Crustal structure of northeastern Tibetan plateau and Ordos block:Waveform interpretation of the Maqen-Jingbian seismic refraction profile     

Fuyun Wang Hong Shang  Xiankang Zhang Geophysical Exploration Center  China Earthquake Administration  Zhengzhou  China 《地震学报(英文版)》2009,(4):365-371

The Maqen-Jingbian wide-angle seismic reflection and refraction experiment was carried out in 1998,which aims at determining detailed structure in the crust and top of the upper mantle and understanding structural relation between the northeastern Tibetan plateau and the Ordos block. The 1-D crustal models inferred by waveform inversion show strong variations in crustal structure,which can be classified into four different types:1 an Ordos platform with the Proterozoic crust and two high-velocity layers in ...  相似文献   

Deep seismic sounding data reveal the crustal structures beneath Zoigê basin and its surrounding folded orogenic belts     

JIA ShiXu  ZHANG XianKang  ZHAO JinRen  WANG FuYun  ZHANG ChengKe  XU ZhaoFan  PAN JiShun  LIU Zhi  PAN SuZhen & SUN GuoWei Geophysical Exploration Center  China Earthquake Administration  Zhengzhou  China 《中国科学:地球科学(英文版)》2010,(2)

Songpan-Garze massif is located at the turning position of tectonics from the nearly west-east direction to the nearly north-south direction in the northeastern margin of Tibetan Plateau,with Zoigê basin in the centre of the massif.In this paper,we build a crustal structure model of Zoigê basin and its surrounding folded orogenic belts using the deep seismic sounding data in this region.We also discuss structures and properties of the basement in Zoigê basin,tectonic relations between Zoigê upland basin and its surrounding folded orogenic belts,crustal deformation and thickening in the northeastern margin of Tibetan Plateau,and decoupling and relaxing processes in the crust.The results indicate that a special "Mesozoic basement" is formed of Triassic rocks with high density (2.65-2.75 g/cm3) and high velocity (5.6 km/s) in Zoigê basin.Songpan-Garze tectonic massif was transformed into two types of tectonic units with different crustal structures,i.e.,relatively stable Zoigê upland basin and active folded orogenic belts around the basin,in the course of the crustal material of Tibetan Plateau flowing eastward and obstructed by surrounding stable blocks.The thickening of the crust in the northeastern margin of Tibetan Plateau mainly occurred in the mid and lower crust,and the structure characterized by low velocities and multiple reflectors obviously appears in the folded orogenic belts around Zoigê basin.It implies that the mid and lower crust underwent a strong tectonic deformation in the folded orogenic areas.The thickness of the crust is about 50 km in Zoigê basin and the folded orogenic belts at the both southern and northern sides of Zoigê basin.The "Mountain root" cannot be identified.It is inferred that during the later orogenic period the eastwards flowing deep materials moved clockwise along the relatively relaxing southern side around the eastern tectonic knot under the obstructing of surrounding rigid massifs,and it resulted in the strong stretching action of the folded orogenic belts around Zoigê basin.  相似文献   

Seismic Features of the Crust-Upper Mantle Beneath Karamay-Kuqa, Xinjiang   总被引：2，自引：0，他引：2  

JIANG Mei  XUE Guangqi  SU Heping  QIAN Hui  WEI Suhua  DONG Yingjun Institute of Mineral Resources  CAGS  Beijing  China E. KISSLING ETH-Hongebeg Institute for Geophysical CH- ZURICH  Switzeland G. POUPINET LGIT-IRIGM  Univercite Joseph F 《Continental Dynamics》2000,(1)

1. IntoductionSponsored by the National 305 Program, China, a teleseismic experiment was performed jointly by the Chinese Academy of Geological Sciences and the French Scientific Research Center in Tian Shan area from June 1997 to February 1998. The array was mostly deployed along the main road, starting from Karamay in the north to Kuqa in the south. Geologically, the 700 km-long profile covers the Junggar basin, the Tian Shan Mts., the Bo-A Fault and the Korla Fault, ending in nort…  相似文献   

Geoelectrical Structure of the Crust and Upper Mantle in the Qinling and Adjacent Regions   总被引：2，自引：0，他引：2  

LI Li  JIN Guoyuan  YANG Piyuan  LIU Yuhua Institute of Geophysical  Geochemical Exploration  Ministry of Geology  Mineral Resources  Langfang  Hebei  China ZHUO Xianjun Department of Petroleum Exploration of Zhejiang Province  Yuha 《Continental Dynamics》1999,(1)

１．Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｔｈｅｄａｔａｏｆｔｈｉｓｓｔｕｄｙａｒｅｃｏｌｌｅｃｔｅｄｆｒｏｍ２１６ｍａｇｎｅｔｏｔｅｌｌｕｒｉｃｓｏｕｎｄｉｎｇｐｏｉｎｔｓｏｎｔｈｅｆｏｌｌｏｗｉｎｇｐｒｏｆｉｌｅｓａｃｒｏｓｓｔｈｅＱｉｎｌｉｎｇｏｒｏｇｅｎ,ｔｈｅＹｅｘｉａｎ（ｉｎＨｅｎａｎＰｒｏｖｉｎｃｅ）－Ｎａｎｚｈａｎｇ（ｉｎＨｕｂｅｉＰｒｏｖｉｎｃｅ）Ｐｒｏｆｉｌｅ（Ｌｉｅｔａｌ．,１９９８）,ｔｈｅＬｕｏｙａｎｇ（ｉｎＨｅｎａｎＰｒｏｖｉｎｃｅ）－Ｓｈｉｙａｎ（ｉｎＨｕｂｅｉＰｒｏｖｉｎ…  相似文献   

湘南骑田岭地区锡矿富集的磁梯度矢量结构研究     

郭友钊 《地质学报》2006,80(10):1553-1557

湖南骑田岭岩体南部地区已发现的单脉锡矿储量大于1万t的矿体有9条,其中19号脉储量约为25万t,其他8条储量为18万t,可见各脉的锡矿富集情况极为悬殊。本文通过对航磁异常的幅值和梯度矢量结构的研究,发现特别富集的19号脉位于航磁ΔT异常以及上延1000m磁异常矢量梯度的交汇部位和上延2000m磁异常矢量梯度的汇集部位,而其他8条矿体则没有此特征;19号锡矿体之所以特别富集,可能是由于从浅层到深部的成矿流体均运移汇聚而富集,而其他8条矿体则可能只是浅部成矿流体的局部富集。同时,根据与19号脉相似的磁异常矢量梯度的结构,本文指出了3个异常区可能是寻找大型矿脉的靶区。  相似文献   

Quantitative Expression of Heat Flow versus Tectonic Deformation in the China Continent： The Effects of Plastic-Flow Network and Stable Block   总被引：1，自引：0，他引：1  

WANG Sheng-zu Institute of Geology  State Key Laboratory of Earthquake Dynamics  China Earthquake Administration  Beijing 《《地质学报》英文版》2006,80(1):97-109

1 Introduction It has been understood in the study of terrestrial heat flow that the distribution of heat flow in the interior of continent is influenced by a large number of factors, involving heat sources (e.g. mantle heat flow, heat production of radioactive elements in the crust, magmatic activity, and heat production of tectonic deformation), heat transfercondition (e.g. thermal conductivity and thickness of media), groundwater circulation, etc. On the background of these factors it is pa…  相似文献   

成矿元素的气相迁移与实验研究   总被引：2，自引：0，他引：2       下载免费PDF全文

张生  熊小林  T.M.Seward 《地学前缘》2009,16(1):68

越来越多的野外观测和实验数据表明,气相对成矿元素的迁移和富集具有不可忽视的作用。由高温火山气体形成的升华壳和凝结水中富集多种岩浆组分和成矿金属;中低温的地热田水蒸气中也检测到成矿元素;某些斑岩型铜-金矿床的富气体包裹体比共存的盐水包裹体更富集Cu和Au。金属呈简单氯化物或氟化物、硫化物、含氧酸及原子迁移的理论假设低估了400℃以下气体搬运成矿金属的能力,而必须考虑溶剂化作用(水合作用),有关银、金、铜、锡、钼、钨在水热气相中的溶解度实验证实了这一点,基于实验数据的热力学模拟计算表明,水热气相可运移足够的成矿金属以形成具有经济价值的浅成热液型和斑岩型矿床。此外,实验也证实砷和硼从液相分配至气相中也与水合作用有关,其气液相间的分配系数随温度和水蒸气的压力增大而增强。无疑地,成矿金属被水热气相搬运的理论对理解金属矿床的形成机理和发展诸如深穿透地球化学的地球气找矿方法具有重要意义。  相似文献   

从滇黔桂“金三角”区域地层地球化学演化特征探讨卡林型金矿的物质来源   总被引：3，自引：0，他引：3       下载免费PDF全文

周余国  刘继顺  王作华  欧阳玉飞  高启芝  刘德利  黄元有 《地学前缘》2009,16(2):199

选用滇黔桂地区东经103°～110°,北纬22°～26°,面积约20万km2,34幅1∶20万水系沉积物统计结果资料,全面系统地探讨本区及其邻近区域地层地球化学特征及其与成矿的关系。结果表明:(1)与华南地区相比,本区存在Sb、As、Au、Hg等低温元素矿集区的地球化学块体,金具有深源性,而砷、锑、汞则是区域性的高背景,本区金与砷、锑、汞的相伴,既有必然性,又有偶然性;(2)与基性岩浆活动有关的亲基性场元素、氧化物、矿化剂高背景的形成,是本区右江裂谷带、富宁—关岭南北向断裂带、文山—富宁逆冲推覆构造带,特别是峨眉地幔柱所产生的基性岩浆喷溢及火山碎屑浊流沉积的客观地球化学反映;(3)黔西南地区二叠纪峨眉山玄武岩喷发导致二叠系和三叠系金及大量亲基性场元素的突变,右江裂谷活动至少始于寒武纪,随着时间的推移,由桂西往黔西南逐渐裂开;(4)滇黔桂"金三角"地区卡林型金矿的物源与裂谷、特提斯和区域性深大断裂和峨眉地幔柱长期活动相伴的基性火成岩及火山碎屑浊流沉积有关。  相似文献   

Migration of Depocenters and Accumulation Centers and its Indication of Subsidence Centers in the Mesozoic Ordos Basin     

ZHAO Junfeng  LIU Chiyang  WANG Xiaomei  ZHANG Can Chemistry Postdoctoral Program of Northwest University  Xi'an  Shaanxi  China State Key Laboratory of Continental Dynamics  Northwest University  China 《《地质学报》英文版》2009,83(2)

Based on the integrated study of structure attributions and characteristics of the original basin in combination with lithology and lithofacies,sedimentary provenance analysis and thickness distribution of the Mesozoic Ordos Basin,it is demonstrated that the depocenters migrated counterclockwise from southeast to the north and then to the southwest from the Middle-Late Triassic to the Early Cretaceous.There were no unified and larger-scale accumulation centers except several small isolated accumulation c...  相似文献   

中国大陆科学钻探工程主孔3000～3500 m花岗质片麻岩地球化学性质及其成因机制   总被引：1，自引：0，他引：1  

周开富刘福来  许志琴李天福杨经绥  薛怀民叶建国 《地质学报》2006,80(12):1851-1866

中国大陆科学钻探工程主孔(CCSD-MH)3000~3500m深度范围内的岩心揭示的主要岩石类型以正、副片麻岩为主,夹少量的榴辉岩、片岩及斜长角闪岩等。正片麻岩可进一步划分为钾长花岗质片麻岩和二长花岗质片麻岩。地球化学研究表明,花岗质片麻岩的SiO2含量普遍高,为73.56%~79.01%,Al2O3含量为10.49%~13.75%;TiO2、Fe2O3、FeO、MnO和MgO的含量明显偏低,其中Fe2O3为0.26%~2.56%,FeO为0.09%~1.13%,MgO为0.01%~0.63%;岩石明显富含Na2O、K2O,强烈贫钙,Na2O K2O的含量为6.20%~9.15%,K2O的含量为1.26%~5.67%,CaO的含量为0.08%~1.59%。花岗质片麻岩在洋脊玄武岩标准化蛛网图上都表现出强烈富集大离子亲石元素(K、Rb、Th)的特点,高场强元素Ti、Ta和Nb表现为明显的负异常,而Hf和Zr则为明显正异常。3000~3500m花岗质片麻岩的原岩具A型花岗岩的特征,形成于大陆裂谷环境,记录了Rodinia超大陆裂解时苏鲁地区的花岗岩浆事件,表明新元古代晚期扬子板块北缘的构造属性为大陆裂谷环境。  相似文献