors analyzed the REE (rare earth elements) in ores and their host rocks, metallogenic elements in host rocks near and distant from the ore bodies, and characteristics of ore controlling structures, and deduced their genetic implication. Their geochemical features of REE and metallogenic elements suggest that they are formed by mobilization of dispersed metallogenic materials in Lengjiaxi Group of Middle Proterozoic during deformation and metamorphism process, mainly in Wulingian period. From the attributes of ore controlling structures and regularity of location of gold metallization, it is concluded that the location of gold deposits is closely related to reverse shearing. Ore forming fluids are focused on the secondary faults and extension fractures of reverse shear zones of nearly EW strike by stress driven diffusion and seismic pumping.
文摘The Middle Triassic Ladinian-Upper Triassic Norian series in the Mesozoic-Cenozoic Ruo’ergai basin of Songpan area is characterized of large thick shallow marine-deep marine fine grained clastic.The strata are regionally unconformable between each adjacent two of the Middle-Late Triassic fine grained clastic,the Jurassic coal-containing clastic,the Cretaceous-Paleogene variegated coarse clastic。
文摘As the stress concentrated area of the Euro\|Asia and Indian plates collision, Tibet plateau has its special geological structure background.And its evolution has been drawing attentions of more and more geologists.The Sino\|French lithoscope group deployed 28 three\|component seismometers in 1998 from Gonghe to Yushu in Qinghai Province. These stations was distributed on most tectonic unit in Eastern Tibet, which are Eastern Qaidam Basin\|Gonghe Basin, Eastern Kunlun Fault\|Maqin Suture,Bayan Har\|Ganzi Terrane,Jinsha Suture and Qiangtang Block from north to south.According to 19 well\|recorded P wave events, after the data processing such as broading the frequence band,integration to get ground motions,then filtering and deconvolution, most stations’ data can achieve good receiver function with clear Ps conversions which show a step\|shaped Moho with southward dipping. The biggest Ps conversions occur 5～9 seconds after P arrival from north to south. Broad peak and its perturbations mean thicker sediments in Gonghe Basin and south of Jinsha Suture. And correspondent inversion shows there are two discontinuous positions where Kunlun Fault and Jinsha Suture are located. The crust thickness is about 55km in Gonghe Basin and nearby, deeper to 70km in Bayan Har Terrane, and 75～80km in the Qiangtang Block. A 20～40km deep low\|velocity zone can be traced along the profile although it is displaced by the faults. In Bayan Har Terrane some stations show a little eastward inclination of Moho due to comparing the receiver function from different back\|azimuth. A model is deduced that support both Qilian Plate and Qiangtang Block’s subduction beneath Bayan Terrane, and do uble\|crust and escape\|structure is therefore possible because of the stress st ate.
文摘亚中尺度过程是海洋学研究的前沿热点领域,从高分辨率资料中实现亚中尺度信号的快速提取对开展亚中尺度动力学研究具有重要意义。为此,根据亚中尺度过程的物理特性,提出一种基于深度学习的自动识别方法,构建了基于U-Net网络的海洋亚中尺度过程识别网络(submesoscale processes automatic identification network, SM-Net),该网络采用视觉几何组网络作为主干特征提取网络并引入改进的混合注意力模块以提升识别能力。基于高分辨率MITgcm (Massachusetts Institute of Technology general circulation model)模式数据,通过SM-Net准确识别出南海东北部全年的亚中尺度过程,并分类为冷涡、暖涡和锋面。南海东北部亚中尺度冷涡、暖涡和锋面均多发生于冬季,夏季的发生频率较低,但吕宋海峡的亚中尺度过程全年均较为活跃。除吕宋海峡外,亚中尺度冷涡夏季多发生于台湾岛西南海域、吕宋岛西南海域和吕宋岛沿岸,冬季多发生于南海北部陆坡陆架区;亚中尺度暖涡夏季多发生于吕宋岛沿岸,冬季在南海北部陆坡陆架区较为活跃;亚中尺度锋面的时空特征与冷涡相似,但黑潮流经区域的发生频率更高。亚中尺度过程罗斯贝数和动能的时空特征与发生频率具有较好的一致性,暖涡的动能、罗斯贝数和直径均弱于冷涡。上述识别方法在南海的成功运用,为应用SWOT (surface water and ocean topography)卫星数据研究亚中尺度过程提供了一定参考。
