STRUCTURAL GEOLOGY     

《Abstract of Chinese Geological Literature》2014,(3)

正20141283 Bai Daoyuan(Hunan Institute of Geological Survey,Changsha 410016,China);Zhong Xiang Nature,Origin and Tectonic Setting of Jinzhou Basin in the South Segment of Xuefeng Orogen(Geology in China,ISSN1000-3657,CN11-1167/P,40(4),2013,p.1079-1091,10 illus.,47 refs.)Key words:foreland basins,strike-slip faults,Hunan Province  相似文献   

GEOPHYSICAL EXPLORATION     

《Abstract of Chinese Geological Literature》2014,(2)

正20141074Bao Xijie(Research Institute of Exploration and Development,Daqing Oilfield Company,PetroChina,Daqing 163712,China)Gather Optimal Processing and Application Effect of Prestack AVA Instantaneous Inversion  相似文献   

Influence of dissolution/reprecipitation reactions on metamorphic greenschist to amphibolite facies mica 40Ar/39Ar ages in the Longmen Shan (eastern Tibet)          下载免费PDF全文

Laura Airaghi  Clare J. Warren  Julia de Sigoyer  Pierre Lanari  Valérie Magnin 《Journal of Metamorphic Geology》2018,36(7):933-958

Linking ages to metamorphic stages in rocks that have experienced low‐ to medium‐grade metamorphism can be particularly tricky due to the rarity of index minerals and the preservation of mineral or compositional relicts. The timing of metamorphism and the Mesozoic exhumation of the metasedimentary units and crystalline basement that form the internal part of the Longmen Shan (eastern Tibet, Sichuan, China), are, for these reasons, still largely unconstrained, but crucial for understanding the regional tectonic evolution of eastern Tibet. In situ core‐rim ⁴⁰Ar/³⁹Ar biotite and U–Th/Pb allanite data show that amphibolite facies conditions (~10–11 kbar, 530°C to 6–7 kbar, 580°C) were reached at 210–180 Ma and that biotite records crystallization, rather than cooling, ages. These conditions are mainly recorded in the metasedimentary cover. The ⁴⁰Ar/³⁹Ar ages obtained from matrix muscovite that partially re‐equilibrated during the post peak‐P metamorphic history comprise a mixture of ages between that of early prograde muscovite relicts and the timing of late muscovite recrystallization at c. 140–120 Ma. This event marks a previously poorly documented greenschist facies metamorphic overprint. This latest stage is also recorded in the crystalline basement, and defines the timing of the greenschist overprint (7 ± 1 kbar, 370 ± 35°C). Numerical models of Ar diffusion show that the difference between ⁴⁰Ar/³⁹Ar biotite and muscovite ages cannot be explained by a slow and protracted cooling in an open system. The model and petrological results rather suggest that biotite and muscovite experienced different Ar retention and resetting histories. The Ar record in mica of the studied low‐ to medium‐grade rocks seems to be mainly controlled by dissolution–reprecipitation processes rather than by diffusive loss, and by different microstructural positions in the sample. Together, our data show that the metasedimentary cover was thickened and cooled independently from the basement prior to c. 140 Ma (with a relatively fast cooling at 4.5 ± 0.5°C/Ma between 185 and 140 Ma). Since the Lower Cretaceous, the metasedimentary cover and the crystalline basement experienced a coherent history during which both were partially exhumed. The Mesozoic history of the Eastern border of the Tibetan plateau is therefore complex and polyphase, and the basement was actively involved at least since the Early Cretaceous, changing our perspective on the contribution of the Cenozoic geology.  相似文献   

黑龙江依兰地区蓝片岩相变质作用及其演化   总被引：2，自引：2，他引：0  

韩晓萌  郑常青  徐学纯  韩玉宝  徐久磊 《岩石学报》2018,34(4):1139-1153

依兰地区蓝片岩作为黑龙江杂岩的重要组成部分,其变质作用演化问题一直存在较大争议。本文通过对依兰地区蓝片岩的岩相学及矿物微区化学成分的研究,并运用PERPLE_X软件,在Na_2O-CaO-K_2O-MnO-FeO-MgO-Al_2O_3-SiO_2-H_2O-TiO_2-O(Fe_2O_3)(NCKMnFMASHTO)体系下对石榴石冻蓝闪石片岩(g-brs-wnc-act-phn-chl-ep-ab-stlp)、绿泥绿帘蓝闪石片岩(gl-brs-wnc-act-chl-ep-stlp)和白云母蓝闪石片岩(gl-wnc-phn-ab-ep-chl-sph)进行了相平衡模拟,并分别获得了500~525℃/1.14~1.2GPa、480℃/1.4GPa、450~500℃/0.95~1.2GPa峰期变质作用的温压条件,其峰期变质级别都达到了绿帘-蓝片岩相。结合前人发表的地球化学和年代学数据,建立了蓝片岩相岩石的顺时针变质演化P-T轨迹。研究区蓝片岩的形成标志着新生洋壳的俯冲作用,同时代表古亚洲洋构造域的结束和环太平洋构造域的开始。相平衡模拟中,P-T轨迹记录了峰期前温压条件递增的过程,温度峰期与压力峰期同时到达,说明蓝片岩相变质作用是在俯冲过程中实现的,而不是折返过程中达到的。减压阶段的轨迹近于平行追溯进变质轨迹,揭示与进变质过程相似的地热体制下(11～14℃/km),相对缓慢的抬升过程  相似文献   

A Preliminary Study on the Soft–Sediment Deformation Structures in the Late Quaternary Lacustrine Sediments at Tashkorgan, Northeastern Pamir, China     

LIANG Lianji  DAI Fuchu  JIANG Hanchao  ZHONG Ning 《《地质学报》英文版》2018,92(4):1574-1591

This study identified soft–sediment deformation structures(SSDS) of seismic origin from lacustrine sediments in the late Quaternary paleo–dammed lake at Tashkorgan, northeastern Pamir. The observed deformation structures include sand dykes, liquefied diapir and convolute structures, gravity induced SSDS, and thixotropic pillar and tabular structures. We conducted a preliminary study on the morphology, formation and trigger mechanisms of pillar and tabular structures formed by liquefaction of underlying coarse sand and thixotropy of the upper silty clay. The regional tectonic setting and distribution of lacustrine strata indicate that the most probable trigger for the SSDS in lacustrine sediments was seismic activity, with an approximate earthquake magnitude of M6.0; the potential seismogenic fault is the southern part of the Kongur normal fault extensional system. AMS 14 C dating results indicate that the SSDS were formed by seismic events occurring between 26050±100 yr BP and 22710±80 yr BP, implying intense fault activity in this region during the late Pleistocene. This study provides new evidence for understanding tectonic activity and regional geodynamics in western China.  相似文献   

南海北部潮汕坳陷侏罗系沉积特征及对储层的控制作用研究   总被引：1，自引：1，他引：0       下载免费PDF全文

强昆生  张光学  张莉  吕宝凤  钟广见  冯常茂  易海  赵忠泉  杨振  鄢伟 《中国地质》2018,45(1):48-58

南海北部潮汕坳陷侏罗系具有很大的油气勘探潜力,沉积特征对其储层的发育具有明显的控制作用。通过对研究区最新地震资料精细解释,可以划分出4个典型地震反射界面和3个地震反射层,根据层序界面圈出侏罗系分布特征和残留厚度;通过地震相-沉积相转换对比分析研究,识别出侏罗纪地层不同时期的沉积相类型及其分布特征,重塑了潮汕坳陷侏罗系沉积演化史。该区主要发育5类沉积相、8种沉积亚相,其中滨岸三角洲前缘亚相和深水扇中亚相分别控制了碎屑流砂岩优质储层的发育;此外,浊流砂岩储层主要受控于物源供给的影响,距离三角洲砂体朵叶越近,滑塌浊积体数量越多,面积也越大。总体上,滨岸三角洲前缘亚相、深水扇中亚相和滑塌浊积体是研究区良好的储集相带,该类储集体由于埋藏较深加之被泥岩覆盖,对油气聚集较为有利。  相似文献   

Sedimentology and Sequence Stratigraphy of Marine to Lacustrine Deltaic Deposits in a Craton Basin and Their Controlling Factors: Shan 2 Member–He 8 Member (Guadalupian–Lopingian, Permian), Southeast Ordos Basin, North China     

SHAN Xin  YU Xinghe  Peter ?CLIFT  LI Yalong  JIN Lin  SU Dongxu  DU Yonghui  ZHOU Jinsong  HAN Xiaoqin 《《地质学报》英文版》2018,92(1):268-285

  相似文献   

柳河盆地中生代充填特征与盆地演化     

曲鹏展  程日辉  宋立斌  沈艳杰  许中杰 《世界地质》2018,37(1):185-198

柳河盆地中生代地层发育有中侏罗统侯家屯组,下白垩统果松组、鹰嘴砬子组、林子头组、下桦皮甸子组和亨通山组。主要岩石类型为碎屑岩、火山碎屑沉积岩、火山碎屑岩和熔岩,沉积相为扇三角洲-湖泊相。根据岩性变化和岩相组合,将下白垩统划分为13个三级层序和8种充填类型。根据盆地构造和层序特征,划分为5个构造发育阶段,分别是中侏罗世初始凹陷阶段、晚侏罗世抬升剥蚀阶段和早白垩世的3个火山喷发-沉降阶段。柳河盆地是一个受走滑张扭-走滑压扭机制控制的走滑伸展盆地。  相似文献   

新疆西昆仑汗铁热克一带侏罗纪沉积相与沉积环境分析     

刘海青 《地质与勘探》2018,54(S1):1434-1441

新疆西昆仑汗铁热克一带地处塔里木盆地西南缘,构造上属塔里木盆地与西昆仑造山带的结合部位,侏罗纪地层包括积莎里塔什组、康苏组、扬叶组、塔尔尕组和库孜贡苏组。根据岩性、颜色、粒度分析及沉积相标志等方法,将汗铁热克一带侏罗纪沉积环境与沉积相划分为冲积扇、扇三角洲和湖泊相,其沉积特征为侏罗纪早期快速充填,中期稳定沉降,晚期短暂的沉积间断后充填,并系统分析了研究区在整个侏罗纪沉积环境演化规律。  相似文献   

川西南荥经坳陷川荥页1井奥陶系沉积相与古生物特征及地层厘定          下载免费PDF全文

熊小辉  王剑  汪正江  熊国庆  邓奇  杨平 《沉积与特提斯地质》2018,38(3):16-24

对川西南荥经坳陷内三口页岩气井尤其是川荥页1井奥陶系开展了系统的岩心观察和分析。三口钻井在梁山组之下均发育十余米厚的灰黑色泥岩,其中川荥页1井灰黑色泥岩厚近16m。沉积相分析认为灰黑色泥岩为浅水陆棚相,泥岩之下发育的大套砂岩为滨岸近滨亚相,总体向上海水逐渐变深。砂岩中发育丰富的沉积软变形构造及波状交错层理、浪成沙纹层理、平行层理、斜层理等构造。川荥页1井上部泥岩中见大量三叶虫、笔石和腕足等化石及其碎片,鉴定表明含有代表中下奥陶统的常见生物分子,如对笔石(Didymograotus sp.)、大洪山虫(Taihungshania sp.)等。该套砂泥岩组合在沉积相及古生物化石等方面明显区别于荥经坳陷周缘奥陶系五峰组—志留系龙马溪组,与研究区及邻区中下奥陶统红石崖组、湄潭组、大湾组、大官山组中段等层位相当。  相似文献