Comparison of the Typical Metallogenic Systems in the North Slope of the Tongbai-East Qinling Mountains and its Geologic Implications     

ZHANG Jing  CHEN Yanjing  QI Jinping  GE Jun State Key Laboratory of Geological Process  Mineral Resources  China University of Geosciences  Beijing  China Key Laboratory of Metallogenic Dynamics  Guangzhou Institute of Geochemistry  the Chinese Academy of Sciences  Guangzhou  China 《《地质学报》英文版》2009,83(2)

The Tongbai-East Qinling Mountains,an important part of the Central orogenic belt,is one of the most important metallogenic belts in China and contains lots of orogenic-type and VMS-type (Volcanogenic Massive Sulfide type)metallogenic systems.The Dahe and Shuidongling VMS-type Cu-Zn deposits,located in the Erlangping Group in Tongbai and East Qinling Mountains,respectively, show similar geological and geochemical features.The Huoshenmiao Formation in the East Qinling region and the Liushanyan Formation i...  相似文献   

Revision of the Clam Shrimp Genus Magumbonia from the Upper Jurassic of the Luanping Basin,Hebei,Northern China     

Peter BENGTSON  Helmut WILLEMS  Hiramichi HIRANO 《《地质学报》英文版》2009,83(1)

The diverse clam shrimp Nestoria-Keratestheria fauna is widely distributed in the Dabeigou Formation in northern Hebei and eastern Inner Mongolia of China.Its important component genus Magumbonia from the Dabeigou Formation in the Luanping Basin,northern Hebei,China,is revised on the basis of a scanning electron microscope (SEM) examination of the type species M.jingshangensis Wang,1984,which revealed morphological features not recognized previously.These include coarse reticulation on the umbo and promi...  相似文献   

龙卷风的漏斗结构理论   总被引：4，自引：1，他引：3       下载免费PDF全文

刘式适  付遵涛  刘式达  许焕斌  辛国君  梁福明 《地球物理学报》2004,47(6):959-963

龙卷风是大气中风速和垂直速度极大的小尺度系统.本文用气压梯度力、惯性离心力、黏性力三力平衡的柱坐标(r,θ,z)下的大气动力和热力学方程组,求龙卷风的三维速度场(vr,vθ,vz),从理论上绘制出龙卷风的三维漏斗型结构.充分说明龙卷风由涡旋流和急流这两种流叠加而成,涡旋流是由惯性离心力造成的,急流是由水平辐合辐散而引起的强对流.龙卷风是在极端不稳定的大气层结中形成的.  相似文献   

利用GPS监测电离层不均匀结构探讨   总被引：7，自引：0，他引：7       下载免费PDF全文

朱文耀  章红平  黄珹  金双根 《地球物理学报》2004,47(6):941-948

利用上海地区GPS综合应用网提供的高时空分辨率的双频GPS观测资料,研究了该区域内一电离层不均匀体的产生、消亡过程.首先,采用Kalman滤波的方法改善双频伪距之差的观测精度,并利用参数估计的方法计算该时段内相应的硬件延迟.再根据电离层单层模型,利用GPS双频观测量、测站位置和GPS精密星历,求出GPS信号穿刺点的坐标和垂直方向电离层的电子含量;然后内插并获取其等值线图.等值线图随时间的变化表明,受等离子体湍流的影响,2003年9月8日北京时间9时40分左右在38°N、118°E左右产生了一电离层不均匀体,其尺度大约在50km左右,生存时间大约为5min.受地球重力场和高空风场的影响,该不均匀体向东北方向扩散.然后,利用大气扩散模型,按扩散方程计算分析了该不均匀体可能发生的电离层层区.理论计算表明,该不均匀体发生在电离层扩展F区,高度在350km左右.  相似文献   

东昆仑西端布喀达坂峰地区二叠纪孢粉型化石的发现     

宋泰钟  尹磊明  欧阳舒  王秉璋  王瑾  叶占福  宋生春 《地层学杂志》2004,28(2):142-147

在东昆仑西端布喀达坂峰地区二叠纪地层中首次发现陆相孢粉与海相疑源类化石一起保存的孢粉—疑源类化石组合。经对两个样品较为丰富的孢粉型化石研究后发现,上部组合以裸子植物花粉占优势,双囊无肋花粉最多,可与塔里木盆地的卡伦达尔组的孢粉组合做粗略的比较,但组合中出现了时代偏晚的Ephedripites及Taeniae-sporites,因此,研究区马尔争组中段复理石地层的时代当为中二叠世—晚二叠世。  相似文献   

华夏植物群起源中心的研究     

孙克勤  邓胜徽 《地质论评》2004,50(4):337-342

要贺兰山一带石炭纪、二叠纪地层发育,晚石炭世早期至二叠纪的地层连续出露,其中富含植物化石,特别是晚石炭世纳缪尔B—C期的红土洼组含丰富的早期华夏植物群分子。笔者多年来的研究表明,在此连续剖面上,植物化石反映出植物群的演化趋势颇为明显,构成石炭纪和二叠纪植物群较为连续的演化序列。植物群中含有大量的华夏型分子,属典型的华夏植物群。内蒙古阿拉善左旗呼鲁斯太剖面晚石炭世早期红土洼组是迄今为止含华夏植物群的最有代表性层位,所含植物化石是目前已记载的最为丰富的晚石炭世早期华夏型植物组合,因此笔者认为贺兰山一带可视为华夏植物群的起源中心。  相似文献   

震后快速钻探:历史、现状与未来     

Emily E.Brodsky  Kuo-Fong Ma  Jim Mori  Demian M.Saffer  李丽 《国际地震动态》2010,(4):9-18

大地震发生后立即在断层带上进行钻探可以帮助我们获取更多的地震信息,尤其是可获得决定断层动态破裂的摩擦水平和强度,观测断层的愈合过程及可能触发余震的应力变化,并可获取控制破裂过程的重要的物理和化学属性。在2008年11月由国际大陆科学钻探项目（ICDP）和南加州地震中心（SCEC）联合在日本东京举办的为期3天的“震后快速钻探：历史、现状与未来”研讨会上,  相似文献   

地震预报实验场:科学问题与科学目标     

"地震预报发展规划"工作组 《中国地震》2010,26(1)

本文简要回顾了以往地震预报实验场的经验教训,讨论了新一代地震预报实验场的实施策略。汲取汶川地震的经验启示,本文提出"地震博弈"策略,即考虑中长期地震预测的可用性与不确定性,在监测与实验系统设计中考虑地震活动和地震构造相依的区域模型。对于特定的活动断裂或活动地块边界带的潜在强震段落,设置适应多种孕震模型的"想定地震破裂",针对地震孕育的"想定模式"设计观测项目和监测系统。这一系统以地震成因和孕震模型的有效约束、"预期"前兆的有效监测、预测/预报效能的有效检验为导向。从技术角度,本文提出将地震预报实验场作为一个"大科学工程",强调复杂的多层次、多组分技术系统性能的稳健性,以及为确保与地震有效的"近距离接触"的系统可持续性。  相似文献   

Deep sea in situ excess pore pressure and sediment deformation off NW Sumatra and its relation with the December 26, 2004 Great Sumatra-Andaman Earthquake   总被引：1，自引：0，他引：1  

Nabil Sultan  Antonio Cattaneo  Jean-Claude Sibuet  Jean-Luc Schneider  the Sumatra Aftershocks team 《International Journal of Earth Sciences》2009,98(4):823-837

The swath bathymetric data acquired during the “Sumatra Aftershocks” cruise from the Sunda trench in the Indian Ocean to the north of the Sumatra Island imaged several scars and deposits. In situ pore pressure measurements using the Ifremer piezometer and coring demonstrate that high excess pore pressure and sediment deformation was generated by a recent event in the scar of the slope failure zone identified by J.T. Henstock and co-authors. This excess pore pressure is localized in the upper sedimentary layers and is not related to an interplate subduction process. Numerical simulations of the hydrological system that take into account the hydro-mechanical properties of the upper sediment layer show that the excess pore pressure and sediment deformations could be generated at the time of the December 26, 2004 Great Sumatra Earthquake. The Sumatra Aftershocks team: J.-C. Sibuet, S. Singh, R. Apprioual, N.C. Aryanto, J. Begot, A. Cattaneo, A.P.S. Chauchan, R. Creach, J. Crozon, A. Domzig, N. Falleau, D. Graindorge, F. Harmegnies, Y. Haryadi, F. Klingelhoffer, S.K. Kolluru, J.-Y. Landuré, C. Le Lann, J. Malod, A. Normand, G. Oggian, C. Rangin, D. Restunin Galih, J.-L. Schneider, N. Sultan, M. Taufik, M. Umber and H. Yamaguchi.  相似文献   

Effects of reduced salt concentrations on plant communities in the River Werra (Germany)     

Eckhard Coring  Jürgen Bäthe 《Limnologica》2011,41(2):134-142

The reduction and equalization of the salt concentrations in the River Werra have resulted in a gradual recovery of the aquatic flora. Spatial high-resolution macrophyte mappings document the spread of the aquatic vascular plants in the middle and lower River Werra. Simultaneously, the plankton blooms have declined. Changes in the composition of the algal communities including diatoms also indicated lower salinity. In addition to the salinity, high nutrient concentrations, waste water discharges and structural degradation are important stressors in the River Werra as shown by e.g. low species richness of vascular plants and the common occurrence of pollution tolerant diatoms. From the existing data it is clear that an encompassing improvement of the ecological conditions in the River Werra can only be achieved by further restoration measures considering all stressors.  相似文献