共查询到18条相似文献，搜索用时 93 毫秒
1.
2.
滇西昌宁─孟连带南部地层地质问题 总被引：1，自引：1，他引：1
滇西孟连以南，整合于南段组浊积岩之上的拉巴群硅质岩含晚二叠世早期放射虫化石，南段组时代不仅限于石炭纪，可能延入二叠纪。二者为晚古生代思茅地块的外陆坡沉积。其西面的南基河杂岩（新名）由层序混乱的晚古生代硅质岩、泥岩和少量砂岩、玄武岩构成。放射虫化石证据表明，硅质岩时代不仅限于晚泥盆世－早二叠世，还延入晚二叠世，而有的砂岩时代为早石炭世，它们是经过强烈构造变动的古特提斯洋的沉积记录。昌宁－孟连带向南可能延至泰国北部的清迈带，而非东北部的难河带。 相似文献
3.
滇西昌宁─孟连带南部地层地质问题 总被引：4，自引：2，他引：4
滇西孟连以南，整合于南段组浊积岩之上的拉巴群硅质岩含晚二叠世早期放射虫化石，南段组时代不仅限于石炭纪，可能延入二叠纪。二者为晚古生代思茅地块的外陆坡沉积。其西面的南基河杂岩（新名）由层序混乱的晚古生代硅质岩、泥岩和少量砂岩、玄武岩构成。放射虫化石证据表明，硅质岩时代不仅限于晚泥盆世－早二叠世，还延入晚二叠世，而有的砂岩时代为早石炭世，它们是经过强烈构造变动的古特提斯洋的沉积记录。昌宁－孟连带向南可能延至泰国北部的清迈带，而非东北部的难河带。 相似文献
4.
通过对华南、思茅、保山、缅泰、印支、羌塘、拉萨和喜马拉雅地块进行了古纬度和纬度运移量的对比分析,以确定西藏和云南西部三江地区主要地块的碰撞拼合历史,以及相应的特提斯洋盆演化时限。结果表明:①分隔保山和思茅地块的古特提斯洋可能于早志留世张开;②保山与思茅地块于晚二叠世碰撞,然后继续和华南地块、缅泰地块一起向北漂移,直到晚三叠世;③古特提斯洋年龄范围在早志留世至晚二叠世之间;④中特提斯洋年龄范围在早二叠世至早白垩世之间,在晚三叠世达到其最大纬度宽度,约42°;⑤雅鲁藏布江缝合带所代表的新特提斯洋于晚三叠世张开。 相似文献
5.
放射虫硅质岩在中国南方及邻区广泛分布,有重要的古地理意义。按其时空分布,可分为南区及北区和东带。南区包括滇西、滇东南、桂西和桂南,主要为晚古生代至中生代早期放射虫硅质岩。滇西硅质岩带南延至泰国和马来西亚,代表古特提斯主支。滇东南、桂西和桂南的硅质岩则指示古特提斯多岛洋的分支海盆。北区包括两广中北部、湘赣中南部和长江中下游一带,主要为二叠纪中晚期放射虫硅质岩,标志当时扬子台缘与古特提斯洋连通的深水盆地。东带沿南海和东海外侧的岛弧分布,从菲律宾北巴拉望经琉球到西南日本内带,主要为中二叠世至晚侏罗世放射虫硅质岩,与古地磁证据一起指示了该期间华南南方一个低纬度的远洋盆地,可称为“古南中国海”。它的张开可能是中晚二叠世云开地体和中国东南部其他地方造山事件的原因,它的随后发展对华南东部三叠纪和侏罗纪古地理演化也有重大影响。晚侏罗世太平洋伊泽奈崎板块的迅速北移,使“古南中国海"俯冲消减,导致东南沿海大规模的钙碱性岩浆活动。 相似文献
6.
东南亚特提斯构造格架复杂,特别是印支板块西缘琅勃拉邦-黎府构造带构造演化及区域构造线连接更是争议不断. 通过老挝西北部填图工作,首次在黎府构造带北部南莫溪地区发现保存完整的蛇绿混杂岩,为探讨黎府构造带的属性以及区域古地理格局,选取了蛇绿混杂岩中的含放射虫硅质岩、辉长岩以及洋岛海山中的礁灰岩,开展了岩相学、古生物学、锆石LA?ICP?MS U?Pb年代学、岩石地球化学研究. 结果表明,该蛇绿混杂岩出露端元包括蛇纹岩、蛇纹石化橄榄岩、辉长岩、辉绿岩、玄武岩和硅质岩,蛇绿岩套层序特征完整;辉长岩LA?ICP?MS锆石U?Pb年龄为350.4±3.3 Ma,成岩为早石炭世;洋岛海山中珊瑚种属为Thamnopora sp.和Paracravenia sp.,所属时代为中二叠世;硅质岩岩石地球化学元素特征指示其为生物成因,沉积环境为洋盆或开阔的盆地环境,放射虫共鉴定出9属30种,所属时代为中泥盆世-早石炭世. 综合本次研究,反映出南莫溪蛇绿混杂岩所代表的洋盆具有长期的演化历史,从晚泥盆世开始,一直持续到中二叠世还未结束,演化时间至少超过135 Ma,指示了该蛇绿混杂岩代表残留的古特提斯洋盆,而非弧后盆地. 认为黎府构造带向北应与琅勃拉邦构造带相连,且该区域从晚泥盆世开始一直存在古特提斯洋. 相似文献
7.
滇西北中甸地区哈工组放射虫及其构造古地理意义 总被引：6，自引：2，他引：6
位于甘孜-理塘构造带和金沙江构造带之间的德格-中甸微板块,可分为乡城晚三叠世岛弧带、义敦晚三叠世弧后盆地带和中咱地块等次级构造单位.滇西北中甸地区上三叠统哈工组包含大量沉积混杂岩块,与乡城、得荣泥砾混杂岩相连,形成晚三叠世沉积混杂岩带.哈工组沉积序列和沉积混杂岩沉积特征研究表明,中甸地区沉积混杂岩带为义敦晚三叠世弧后盆地形成过程中,由盆地边缘垮塌沉积形成,混杂岩块物源为近源下伏地层.沉积混杂岩块主要为晚古生代灰岩,但也有含中泥盆世、早石炭世和中二叠世放射虫化石的层状硅质岩,说明德格-中甸微板块晚古生代不是统一的碳酸盐台地,而是碳酸盐台地与深水断陷盆地并存的构造古地理格局.另外,哈工组三段还发现侏罗纪放射虫化石,说明金沙江带以东地区侏罗纪仍存在海盆. 相似文献
8.
青藏高原龙木错-双湖板块缝合带与羌塘古特提斯洋演化记录 总被引：27，自引：17，他引：27
龙木错-双湖缝合带、西金乌兰-金沙江缝合带和昆仑-秦岭缝合带是青藏高原上3条主要的晚三叠世板块缝合带,目前的研究资料表明后2条缝合带不具备冈瓦纳北界的基本要素。简要介绍了龙木错-双湖缝合带中有关古特提斯洋存在的基本事实,即早古生代洋壳残片、二叠纪蛇绿岩、泥盆纪—二叠纪放射虫硅质岩、各类不同性质的增生岩片、2种类型的构造混杂岩带和蛇绿混杂岩盖层体系的时代与性质等,已有的资料初步确定羌塘古特提斯洋盆演化的时限为晚泥盆世到晚三叠世。认为龙木错-双湖缝合带是青藏高原上古特提斯洋消亡的主要场所,是恢复和反演青藏高原早期形成演化的最重要的窗口,也是地学界几十年关注的冈瓦纳大陆的北界。 相似文献
9.
泥盆纪—石炭纪放射虫硅质岩在西南天山广泛分布,从东部的独库公路沿线到西部的阿合奇中—吉边境构成一条深水沉积带。独库公路沿线已发现中泥盆世晚期至早石炭世维宪早期的放射虫硅质岩,可用“库勒湖组”统称。从志留系顶统科克铁克达坂组经下泥盆统阿尔腾柯斯组到库勒湖组的生物地层和沉积相研究表明了南天山洋从浅海到深水洋盆的演化过程。南天山洋是塔里木北缘浅海陆架裂解产生的小洋盆。构造古地理和生物古地理研究表明,南天山洋是古特提斯的分支洋盆,不属古亚洲洋范围。塔里木以南的古特提斯分支洋盆,在早石炭世及之后的继续扩张,使塔里木北移,导致南天山洋和准噶尔—北天山区的古亚洲洋在早石炭世晚期和晚石炭世相继消亡。 相似文献
10.
11.
The paleogeographic position of the North Qiangtang Block, as well as the origin of the Central Qiangtang Metamorphic Belt (CQMB) have subjected to considerable debate that hampers the understanding of the early evolution of the Paleo-Tethys Ocean. This study reports a new radiolarian fauna of a Famennian age (Late Devonian) from the ophiolitic mélange south of Gangtang Co, northern Tibet, including Callela parvispinosa Won, Entactinia foveolata Nazarov, and Plenoentactinia pinguis Won. The discovery of Devonian radiolarians in the CQMB strongly supports the model that the Longmu Co–Shuanghu suture zone represents the main branch of the Paleo-Tethys Ocean. A correlation of the Late Devonian radiolarian in Tethys realm reveals that the Longmu Co–Shuanghu suture zone was connected to the Changning–Menglian suture zone in western Yunnan, the Chiang Mai–Inthanon and Chanthaburi suture zones in Thailand, and the Bentong–Raub suture zone in Malay Peninsula. The synchronous advent of Late Devonian radiolarians suggests that the Paleo-Tethys Ocean may have opened during that time. 相似文献
12.
Tectonic Evolution of the Palaeo——Tethys in Changning——Menglian Belt and Adjacent Regions,Western Yunnan 总被引：5，自引：0，他引：5
Liu Benpei Feng Qinglai Fang Nianqiao
China University of Geosciences Beijing 《中国地质大学学报(英文版)》1991,(1)
The Changning-Menglian belt,located between theBaoshan-Gengma massif and the Simao-Lincangmassif in Western Yunnan,preserves the complete recordof a suture zone and the most continuous record of deepwater sedimentation,representing the main branch of thePalaeo-Tethys polyisland ocean in the Hercynian-Indo-sinian stage.This belt could be further subdivided into threetectono-lithofacies zones.In the east zone,terrigenouselastics,argillaceous,marl-argillaceous and silicate sediments lie on the metamorphosed Early Palaeozoic basement in concealed unconformity,representing deep watersediments on a passive continental margin.The centralzone,although the basement rocks are absent fromoutcropping here,includes a contemporary complexof various sedimentary types,among them one type is ofdeep ocean sediments represented by radiolarian beddedchert,appearing from at least early Early Devonian tothe Middle Triassic.Another type includes purecarbonates of the Early Carboniferous to the LatePermian,a type of shallow wa 相似文献
13.
Correlation of Tectono-Stratigraphic Units in Northern Thailand with Those of Western Yunnan (China)
Chongpan Chonglakmani School of Geotechnology Suranaree University of Technology Nakhon Ratchasima ThailandFeng Qinglai Faculty of Earth Sciences China University of Geosciences Wuhan Dieter Meischner Goettingen Center of Geosciences 《中国地质大学学报(英文版)》2001,12(3)
Ｔｈｅｃｏｒｒｅｌａｔｉｏｎｏｆｔｅｃｔｏｎｏ ｓｔｒａｔｉｇｒａｐｈｉｃｕｎｉｔｓｏｆＮｏｒｔｈｅｒｎＴｈａｉｌａｎｄｗｉｔｈｔｈｏｓｅｏｆＷｅｓｔｅｒｎＹｕｎｎａｎ (Ｃｈｉｎａ)ｉｓｓｔｉｌｌｌｉｔｔｌｅｕｎｄｅｒｓｔｏｏｄ ,ｐａｒｔｌｙｂｅｃａｕｓｅｏｆｔｈｅ ｐａｕｃｉｔｙｏｆｇｅｏｌｏｇｉｃａｌｄａｔａｆｒｏｍｔｈｅＵｎｉｏｎｏｆＭｙａｎｍａｒａｎｄｔｈｅＬａｏｓ,ａｎｄｐａｒｔｌｙｄｕｅｔｏｔｈｅｃｏｎｆｌｉｃｔｉｎｇｇｅｏｄｙｎａｍｉｃｃｏｎｃｅｐｔｓａｄｏｐｔｅｄｂｙｖａｒｉｏｕｓａ… 相似文献
14.
新特提斯洋是中生代位于北方欧亚大陆和南方冈瓦纳大陆之间的古大洋,它在青藏高原南部地区于新生代早期因印度-欧亚大陆碰撞而消亡,其遗迹为现今的印度河-雅鲁藏布缝合带。新特提斯洋打开以拉萨地块从冈瓦纳大陆的裂离为标志。准确约束新特提斯洋的开启时间是重建冈瓦纳大陆裂解过程和特提斯洋演化历史的关键,但目前学术界对于新特提斯洋的开启时间还存在很大争议,不同学科方法的认识从早二叠世到晚三叠世不等。本文对新特提斯洋南侧印度被动大陆边缘二叠纪—三叠纪沉积地层进行了系统的梳理,研究发现在早二叠世冰期结束之后,印度大陆北缘长期表现为稳定的沉积环境,显著的沉积环境变化仅发生在晚三叠世。晚三叠世的沉积环境变化伴随着沉积和沉降速率增加、沉积物源变化、双峰式火山活动以及古地理格局的重大改变。研究认为,晚三叠世印度大陆北缘沉积作用变化所记录的区域伸展作用很可能代表了新特提斯洋的开启。 相似文献
15.
《International Geology Review》2012,54(9):1072-1096
In this paper, we summarize results of studies on ophiolitic mélanges of the Bangong–Nujiang suture zone (BNSZ) and the Shiquanhe–Yongzhu–Jiali ophiolitic mélange belt (SYJMB) in central Tibet, and use these insights to constrain the nature and evolution of the Neo-Tethys oceanic basin in this region. The BNSZ is characterized by late Permian–Early Cretaceous ophiolitic fragments associated with thick sequences of Middle Triassic–Middle Jurassic flysch sediments. The BNSZ peridotites are similar to residual mantle related to mid-ocean-ridge basalts (MORBs) where the mantle was subsequently modified by interactions with the melt. The mafic rocks exhibit the mixing of various components, and the end-members range from MORB-types to island-arc tholeiites and ocean island basalts. The BNSZ ophiolites probably represent the main oceanic basin of the Neo-Tethys in central Tibet. The SYJMB ophiolitic sequences date from the Late Triassic to the Early Cretaceous, and they are dismembered and in fault contact with pre-Ordovician, Permian, and Jurassic–Early Cretaceous blocks. Geochemical and stratigraphic data are consistent with an origin in a short-lived intra-oceanic back-arc basin. The Neo-Tethys Ocean in central Tibet opened in the late Permian and widened during the Triassic. Southwards subduction started in the Late Triassic in the east and propagated westwards during the Jurassic. A short-lived back-arc basin developed in the middle and western parts of the oceanic basin from the Middle Jurassic to the Early Cretaceous. After the late Early Jurassic, the middle and western parts of the oceanic basin were subducted beneath the Southern Qiangtang terrane, separating the Nierong microcontinent from the Southern Qiangtang terrane. The closing of the Neo-Tethys Basin began in the east during the Early Jurassic and ended in the west during the early Late Cretaceous. 相似文献
16.
内蒙古阿拉善地区恩格尔乌苏缝合带二叠纪放射虫及其地质意义 总被引：6，自引：3，他引：3
报道了采自恩格尔乌苏缝合带的蛇绿混杂岩硅质外来岩块中的二叠纪阿尔拜虫目放射虫化石,包括3属7种,可以划分为2个放射虫化石组合,能够与日本、美国的放射虫化石带进行对比,其地质时代分别为早二叠世和中二叠世晚期—晚二叠世早期。恩格尔乌苏缝合带位于华北板块和塔里木板块之间,这些放射虫化石的发现为研究恩格尔乌苏缝合带的构造演化提供了新的证据。鉴于其中最新的放射虫组合的地质时代为中二叠世晚期—晚二叠世早期,认为华北板块与塔里木板块之间自中二叠世晚期—晚二叠世早期曾经存在古海洋,即华北板块和塔里木板块的拼合时间是晚二叠世晚期。 相似文献
17.
LI Guobiao WAN Xiaoqiao JIANG Ganqing HU Xiumian GOUDEM Nicolas HAN Hongdou CHEN Xi 《《地质学报》英文版》2007,81(6):917-924
As one of the mélanges in the southern side of the Yarlung-Zangbo suture zone, the Saiqu mélange in southern Tibet is important for understanding the evolution of the Neo-Tethys ocean. The age of the Saiqu mélange, however, has been debated due to the lack of reliable fossil evidence in matrix strata. Based on lithological similarities with platform strata in southern Tibet and limited fossils from exotic blocks, previous studies variously ascribed the Saiqu mélange to be Triassic in general, Late Triassic, or Late Cretaceous. Here we reported planktonic foraminiferal faunas from the matrix strata of the Saiqu mélange. The new fossils yield a Late Cretaceous age, which is so far the best age constraint for the mélange. Regional stratigraphic correlation indicates that the Cretaceous Oceanic Red Beds (CORBs) in Saiqu may be time equivalent to the CORBs of the Zongzhuo Formation in neighboring regions. Thus the Saiqu mélange should be correlated to the Upper Cretaceous Zongzhuo Formation rather than the Triassic Xiukang Group, as previously suggested. 相似文献
18.
地处古特提斯域的牡音河组是一套由放射虫硅质岩和凝灰岩组合而成、沉积速率极低的远洋沉积序列。它所包括的４个放射虫组合指示其形成时代为晚二叠世末至中三叠世，从而大大改变了我们以往对古特提斯演化所拟定的时间表。详细的岩相和岩石地球化学分析表明，牡音河组的中、下部与大洋岛弧的火山活动关系密切，上部则有接受更多陆源物质的趋向。这一沉积记录所反映的演化趋可能标志着古特提斯残留海的一次重大构造转折。但是，牡音河组内所有火山碎屑和陆源碎屑仅仅构成若干夹在正常远洋序列中的远源薄层，这意味着古特提斯残留海仍然具有相当规模，距离完全闭合尚远。就牡音河组与相邻一些地层单位的关系，探讨了若干造山带地层学研究中值得注意的基本问题 相似文献