The Oman Exotics: a key to the understanding of the Neotethyan geodynamic evolution     

Alain Pillevuit  Jean Marcoux  Gérard Stampfli  Aymon Baud 《Geodinamica Acta》2013,26(5):209-238

Abstract

The study of the exotic blocks of the Hawasina Nappes (Sultanate of Oman) leads to give apposit data that allow us to propose a new paleogeographic evolution of the Oman margin in time and space. A revised classification of exotic blocks into different paleogeographical units is presented. Two newly introduced stratigraphic groups, the Ramaq Group (Ordovician to Triassic) and the Al Buda’ah Group (upper Permian to Jurassic) are interpreted as tilted blocks related to the Oman continental margin. The Kawr Group (middle Triassic to Cretaceous) is redefined and interpreted as an atoll-type seamount. The paleogeography and paleoenvironments of these units are integrated into a new scheme of the Neotethyan rifting history. Brecciae and olistoliths of the Hawasina series are interpreted to have originated from tectonic movements affecting the Oman margin and the Neotethyan ocean floor. The breccias of late Permian age were generated by the extension processes affecting the margin, and by the creation of the Neotethyan oceanic floor. The breccias of mid-late Triassic age coincide in time with the collision of the Cimmerian continents with Eurasia. In constrast, the breccias of late Jurassic and Cretaceous age are interpreted as resulting to the creation of a new oceanic crust (Semail) off the Oman margin.  相似文献   

Characteristics of Crustal Movement in Longmenshan and Its Adjacent Region after Wenchuan Earthquake     

TANG wenqing  ZHANG Qingzhi  PAN Zhongxi  LI Jun  YANG Cheng 《《地质学报》英文版》2013,87(Z1):386-386

  相似文献   

勉县--略阳带大地构造属性之探讨   总被引：5，自引：1，他引：4  

冯益民  曹宣铎  张二朋 《地质论评》2004,50(3):295-303

本文从剖析勉略带南北两侧泥盆纪-石炭纪沉积入手,指出南北两侧同属于华南古生物地理区,在沉积相、沉积建造和沉积充填序列方面基本相同,都是以浅海相碳酸盐岩-碎屑岩沉积建造和海进型充填序列为特征.其次,对所谓的"勉略蛇绿岩带"提出质疑;岩石组合和时代配置都不支持该蛇绿岩带作为分割性大洋盆地的残余,何况它有限的空间展布同样不支持上述观点.第三,将勉略带同典型的缝合带进行比较,认为勉略带缺乏典型缝合带内部及其两侧地质体的空间配置关系,诸如沟弧盆体系,俯冲杂岩及前陆盆地等.况且,根据相关的地球化学及地球物理资料,勉略带在泥盆纪-三叠纪期间不存在分割性大洋盆地,在印支运动中也没有形成缝合带.因此,提出勉略带在泥盆纪-石炭纪曾经是一个裂谷,印支运动以来历经多期构造作用形成一条构造混杂带,在陆内造山过程中可能发生过大规模的大陆地壳消减.  相似文献   

岩土破损力学:结构块破损机制与二元介质模型     

刘恩龙 《岩土力学》2010,31(Z1):13-22

沈珠江等在总结岩土材料的基本特性、分析理论和研究方法的基础上,提出了岩土破损力学理论框架和二元介质模型概念。基于岩土二元介质模型思想,近年来在试验、理论和数值模拟方面对结构性岩土材料进行了详细研究。通过对棒状和棱柱状结构块试件的平面试验,探讨了结构性岩土材料的破损机制,并发现了在受荷过程中结构块逐渐破损并转化为软弱带二者共同抵抗外部作用,即验证了二元介质模型对结构性岩土材料力学抽象的正确性;扩展了岩土二元介质模型对岩土材料的脆性变化进行了模拟,并与结构性土和砂岩的三轴试验结果进行了验证;基于二元介质模型概念,发展了一种模拟岩土材料破损过程的细观数值方法,同时提出了适用于结构性岩土材料的强度准则。  相似文献   

基于系统评价的块体可靠度指标分析及应用     

申艳军  徐光黎  朱可俊 《岩土力学》2011,32(1):224-229

利用条件概率评价及系统工程理论,将关键块体作为块体系统一个重要组成部分,分析了关键块体可靠度指标评价办法,探讨了关键块体与次生关键块可靠度内在关系,由此类推,提出块体系统评价方法,推导出块体系统可靠度计算公式,实现对块体系统的失稳概率的评价计算。并选择一工程实例,对评价方法予以验证。结果表明：传统关键块体可靠度评价办法忽略块体间内在影响,结果偏向风险;而文中方法综合考虑块体之间影响,并建立了系统评价模型,对块体系统评价更接近实际情况,对块体系统理论的研究有一定借鉴意义。  相似文献   

A New Method of Surveying Underwater Parts of Self Elevating Drilling Platform     

Cong Zheyan Ji Liangying Senior Engineer  Bohai Engineering & Design Company  Shanghai Senior Engineer  Shanghai Shipyard  Shanghai 《中国海洋工程》1991,(1)

It is a new method of surveying leg spuds of self-elevating drilling platforms to lift them out of water with the help of additional middle guide blocks. Its main advantages in comparison with other methods normally used up to now are: less expensive, time saving, no need for specially designated water area, direct visual observation, good reliability and safety. The working principle has been presented with the example of two platforms "Bohai No. 8" and "Bohai No. 10", to which the method was used. Also a comprehensive comparison with other methods in technological and economical aspects is given in the paper.  相似文献   

华北地区地壳水平运动演化特征研究   总被引：13，自引：6，他引：7  

张跃刚  胡新康 《大地测量与地球动力学》2004,24(1):56-62

将华北地区划分为阴山-燕山、鄂尔多斯、山西、太行、冀鲁、胶辽6个块体，应用1995、1996、2001年GPS观测资料研究了这些块体的水平运动演化特征。结果显示出华北地区各块体的相对运动既有继承性也有差异性。华北各块体的总体水平运动趋势是向东漂移，但是个别块体，如鄂尔多斯块体，在1995～1996年期间出现了相对的西向运动。1995～1996年期间华北各块体的运动速率比1996～2001年期间的运动速率要大，特别是阴山-燕山块体。1995～1996年期间鄂尔多斯块体和相邻的山西块体表现为张性分离，阴山-燕山块体之间表现为左旋走滑，这一现象可能与1996～1999年期间发生在华北西北部的3个地震的孕震过程有关。进一步分析表明，加密的连续GPS观测可用于地震预报。  相似文献   

边缘撕裂--一种致裂致震机制   总被引：1，自引：1，他引：0  

王庆廷  蒋福珍 《大地测量与地球动力学》2002,22(4):97-100

明确提出两个板块或地块之间相互作用（主要是错动）中存在一种致裂致震机制－边缘撕裂，并以中国云南境内的红河断裂和美国加州的圣安德列斯两侧地块的边缘撕裂现象为例作了具体阐述。  相似文献   

The Deformation of Active Tectonic Blocks on the Chinese Mainland and Its Relationship with Seismic Activity     

Wang Hui 《中国地震研究》2004,18(1):54-66

Based on the hypothesis of the active tectonic blocks on the Chinese continent and its adjacent regions (both the method of the DDA on a spherical surface and the GPS survey results observed from 1991 to 2001 are used), the movements and deformations of each active tectonicblock are calculated. The calculation results show that although the movements and deformations of active tectonic-blocks in the eastern region and in the western region of China are different, active tectonic blocks in the same active tectonic block region are coherent.Then, the relative velocities of the active tectonic-blocks‘ boundary zones are calculated, and the relationship between current crustal motion and strong seismic activities is discussed. Earthquakes (Ms≥7.0) on the Chinese continent since 1988 all occurred on boundary zones of active tectonic blocks with high slipping speed.  相似文献   

油藏地球化学在沈家铺断块油田的应用     

尹伟  林壬子 《地球化学》2003,32(5):476-484

首先采用色谱、色谱-质谱等分析技术研究了本区枣Ⅴ油组原油地球化学特征及断块间油藏流体连通性，然后利用岩石热解(Rock-Eval)和薄层色谱-火焰离子检测技术(TLC—FID)，结合试油及测井资料，建立了枣Ⅴ油组油干水层划分的地球化学标准，研究了流体(原油)及其性质在纵向上和平面上的变化及分布规律。研究结果表明，枣Ⅴ油组原油为低成熟原油，其源岩形成于微咸水一半咸水湖相还原环境，主要由菌藻类有机质组成，但某些藻类可能是其源岩有机质的主要贡献者；枣Ⅴ油组断块间油藏流体不连通；纵向上，储层流体非均质性强，总体而言，随深度增加枣Ⅴ油组储层含油性逐渐变差，但原油性质逐渐变好。平面上，储层流体非均质性强，不同断块含油性不同，同一断块不同部位含油性不同；不同断块原油性质不同，总体而言，从NE到SW，枣Ⅴ油组的原油性质逐渐变好。  相似文献