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1.
Anshu K.Sinha 《地学前缘》2000,(Z1)
he 2500km long Indus\|Tsangpo Suture has been recognized as one of the best examples of continent to continent collisional Suture Zone. It has come into existence as a result of subduction followed by continental collision (55～60Ma) between Indian (Sinha, 1989, 1997; Sinha et al., 1999) and Eurasian plates. While considering the recent palaeogeographic reconstruction of Pangea during late Palaeozoic it appears that a southern belt of Asian microcontinents stretching from Iran and Afghanistan through southern Tibet to western Thailand, Malaysia and Sumatra, comprise several continental blocks and numerous fragments that have coalesced since the Mid\|Palaeozoic along with the closure of Tethys. The origin, migration, assembly and timing of accretion of all these blocks to their present geotectonic position is not well known and there is no Permo—Triassic crust left in the present day Indian Ocean. The oldest ocean crust adjacent to the west African and Antarctic margin is of early or middle Cretaceous age (approximately 140～100Ma) (Searle, 1991). The Karakoram\|Hindukush microplate in the west and the Qiangtang\|Lhasa block in the central and eastern segment of South Asia margin are among those blocks already welded with Asian plates around 120～130Ma ago, before the collision of India (55～60Ma) with the collage of plates forming Peri\|Gondwanian microcontinents. But the reconstruction of palaeogeographic configuration remain incomplete due to paucity of authentic geologic information available from Karakoram, Pamir and Western Tibet. Prior to our discovery no early Permian plant remains and palynomorphs were ever reported from Karakoram terrane. Our discovery of Early Permian remains and late Asselian (about 280～275Ma) palynomorphs provides crucial clue regarding the palaeogeographic reconstruction of the Karakoram\|Himalayan block in the Permian time. 相似文献
2.
塔里木板块内部发育了大量由早—中二叠世板内岩浆作用所形成的、以玄武岩类为主的基性岩浆岩,包括玄武岩、辉绿岩、玄武安山岩等,残余分布面积约20万km2。而二叠纪时期是塔里木板块演化过程中一个非常重要的转折时期,从早二叠世晚期开始塔里木板块结束了海相沉积,进入了陆相沉积阶段。通过对塔里木板块的岩浆作用特征和石炭纪—二叠纪沉积相的分析,笔者讨论了这一大规模的岩浆作用对板块晚石炭世—二叠纪的沉积作用所起的控制作用,提出了塔里木板块早—中二叠世巨量玄武质岩浆作用的沉积响应过程模式。 相似文献
3.
SHAHID GHAZI NIGEL P MOUNTNEY AFTAB AHMAD BUTT SADAF SHARIF 《Journal of Earth System Science》2012,121(5):1239-1255
The Early Permian Gondwana regime succession of the Nilawahan Group is exposed only in the Salt Range of Pakistan. After a prolonged episode of non-deposition that spanned much of the Palaeozoic, the 350?m thick predominantly clastic sequence of the Nilawahan Group records a late glacial and post-glacial episode in which a range of glacio-fluvial, marine and fluvial environments evolved and accumulated. The Early Permian succession of the Salt Range has been classified into four formations, which together indicates a changing climatic regime during the Early Permian in the Salt Range region. The lower-most, Tobra Formation unconformably overlies a Cambrian sequence and is composed of tillite, diamictite and fresh water facies, which contain a floral assemblage (Gangamopteris and Glossopteris) that confirms an Asselian age. The Tobra Formation is overlain by marginal marine deposits of the Dandot Formation (Sakmarian), which contain an abundant brachiopods assemblage (Eurydesma and Conularia). Accumulation of the Dandot Formation was terminated by a regional sea-level fall and a change to the deposition of the fluvial deposits of the Warchha Sandstone (Artinskian). The Warchha Sandstone was deposited by high sinuosity meandering, avulsion prone river with well developed floodplains. This episode of fluvial sedimentation was terminated by a widespread marine transgression, as represented by the abrupt upward transition to the overlying shallow marine Sardhai Formation (Kungurian). The Early Permian Gondwana sequence represented by the Nilawahan Group is capped by predominantly shallow shelf carbonate deposits of the Tethyan realm. The sedimentologic and stratigraphic relationship of these four lithostratigraphic units in the Salt Range reveals a complex stratigraphic history for the Early Permian, which is mainly controlled by eustatic sea-level change due to climatic variation associated with climatic amelioration at the end of the major Gondwana glacial episode, and the gradual regional northward drift to a lower latitude of the Indian plate. 相似文献
4.
In NW Himalayas, the suture zone between the collided Indian and the Karakoram plates is occupied by crust of the Cretaceous Kohistan Island\|Arc Terrane [1] . Late Cretaceous (about 90Ma) accretion with the southern margin of the Karakoram Plate at the site of the Shyok Suture Zone turned Kohistan to become an Andean\|type margin. The Neotethys was completely subducted at the southern margin of Kohistan by Early Tertiary, leading to collision between Kohistan and continental crust of the Indian plate at the site of the Main mantle thrust.More than 80% of the Kohistan terrane comprises plutonic rocks of (1) ultramafic to gabbroic composition forming the basal crust of the intra\|oceanic stage of the island arc, and (2) tonalite\|granodiorite\|granite composition belong to the Kohistan Batholith occupying much of the intermediate to shallow crust of the terrane mostly intruded in the Andean\|type margin stage [2] . Both these stages of subduction\|related magmatism were associated with volcanic and sedimentary rocks formed in Late Cretaceous and Early Tertiary basins. This study addresses tectonic configuration of Early Tertiary Drosh basin exposed in NW parts of the Kohistan terrane, immediately to the south of the Shyok Suture Zone. 相似文献
5.
K.S. Valdiya 《Tectonophysics》1984,105(1-4)
The compression and attendant deformation of a thick and vast sedimentary prism formed since Early Riphean times on the northern continental margin of the Indian craton gave rise to the Himalaya mountains as a result of convergence and collision of the Indian and Asian plates. The oceanic trench-sediments, tectonically implanted with sea-floor material and intimately associated with calc-al-kaline volcanics in the narrow Sindhu-Tsangpo belt extending from Kohistan through Dras, Leh, Darchen (Mansarovar) to Shigatse and beyond, represent the subduction-island arc complex which developed south of the dynamic southern margin of the Asian continent and was welded to the colliding Indian plate during the late Eocene to Oligocene period. This complex is fringed to the north by a wide zone of Andean-type granitic bodies. The evolution of the Himalayan orogen is closely connected with the development of the present-day Andaman-Nicobar-Indonesia island arc-subduction system in the southeast and the Makran Ranges-Oman Trench in the southwest.The evolution of the Himalaya was accomplished in four major phases of tectonic upheaval during the late Cretaceous to Palaeocene (Karakoram phase), late Eocene to Oligocene (Malla Johar phase), middle Miocene to Pontian (Sirmurian phase), and late Pliocene to middle Pleistocene (Siwalik phase). While the Karakoram phase marks the convergence of continents and the Malla Johar phase represents the collision and subduction, it was during the Sirmurian upheaval that the main tectonic features developed and the Himalaya acquired its distinctive structural complexion 相似文献
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8.
GUO Fuxiang Research Centre of Prediction of Hidden Ore Deposits Guilin Institute of Technology Guilin 《《地质学报》英文版》2000,74(1):1-6
The Kazakhstanian plate was near the Tarim, Sino-Korean and South China-Southeast Asian plates in the Middle-Late Cambrian and Late Ordovician, and approached the Siberian plate in the other periods of the Early Palaeozoic. The Hi and Toksun-Yamansu terranes had been split from the Tarim plate before the Middle Devonian and then went close to Angaraland in the late Early Permian. The Beishan area on the northeastern margin of the Tarim plate came close to Angaraland first in the early Early Permian. The suturing age between the Tarim and Ka-zakhstanian-Siberian plates is generally the same as that between the Turkey-Central Iran-Gangdise and South China-Southeast Asian plates. The suturing event took place in the early Early Permian, while the corresponding tectogeny occurred between the Early and Late Permian. 相似文献
9.
把柯坪断隆“还原”为塔里木板块的一部分,重塑了它与北邻的乌什地区和南邻的巴楚地区古生代“分分”“合合”的演化史,得到以下重要认识。（1）奥陶纪在乌什、柯坪和巴楚一间房地区发育以东西向的古吐木休克断层为南界的台盆;该断层的西段后期被柯坪塔格断裂（东西走向段）迁就利用,中—东段后期因被肢解而“消失”。（2）柯坪地区最西部中泥盆世已有海相沉积,晚泥盆世—石炭纪海侵不断向东扩展;因南天山洋的消减在柯坪—阿克苏—库车一线形成横贯塔里木北缘的石炭纪隆起带,使得塔里木中—北部上泥盆统—石炭系的沉积相有清楚的空间展布规律。（3）据同位素年龄值将柯坪地区东段玄武岩的时代更正为早二叠世,强烈火成活动造成的热隆升使该地区早二叠世即出现陆相沉积;塔西北的其他地区石炭纪末—早二叠世普遍发生海侵。（4）从与南天山洋和西昆仑洋耦合演化的角度简要探讨了塔里木西北地区古生代的成盆动力学背景,认为古生代有东西向、北西向及北东向的控盆和控相断裂发育并总结了其后期演化的特点。 相似文献
10.
序言前陆盆地是由板块碰撞引起侧向挤压,进而形成冲断推覆体(thrust mass)加载于大陆边缘,使大陆地壳周缘前陆隆起(peripheral forebulge)形成的一种不对称盆地,它的一侧与发育周缘前陆隆起的克拉通大陆为邻,另一侧靠近冲断推覆体。靠近冲断推覆体侧的一端主要发育陆源碎屑沉积,而靠近克拉通大陆的一边则发育成为碳酸盐台地。由于碰撞后大陆岩石圈的持续俯冲,造成冲断推覆体跨过先前被动大陆边缘,进而向克拉通陆内迁移发展,致使碳酸盐台地最终全被陆源碎屑掩埋。最初,冲断推覆体位于海平面之下,随着冲断推覆体叠加而成山链,加载于大陆边缘薄的外部地壳之上,沿缝合线形成一个深而狭长的边缘海槽地,接受陆源泥和深海沉积物沉 相似文献
11.
Mathieu Soret Kyle P. Larson John M. Cottle Matthijs Smit Alex Johnson Sudip Shrestha Asghar Ali Shah Faisal 《Journal of Metamorphic Geology》2019,37(5):633-666
The Karakoram–Hindu Kush–Pamir and adjacent Tibetan plateau belt comprise a series of Gondwana‐derived crustal fragments that successively accreted to the Eurasian margin in the Mesozoic as the result of the progressive Tethys ocean closure. These domains provide unique insights into the thermal and structural history of the Mesozoic to Cenozoic Eurasian plate margin, which are critical to inform the initial boundary conditions (e.g. crustal thickness, structure and thermo‐mechanical properties) for the subsequent development of the large and hot Tibetan–Himalaya orogen, and the associated crustal deformation processes. Using a combination of microstructural analyses, thermobarometry modelling and U–Th–Pb monazite and Lu–Hf garnet geochronology, the study reappraises the metamorphic history of exposed mid‐crustal metapelites in the Chitral region of the South Pamir–Hindu Kush (NW Pakistan). This study also demonstrates that trace elements in monazite (especially Y and Dy), combined with thermodynamical modelling and Lu–Hf garnet dating, provides a powerful integrated toolbox for constraining long‐lived and polyphased tectono‐metamorphic histories in all their spatial and temporal complexity. Rocks from the Chitral region were progressively deformed and metamorphosed at sub‐ and supra‐solidus conditions through at least four distinct episodes from the Mesozoic to the Cenozoic. Rocks were first metamorphosed at ~400–500°C and ~0.3 GPa in the Late Triassic–Early Jurassic (210–185 Ma), likely in response to the accretion of the Karakoram during the Cimmerian orogeny. Pressure and temperature subsequently increased by ~0.3 GPa and 100°C in the Early‐ to Mid Cretaceous (140–80 Ma), coinciding with the intrusion of calcalkaline granitic plutons across the Karakoram and Pamir regions. This event is interpreted as the record of crustal thickening and the development of a proto‐plateau within the Eurasian margin due to a long‐lived episode of slab flattening in an Andean‐type margin. Peak metamorphism was reached in the Late Eocene–Early Oligocene (40–30 Ma) at conditions of 580–600°C and ~0.6 GPa and 700–750°C and 0.7–0.8 GPa for the investigated staurolite schists and sillimanite migmatites respectively. This crustal heating up to moderate anatexis likely resulted in the underthrusting of the Indian plate after a NeoTethyan slab‐break off or to the Tethyan Himalaya–Lhasa microcontinent collision and subsequent oceanic slab flattening. Near‐isothermal decompression/exhumation followed in the Late Oligocene (28–23 Ma) as marked by a pressure decrease in excess of ~0.1 GPa. This event was coeval with the intrusion of the 24 Ma Garam Chasma leucogranite. This rapid exhumation is interpreted to be related to the reactivation of the South Pamir–Karakoram suture zone during the ongoing collision with India. The findings of this study confirm that significant crustal shortening and thickening of the south Eurasian margin occurred during the Mesozoic in an accretionary‐type tectonic setting through successive episodes of terrane accretions and probably slab flattening, transiently increasing the coupling at the plate interface. Moreover, they indicate that the south Eurasian margin was already hot and thickened prior to Cenozoic collision with India, which has important implications for orogen‐scale strain‐accommodation mechanisms. 相似文献
12.
根据新疆柯坪，乌什的Ting类化石新材料，结合以往有关Ting类生物地层学及Ting类古地理分布的资料，分析了塔里木地区二叠纪Ting类化石组合特征。研究结果显示，塔里木盆地早二叠世Ting类动物群与我国西南地区同期Ting类动物群面貌非常相似，并具有一些目前仅发现于云南，贵州和广西的地方性种类，表明塔里木板块与华南板块在这一时期应处于相同的纬度，且两者相对位置似应比较接近。但是，这一结论与有关古地磁资料不尽吻合。针对这一问题，结合有关石炭－二叠纪微板块运动及古洋运动方向的研究成果，对塔里木，华南板块早二叠世Ting类动物群相似性产生的原因进行了讨论。 相似文献
13.
黑龙江多宝山古生代海盆闭合的岩石学证据 总被引：2，自引：0，他引：2
综合研究黑龙江多宝山地区古生代沉积地层、生物化石,通过分析侵入岩岩石地球化学及其锆石U--Pb 同位素测年资料,表明该地区早奥陶世至晚泥盆世早期为海相沉积地层,晚泥盆世晚期为海陆交互相沉积地层,早石炭世为陆相河湖沉积地层。多宝山海盆东南侧出露一套年龄为( 300 ± 3 ～ 357 ± 4) Ma 的花岗岩,其中正长、二长花岗质糜棱岩为后造山花岗岩,碱长花岗岩为造山后A 型花岗岩。表明多宝山海盆于晚泥盆世开始闭合,至早石炭世为陆相河湖沉积,晚石炭世-早二叠世为抬升剥蚀阶段。表现为多宝山地区于早石炭世开始造山,晚石炭世晚期或延至早二叠世发生造山后伸展作用。 相似文献
14.
四川海相克拉通盆地显生宙演化阶段及其特征 总被引：2，自引：1，他引：1
四川叠合盆地是在四川海相克拉通盆地基础上形成的。本文利用最新的钻井资料、地震资料及其研究成果,详细阐述了四川海相克拉通盆地在显生宙的演化阶段及其特征。研究结果发现,四川海相克拉通盆地显生宙演化可分为早晚两期,早期为晚震旦世-石炭纪,晚期为二叠纪-中三叠世。两期克拉通演化都经历了早期弱拉张,后期弱挤压阶段。弱拉张初始阶段都有一次海相碳酸盐岩的大面积稳定沉积(震旦系灯影组和二叠系栖霞-茅口组)和随后的隆升剥蚀作用及风化壳岩溶作用。其后进入弱拉张期,发育拉张槽,拉张强度最大的部位均位于克拉通的西北部,都是从克拉通的西北部边缘向克拉通内部减弱。然而,两期拉张槽的充填特征不同,早寒武世绵阳-长宁拉张槽是补偿型充填,与拉张槽周缘相比,拉张槽内沉积厚度巨大;晚二叠世-早三叠世开江-梁平拉张槽为欠补偿型充填,与拉张槽周缘相比,拉张槽内沉积厚度非常薄。拉张期结束后进入弱挤压阶段,形成古隆起,挤压强度最大的部位均位于克拉通的西南部,都是从克拉通的西南边缘向克拉通内部减弱。弱拉张阶段的拉张槽与弱挤压阶段的古隆起均为大角度相交关系;然而,拉张槽和古隆起的规模差别较大,早寒武世绵阳-长宁拉张槽面积约5.4×10~4km~2,对应的加里东期乐山-龙女寺古隆起面积6×10~4km~2;晚二叠世-早三叠世开江-梁平拉张槽面积约2.0×10~4km~2,对应的印支期开江古隆起面积0.8×10~4km~2;晚二叠世-早三叠世蓬溪-武胜拉张槽面积约1.5×10~4km~2,对应的印支期泸州古隆起面积4.2×10~4km~2。绵阳-长宁拉张槽的规模比开江-梁平拉张槽、蓬溪-武胜拉张槽要大,乐山-龙女寺古隆起的规模也大于泸州-开江古隆起的规模。四川海相克拉通盆地显生宙演化特征在很大程度上控制了四川叠合盆地海相油气地质条件的发育和油气藏的形成分布。 相似文献
15.
Coronas and high-P veins in metagabbros of the Kohistan island arc, northern Pakistan: evidence for crustal thickening during cooling 总被引：2，自引：0，他引：2
Abstract The E-W-trending Kohistan terrane in the NW Himalaya is a sandwich of a magmatic arc between the collided Karakoram (Asian) and Indian plates. The southern part of the Kohistan arc is principally made up of amphibolites derived from volcanic and plutonic rocks of Early Cretaceous age. Gabbroic relics in the amphibolites display calc-alkaline character, and their mineralogy is similar to low-P plutonic rocks reported from modern and ancient island arcs. The largest of these relics, occurring along the southern margin of the amphibolite belt near Khwaza Khela, is subcircular in outline and is about 1 km across. It consists of cumulate gabbros and related rocks displaying a record of cooling and crustal thickening. Primary olivine and anorthite reacted to produce coronas consisting of two pyroxenes +Mg-Fe2+ -Al spinel ± tschermakitic hornblende at about 800° C, 5.5–7.5 kbar. This thermotectonic event is of regional extent and may be related to the overthrusting of the Karakoram plate onto the Kohistan arc some 85 Ma ago, or even earlier. Later the gabbros were locally traversed by veins containing high-P assemblages: garnet, kyanite, zoisite, paragonite, oligoclase, calcite, scapolite and quartz ° Chlorite ° Corundum ± diopside. Formed in the range 510–600° C, and 10–12 kbar, these suggest further thickening and cooling of the crust before its uplift during the Tertiary. This paper presents microprobe data on the minerals, and discusses the tectonic implications of the coronitic and vein assemblages in the gabbros. 相似文献
16.
中国北方地区二叠纪岩相古地理 总被引：7，自引：1，他引：7
主要以实地踏勘和测量建立的87个标准剖面及529个辅助剖面为基础，通过对二叠系分布格局、岩石学特征、沉积构造特征、古气候、古生态、古环境等分析，来恢复中国北方地区二叠纪的古地理面貌。早二叠世：主要存在额尔古纳和佳木斯古陆，塔里木-敦煌-祁连-内蒙古古陆；海域主要分布在松辽海相区，华北残留海湾相区，柴西残留海湾相区和南准噶尔-吐哈-北山残留海湾相区；此外还有塔里木西部碳酸盐台地相区和准噶尔腹部河湖相区。中二叠世：早二叠世的古陆依然存在，但华北北部古陆范围明显缩小，而准噶尔南缘-吐哈地区已上升成为陆地；海域只局限在东北和南祁连地区，华北地区-北祁连地区大面积为河湖相发育区；塔里木盆地主要为陆相碎屑岩沉积；准噶尔地区发育河湖相沉积，北山残留海盆火山碎屑岩发育。晚二叠世：仅在南祁连地区有海相沉积，其他地区均为陆相沉积，东北地区陆相和湖泊相沉积占主导地位；华北地区-北祁连地区主体为河湖相沉积；塔里木盆地整体为河湖相沉积；准噶尔-吐哈盆地主体为河湖相沉积。 相似文献
17.
Shelf, forereef and basin margin (slope) olistoliths (Exotic blocks of limestone) of Permian–Jurassic age are tectonically juxtaposed within the Triassic to Eocene age pre-orogenic, deep abyssal plain turbidites of the Lamayuru. The pre-collision tectonic setting and depositional environment of the limestone olistoliths can be reconstructed from within the neighbouring Zanskar range. The disorganized Ophiolitic Melange Zone, an association of different tectonic rock slivers of Jurassic–Eocene age, is tectonically underlain by the overthrusted Lamayuru Formation and tectonically overlain by the Nindam Formation. Tectonic slivers of Late Jurassic–Early Cretaceous age red radiolarian cherts represent a characteristic lithotectonic unit of the Ophiolitic Melange Zone, those occurring near the contact zone with the Lamayuru Formation, were deposited within the neo-Tethyan deep-ocean floor of the Indian passive margin below the carbonate compensation depth. These tectonic slivers accumulated along the northern margin of the Indus–Yarlung Suture Zone of the Ladakh Indian Himalaya during subduction accretion associated with the initial convergence of the Indian plate beneath the Eurasian plate. 相似文献
18.
《Gondwana Research》2016,29(4):1530-1542
In this study, we conducted profile measurements, gravel composition analyses, and U–Pb dating on detrital zircons from a representative glacial marine diamictite in the Gangmaco–Dabure area of the Southern Qiangtang–Baoshan block, Tibetan Plateau. We conclude that the diamictite was formed in a glacial marine environment from the outer edge of the continental shelf to the continental slope and deep sea, in what is now the Southern Qiangtang–Baoshan block. Four distinct glacial–interglacial cycles were identified in the diamictite, which record a minimum of four stages of Gondwana glaciation in the area of the Southern Qiangtang–Baoshan block. Combined with regional geological information, we also conclude that during the Carboniferous–Permian, sediments containing the glacial marine diamictite derived from Gondwana, in the region extending from India to the Tethys Himalaya area, and Lhasa and Southern Qiangtang–Baoshan blocks, recorded the transition from continental, neritic to abyssal environments. Gravel assemblages and U–Pb dating of detrital zircons in the glacial marine diamictite indicate that the provenance of the diamictite was Indian Gondwana. We infer that during the Late Paleozoic, the northern margin of the Indian Gondwana continued to be influenced by the Early Palaeozoic tectonic set-up, when Indian Gondwana was under an erosional regime, and the Tethys Himalaya area, and Lhasa and Southern Qiangtang–Baoshan blocks were deposited on a passive continental margin. 相似文献
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西藏西部狮泉河地区二叠纪和三叠纪牙形石的发现及其意义 总被引：2，自引：3，他引：2
西藏西部阿里狮泉河地区的昂杰组、下拉组和左左组中发现牙形石化石。昂杰组的牙形石组合大致对比于中二叠世空谷期早中期Mesogondolella idahoensis-Vjalovognathus shindyensis组合带。下拉组顶部的牙形石组合大致对比于晚二叠世长兴期晚期Clarkina changxingensis带。左左组中含有早三叠世的Neospathodus sp.和Gladigondolella sp.,左左组和下拉组整合接触,左左组主体时代为三叠纪。狮泉河地区在早二叠世末期就开始由冈瓦纳相碎屑岩沉积转变为特提斯相碳酸盐岩沉积,在晚二叠世长兴期和早三叠世依然维持在海相沉积环境中。冈底斯西部在晚二叠世和三叠纪为古陆的观点有待于重新审视。 相似文献