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1.
西藏羌塘盆地可分为北羌塘坳陷、中央隆起带和南羌塘坳陷3个二级构造单元。在早及中三叠世,羌塘盆地具相似的岩相古地理格局,北羌塘坳陷受可可西里-巴颜喀拉海槽的海侵作用,表现为陆表海沉积,而南羌塘坳陷和中央隆起带此时处于剥蚀环境。至晚三叠世,受班公湖-怒江洋扩张作用的影响,除中央隆起带西段继续遭受剥蚀外,羌塘盆地普遍接受沉积。南北羌塘水域虽经双湖海峡连为一体,但盆地性质发生根本性变化,构造岩相组合也明显不同。南羌塘盆地为班公湖-怒江洋北侧的扩张边缘海盆,而北羌塘则是可可西里-巴颜喀拉造山作用下的前陆盆地。羌塘盆地三叠纪岩相古地理具有“东西呈带,带中分块”的格局,这一特点是区域构造演化和基底断裂联合作用所致。 相似文献
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在大量的区域地质调研和野外露头观测资料基础上,详细研究了西藏羌塘盆地东部中生代不同构造单元的沉积充填序列、地层发育特征与接触关系、构造界面性质、沉积体系配置和沉积相分布等,阐述了盆地沉积与周缘构造带演化之间的耦合关系,重建了研究区中生代不同时期的构造古地理面貌。研究表明,羌塘盆地是一个大型叠复式盆地,盆地东部中生代有海相、海陆过渡相和陆相3个沉积体系组、9个沉积体系和多个沉积（亚）相。盆地内部包括南羌塘坳陷、北羌塘坳陷、唐古拉山隆起带,以及不同时期的次级凸起与断凹等构造单元。其中,多玛断凹是以前石炭纪构造片岩为基底的侏罗纪-早白垩世早期被动大陆边缘陆表海盆地,早白垩世晚期转换为前陆盆地,晚白垩世以来与索县-左贡断凹联合为一体,在陆内造山过程中经历了压陷型盆地充填演化阶段。索县-左贡断凹是在晚三叠世班公湖-怒江沟-弧-盆体系基础上发展起来的前陆盆地。北羌塘坳陷是以华力西期开心岭-杂多隆起带为基底,经过晚三叠世昌都前陆盆地沉积、早侏罗世断陷盆地火山-沉积作用之后,于中侏罗世与索县-左贡断凹联合为一体,形成北羌塘-昌都巨型坳陷型盆地。白垩纪北羌塘陆块和昌都陆块处于隆升剥蚀状态。 相似文献
3.
羌塘盆地东部基底由前石炭纪吉塘岩群组成,沉积盖层为晚古生代一白垩纪地层。其中,中生代海相地层在盆地内分布广泛,沉积体系多样,构造古地理转换频繁。中生代盆地包括南羌塘坳陷、唐古拉山隆起带、北羌塘坳陷等3个构造单元,内部又可以划分出不同时期多个次级凹陷和凸起。盆地的发展和演化既受南、北两侧板块结合带控制,又受盆地内部被分划性断裂带围限的各断块差异性活动约束,依次经历了晚三叠世前陆盆地阶段,“北羌塘”早-中侏罗世伸展裂陷盆地发育阶段,多玛侏罗纪-早白垩世早期被动大陆边缘陆表海盆地发展阶段、晚期前陆盆地阶段,晚白垩世南羌塘山间压陷盆地演化阶段。实质上,该盆地是不同时期原型盆地有序叠加而构成的大型叠复式盆地。 相似文献
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应用地层对比、砂岩岩相学和碎屑锆石U-Pb年代学的方法,重建东巧—北拉地区物源转换和班公湖—怒江洋多期次俯冲及微陆块的拼合过程。研究表明：东卡错微陆块南侧的中下侏罗统希湖群下段表现为上三叠统确哈拉群的再旋回沉积,而北侧上段则开始出现来自羌塘地区的物质。这标志着北侧早侏罗世俯冲的东巧分支洋盆消亡,东卡错微陆块在中侏罗世与羌塘地块拼合开始形成初始周缘前陆盆地。接奴群的物源完全来自南羌塘地区,表明周缘前陆盆地在微陆块南侧北拉洋俯冲挤压下持续发育。晚侏罗世—早白垩世(147～141 Ma)拉萨地块和羌塘地块东西向全面碰撞,至早白垩世晚期(约120 Ma)南侧的分支洋盆北拉洋消亡代表碰撞结束。南羌塘地区受班公湖—怒江洋俯冲作用控制在早侏罗世发育由弧前—岩浆弧—弧后盆地组成的“一隆两坳”古地貌,并沉积了曲色组页岩和布曲组石灰岩。微陆块碰撞导致南羌塘盆地的隆起和海平面的下降,形成夏里组含膏质泥岩的潮坪相沉积。随着拉萨地块和羌塘地块的全面碰撞,南羌塘盆地从弧相关盆地卷入前陆盆地褶皱冲断带中,发生差异埋藏和隆升剥蚀。晚侏罗世—早白垩世,南羌塘盆地曲色组烃源岩和布曲组石灰岩在构造挤压作用下发生快速埋藏,进... 相似文献
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《古地理学报》2016,(6)
盆地原型研究有助于恢复盆地构造-岩相古地理和揭示盆山耦合,对油气勘探具有重要的指导意义。文中利用最新的钻井、地震及露头资料,以沉积相为研究实体,运用盆-山结合的思路,由点→线→面进行分析,重建了塔里木盆地中奥陶世一间房组沉积时期的构造-沉积环境,研究了原型盆地特征及性质。一间房组沉积时期,巴楚—塔中和塘南台内隆起为暴露剥蚀区;顺南—塘古巴斯—玉东台内洼地区发育低能的泥晶灰岩相;塔北和古城台地区发育大面积的台内颗粒滩相;柯坪台盆区发育深水瘤状灰岩—黑色页岩相;塔东深水盆地区经历了黑色页岩相→陆源碎屑浊积岩相的演变;库鲁克塔格—罗西台地区为继承发育的开阔台地相。该时期塔里木盆地构造-沉积格局具有由早奥陶世东西分异的台盆格局向晚奥陶世南北分异的隆坳格局过渡的特征,表现为塔西台地古地貌的分异和塔东深水盆地沉积性质的反转。该时期塔里木盆地整体具有克拉通内拗陷与边缘拗陷复合的性质,但在塔西克拉通内坳陷的南部叠加了前陆盆地的性质(塘南前隆和顺南—塘古巴斯—玉东后隆坳陷),在其西北部叠加了裂陷盆地的性质(柯坪克拉通边缘裂陷)。该时期塔里木盆地构造-沉积环境与原型盆地特征是其对周缘大地构造运动的响应。 相似文献
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依据近年来最新资料,通过对羌塘盆地南、北边界构造带构造属性、地球动力学机制及构造演化历程的讨论,剖析了羌塘盆地晚三叠世构造属性与盆地演化历程;在对盆地内部不同位置上三叠统岩性、岩相研究的基础上,通过不同古地理背景下层序界面与体系域界面的识别,建立了羌塘盆地晚三叠世层序地层格架,讨论了煤层在层序格架下的位置、聚煤特征及空间分布规律。研究表明,羌塘盆地晚三叠世为一复杂叠合盆地,经历了晚三叠世早、中期被动陆缘盆地,晚三叠世晚期羌北前陆盆地和羌南被动陆缘裂陷-坳陷盆地等不同的盆地演化历程;上三叠统构成一个完整的构造层序和两个三级层序,煤层位于高位体系域中上部,主要受控于高频率低级次海平面变化。具含煤岩系厚度大,煤层层数多,单层厚度小的特征;三角洲平原地带有利于煤层发育,三角洲沉积体系沿分割羌南、羌北盆地的中央隆起带发育,进一步指出该带是羌塘盆地内今后重要的找煤方向,并得到新发现的赛包玛煤点验证。 相似文献
8.
晚三叠世—中侏罗世中国南方前陆盆地构造格局的形成与演化 总被引：2，自引：1，他引：2
晚三叠世—中侏罗世在中国南方的构造历史上是一个十分重要的转折时期,原来较为稳定的华南板块裂解为扬子板块和东南板块,并由原先的台地沉积转变为前陆盆地沉积。在扬子板块南、北两缘逐渐形成了南前陆盆地带和北前陆盆地带,同时在扬子板块东南侧还存在一裂陷盆地带。根据该区的沉积、构造等特征,又可划分出三个阶段:晚三叠世早—中期,晚三叠世晚期—早侏罗世,中侏罗世。其中晚三叠世晚期—早侏罗世为前陆盆地发育的鼎盛时期,此时的北前陆盆地带自西向东主要由上扬子、中扬子、下扬子三个周缘前陆盆地及合肥冲断前渊盆地构成;南前陆盆地带主要由兰坪—思茅、楚雄、南盘江、桂东南等四个弧后前陆盆地及湘西、湘赣等冲断前渊盆地(群)构成。北前陆盆地带属周缘前陆盆地性质,而南前陆盆地带主要为弧后前陆盆地性质。同一前陆盆地带在上述三个不同阶段有不同的沉积—构造特征,而且在同一前陆盆地带内的不同盆地,其形成与演化的时间也有差异。前陆盆地的演化均与相邻造山带演化相关,造山带隆起的强度愈大,持续时间愈长,则相邻前陆盆地的沉积厚度亦愈大。 相似文献
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羌塘地区晚三叠世构造-古地理面貌总体呈多岛海格局,自北向南可分出3个次级构造-古地理单元:北羌塘弧后前陆盆地、龙木错-双湖残留盆地、南羌塘边缘海。北羌塘前陆盆地又分出5个古地理单元:以复理石沉积为特征的藏夏河-明境湖半深海;以细碎屑岩沉积为特征的唐古拉浅海陆棚;以碳酸盐沉积为特征的菊花山台地;以含煤碎屑岩系沉积为特征的土门格拉-双湖滨岸-三角洲和以酸性火山岩-火山碎屑岩喷发为特征的那底岗日-各拉丹东火山岛弧。盆地基底显示为南浅北深的箕状格局;盆地充填物为南薄北厚的楔形沉积体;盆地具有双物源、沉降中心和沉积中心不一致等特征,表明北羌塘盆地具有前陆盆地构造-沉积特征。南羌塘边缘海自北向南可分出3个古地理单元:以基性火山岩、碳酸盐岩和砂泥质碎屑岩为特征的肖茶卡浅海;以碳酸盐岩为特征的日干配错台地;以泥页岩夹粉砂岩、泥质灰岩为特征的南羌塘南缘半深海。南羌塘盆地基底显示为南、北低,中部高的丘状格局,盆地充填物为南薄北厚的楔形沉积体;盆地物源来自北部的中央隆起和那底岗日岛弧、盆地沉降中心在北部,而沉积中心在南部等特征,表明南羌塘盆地具有边缘海构造-沉积特征。羌塘地区晚三叠世构造-古地理研究对恢复南、北羌塘原型盆地的构造属性具有重要意义。 相似文献
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由于资料的欠缺和分布的不均衡,羌塘盆地构造-岩相古地理研究程度总体不高,不能为烃源岩和储层的分布预测提供依据。基于盆地属性、沉积体系及组合-耦合关系的研究,解决了资料丰富区域沉积相解释的多解性、资料缺少区域沉积相预测缺乏沉积模式指导的问题,取得以下3方面的成果和认识：(1)系统梳理了可可西里—金沙江洋、班公湖—怒江洋、龙木错-双湖洋的闭合史,明确了羌塘盆地属性,指出北羌塘地块在晚三叠世—早白垩世经历了复合前陆盆地、陆内弱挤压残留海盆地、褶皱-冲断快速抬升剥蚀3个构造演化阶段,南羌塘地块在晚三叠世—早白垩世经历了被动陆缘、活动陆缘、褶皱-冲断快速抬升剥蚀3个构造演化阶段,明确了8个关键沉积时期的盆地属性。(2)基于盆地属性、沉积体系及组合-耦合关系,系统恢复了羌塘盆地晚三叠世—早白垩世10个关键地质时期的构造-岩相古地理背景,揭示了构造对沉积的控制作用,提高了资料缺少区域沉积相预测的准确度。(3)明确了烃源岩和储层发育的构造-岩相古地理背景,认为上三叠统波里拉组—巴贡组烃源岩的分布受控于前陆坳陷、被动陆缘深水陆棚等构造单元,下侏罗统曲色组烃源岩的分布受控于弧后伸展盆地、陆内弱挤压残留海盆... 相似文献
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Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco. 相似文献
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Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414. 相似文献
13.
The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引：4，自引：0，他引：4
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species. 相似文献
14.
Muriel Rocher Stéphane Baize Stéphane Jaillet Edward Marc Cushing Yannick Lozac&#x;h Francis Lemeille 《Comptes Rendus Geoscience》2003,335(8):701-708
Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ1 roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003). 相似文献
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正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level 相似文献
16.
正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7), 相似文献
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正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci- 相似文献
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正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli- 相似文献
20.
正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.) 相似文献