http://www.sciencedirect.com/science/article/pii/S1674987114000711   总被引：1，自引：0，他引：1  

Ping Shen  Hongdi Pan  Yuanchao Shen  Yuhong Yan  Shihua Zhong 《地学前缘(英文版)》2015,6(2):175-190

The West Junggar region,located in the loci of the Central Asian Orogenic Belt,is a highly endowed metallogenic province with >100 tonnes Au,>0.7 Mt Cu,>0.3 Mt Mo,and >2.3 Mt chromite as well as significant amounts of Be and U.The West Junggar region has three metallogenic belts distributed systematically from north to south:(1) late Paleozoic Saur Au-Cu belt;(2) early Paleozoic XiemisitaiSharburt Be-U-Cu-Zn belt;(3) late Paleozoic Barluk-Kelamay Au-Cu-Mo-Cr belt.These belts host a number of deposits belonging to at least eight economically important styles,including epithermal Au,granite-related Be-U,volcanogenic massive sulfide(VMS) Cu-Zn,podiform chromite,porphyry Cu,hydrothermal quartz vein Au,porphyry-greisen Mo(-W),and orogenic Au.These deposit styles are associated with the tectonics prevalent during their formation.Five tectonic-mineralized epochs can be recognized:(1) Ordovician subduction-related VMS Cu-Zn deposit;(2) Devonian ophiolite-related podiform chromite deposit;(3) early Carboniferous subduction-related epithermal Au and porphyry Cu deposits;(4) late Carboniferous subduction-related granite-related Be-U,porphyry Cu,and hydrothermal quartz vein Au deposits;and(5) late Carboniferous to early Permian subduction-related porphyry-greisen Mo(-W) and orogenic Au deposits.  相似文献   

Paleozoic convergence processes in the southwestern Central Asian Orogenic Belt:Insights from U–Pb dating of detrital zircons from West Junggar,northwestern China     

Pan Zhang  Guocan Wang  Tianyi Shen  Ali Polat  Chengyu Zhu 《地学前缘(英文版)》2021,12(2):531-548

The West Junggar orogen,located in the southwestern Central Asian Orogenic Belt(CAOB),preserves an abundant record of tectonic processes associated with the evolution of the Junggar Ocean.In this study,we use detrital zircon U–Pb age data from Ordovician to Carboniferous sandstones in the southern and central West Junggar domains,complemented by literature data,to better constrain the tectonic evolution of the southwestern CAOB.The Kekeshayi,Qiargaye,and Laba formations in the southern West Junggar domain were deposited during the Darriwilian-Sandbian,Katian-Aeronian,and Homerian-Emsian,respectively.Detrital zircon provenances of these formations display a marked shift from the southern West Junggar domain to the Paleo-Kazakhstan Continent(PKC).This suggests that the southern West Junggar intra-oceanic arc might have gradually accreted to the northern margin of the PKC prior to the Emsian,which has significantly contributed to the lateral growth of the PKC.The Carboniferous strata,Xibeikulasi,Baogutu,and Tailegula formations,in the central West Junggar domain represent a coherent sequence of volcaniclastic turbidites and were deposited in a progressively shrinking remnant oceanic basin during the Visean to Moscovian.They contain unimodal detrital zircon distributions and are derived from the local and coeval magmatic rocks in the central West Junggar domain.We propose that the final closure of the Junggar Ocean likely occurred in the end of the Late Carboniferous in response to regional amalgamation events in the southwestern CAOB,which marks the final assembly of the Kazakhstan Orocline.The central and southern West Junggar domains underwent individual evolution in the Paleozoic,and were recombined by the significant intra-continental reworking along the large-scale strike-slip faults.  相似文献   

Calculation of groundwater head distribution with a close barrier during excavation dewatering in confined aquifer     

Hai-Min Lyu  Shui-Long Shen  Yong-Xia Wu  An-Nan Zhou 《地学前缘(英文版)》2021,12(2):791-803

When pumping is conducted in confined aquifer inside excavation pit(waterproof curtain),the direction of the groundwater seepage outside the excavation changes from horizontal to vertical owing to the existence of the curtain barrier.There is no analytical calculation method for the groundwater head distribution induced by dewatering inside excavation.This paper first analyses the mechanism of the blocking effects from a close barrier in confined aquifer.Then,a simple equation based on analytical solution is proposed to calculate groundwater heads inside and outside of the excavation pit with waterproof curtain(hereafter refer to close barrier)in a confined aquifer.The distribution of groundwater head is derived according to two conditions:(i)pumping with a constant water head,and(ii)pumping with a constant flow rate.The proposed calculation equation is verified by both numerical simulation and experimental results.The comparisons demonstrate that the proposed model can be applied in engineering practice of excavation.  相似文献   

粤西水东弧形海岸海滩剖面的地貌状态   总被引：7，自引：0，他引：7  

陈子Shen  李春初 《热带海洋》1993,12(2):61-68

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粤西水东湾现代沉积环境特征与泥沙搬运路径   总被引：3，自引：0，他引：3  

陈子Shen 《热带海洋》1996,15(3):6-13

对粤西水东湾沉积地貌单元的现代沉积物分布特征分析与泥沙净搬运矢量计算表明，滨面斜坡沉积物主要由砂粒吸物质组成，粒级参数Ｍｄ，ＱＤ和ＳＫ具有从海向岸，自东向西变化的总趋势，泥沙净搬运趋势以向岸和西北为主，落潮三角洲沉积物较基邻近滨面斜坡有所粗化，分选从中部向西侧变泥沙在落潮流与波浪驱动下沿落潮三角洲边缘向西运动，口门内潮汐通道深槽泥沙净驼趋势指向湖，湖区的沉积物为泥质为主，分选中等至差，并形成绕涨潮  相似文献   

碎波带和海滩地貌动力变化性综述     

Wrig.  LD 陈子Shen 《南海研究与开发》1993,(2):65-72

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A new pterodactyloid pterosaur from the Early Cretaceous of the western part of Liaoning Province, northeastern China     

Lü Junchang  Liu Cunyu  Pan Lijun  Shen Caizhi 《《地质学报》英文版》2016,90(3):777-782

Pangupterus liui gen. et sp. nov. from the Jiufotang Formation of Sihedang, Lingyuan City, Liaoning Province is erected based on a nearly complete lower jaw. It is characterized by having a total of 36 slender curved teeth with sharp tips, forming a distinct fish-grabbing mechanism; the teeth are well-spaced and are circular in section; the length ratio of the mandibular symphysis to the whole jaw is 20%; and the ratio of the tooth root width to tooth length is 12%. Toothed pterosaurs make up about 56.3% of the pterosaur assemblage from the Jiufotang Formation, which indicates that toothed forms played a key role in the ecosystem.  相似文献   

Progress and future prospects of decadal prediction and data assimilation:A review          下载免费PDF全文

Wen Zhou  Jinxiao Li  Zixiang Yan  Zili Shen  Bo Wu  Bin Wang  Ronghua Zhang  Zhijin Li 《大气和海洋科学快报》2024,(1):55-64

年代际预测,也称为“近期气候预测”,旨在预测未来1-10年内的气候变化,是气候预测和气候变化研究领域的一个新关注点.它位于季节至年际预测和长期气候变化预测之间,结合了初值问题和外部强迫问题的两个方面.年代际预测的核心技术在于用于模式初始化的同化方法的准确性和效率,其目标是为模式提供准确的初始条件,其中包含观测到的气候系统内部变率.年代际预测的初始化通常涉及在耦合框架内同化海洋观测,其中观测到的信号通过耦合过程传递到其他分量,如大气和海冰.然而,最近的研究越来越关注在海洋-大气耦合模式中探索耦合数据同化(CDA),有人认为CDA有潜力显著提高年代际预测技巧.本文综合评述了该领域的三个方面的研究现状:初始化方法,年代际气候预测的可预测性和预测技巧,以及年代际预测的未来发展和挑战.  相似文献   

Research on Pulsar Time Steered Atomic Time Algorithm Based on DPLL     

Ze-Hao Zheng  Yang Liu  Dan Shen  Fan Feng  Jiu-Long Liu  Yue-Xin Ma  Xiang-Wei Zhu 《天文和天体物理学研究(英文版)》2024,(3):239-250

In today’s society, there is a wide demand for high-precision and high-stability time service in the fields of electric power, communication, transportation and finance. At present, the time standard in various countries is mainly based on atomic clocks, but the frequency drift of atomic clocks will affect the long-term stability performance.Compared with atomic clocks, millisecond pulsars have better long-term stability and can complement with the excellent short-term stability of atomic clocks...  相似文献   

Characteristics and generation mechanism of turbidity maximum in the Changjiang Estuary     

Pan Ding''an  Shen Huanting  Mao Zhichang  Liu Xincheng 《海洋学报(英文版)》2000,19(1):47-57

INTRODUCTIONItiswellknownthattheregenerallyexistsahigherconcentrationsedimentzoneinrivermouththanthatinthe'upperandlowerones,whichiscalledturbiditymaximum(TM).ButnomoreintensiveresearchonthisphenomenonhadbeenconductedforalongtimesinceitwasfoundinFrenchGirondeEstuaryin1938.Itwasnotuntilthe1950swhenitattractedresearchersallovertheworldandwasregardedasacommonphenomenoninanestuary.Itplayedanimportantroleinestuarinesedimentationandenvironment.Sincethe1960s,lotsofstudiesonTMintheChangjiangE…  相似文献