喜马拉雅碰撞带的构造演化

通过对喜马拉雅碰撞带构造单元划分和组成的研究，从俯冲和碰撞带前缘加积作用，深层底辟和热隆扩展作用及岩石圈深物质流动－“回流”作用等３个方面阐明了喜马拉雅碰撞带的构造演化，提出了喜马拉雅碰撞带的构造演化模式－渐进式陆内变形模式。     

喜马拉雅造山带地震活动及其相关地质灾害

喜马拉雅造山带是地球上海拔最高、规模最大的陆陆板块俯冲碰撞带在这条长达2 500 km的板块边界上,近年来多次发生破坏性地震,造成大规模的滑坡、房屋倒塌等次生灾害,给人民生命和财产安全造成严重的威胁。分别选取尼泊尔喜马拉雅、喜马拉雅东构造结和喜马拉雅西构造结地区近期发生的3个地震震群作为研究实例,基于中国科学院青藏高原研究所在研究区架设的区域流动地震台站记录的波形资料,对地震的震源位置和震源机制解进行计算。结果表明,在尼泊尔喜马拉雅地区,主喜马拉雅逆冲断裂是大地震的主要发震构造;东构造结地区的地震以逆冲和走滑型为主,表明印度板块向北东方向的逆冲推覆和青藏高原向东南逃逸的侧向挤出是该地区的主要构造背景;西构造结地区中深源地震多发,揭示了高角度大陆深俯冲的几何形态。     

Seismic Activity in the Himalayan Orogenic Belt and Its Related Geohazards

Himalayan orogenic belt is the highest and largest continental collision and subduction zone on the Earth. The Himalayan orogenic belt has produced frequent large earthquakes and caused several geohazards due to landslides and housing collapse, having an impact on the safety of life and property along a length of over 2500 km. Here we took three earthquake clusters as examples, which occurred at Nepal Himalaya, eastern Himalayan syntaxis and western Himalayan syntaxis, respectively. Here we calculated the earthquake locations and fault plane solutions based on the waveform data recorded by seismic stations deployed in source areas by the Institute of Tibetan Plateau Research, Chinese Academy of Sciences. We found that at the Nepal Himalayan, the Main Himalayan Thrust is the major tectonic structure for large earthquakes to occur. At the eastern Himalayan syntaxis, most earthquakes are of the reverse or strike-slip faulting. The major tectonic feature is the combination of the NE-dipping thrust with the southeastern escape of the Tibetan plateau. At the western Himalayan syntaxis, intermediate-depth earthquakes are active. These observations reveal the geometry of the deep subduction of the continental plate with steep dipping angle.     

喜马拉雅碰撞带陆壳增厚和隆升机制——一种陆壳构造演化模式

“回流”是大陆碰撞带内普遍发生的一种构造-物理过程。本文基于喜马拉雅碰撞带的地质、地球物理事实,提出“回流”模式,以阐明喜马拉雅碰撞带各种地质、地球物理过程的内在联系,揭示大陆碰撞带的构造演化规律。     

IS THE GRENVILLE PROVINCE AN ANCIENT ANALOGUE OF THE HIMALAYAN BELT?

IS THE GRENVILLE PROVINCE AN ANCIENT ANALOGUE OF THE HIMALAYAN BELT?1　All埁ｇｒｅＣＪ ,2 4others.StructureandevolutionoftheHimalayan Tibetorogenicbelt[J].Nature ,1984,30 7:17～ 2 2 . 2　BurgJP ,DavyP ,MartinodJ .Shorteningofanaloguemodelsofthecontinentallithosphere :Newhypothesisforthefor mationoftheTibetanplateau[J].Tectonics ,1994,13:475～ 483. 3　BurtmanVS ,MolnarP .GeologicalandgeophysicalevidencefordeepsubductionofcontinentalcrustbeneaththePamir[C]…     

藏东缘昌都大型复合盆地喜马拉雅期陆内造山与成矿作用

研究藏东缘大型复合盆地喜山期陆内造山与成矿作用的目的,在于建立横断山型陆内碰撞造山构造模式、成岩成矿模式。根据地层接触关系、构造变形特征、矿床分布规律的研究,证实盖层褶皱推覆运动发生在早喜马拉雅期;盆地内的推覆(滑覆)构造圈闭、走滑断裂构造圈闭、走滑推覆脆-韧性剪切带圈闭、与造山带走向近直交的横向构造圈闭是主要的成岩、成矿空间。通过横断山型陆内造山动力学和喜山期成矿作用研究,分别建立了“横断山型”陆内碰撞造山模式和藏东缘大型复合盆地的成岩成矿模式。     

全球典型大陆造山带中榴辉岩的折返机制:来自变质岩和地球物理的限制

大陆岩石圈深俯冲作用是地球科学领域的前沿热点,榴辉岩的折返机制是板块构造及动力学的关键科学问题。全球著名的大陆造山带中榴辉岩的p-T轨迹呈现差异性折返特征,为了揭示榴辉岩的折返机制,本文结合变质岩石学和地球物理学研究,选取3个典型大陆造山带——中生代—新生代的阿尔卑斯造山带、中生代的苏鲁—大别造山带和新生代的喜马拉雅造山带中的榴辉岩进行阐述。在阿尔卑斯造山带地区,地球物理研究结果发现,欧洲板块的俯冲造成了Adria地区下方的岩石圈存在明显厚度差异。同时,阿尔卑斯造山带Doria Maria和Pohorje地区以及Pohorje地区内部,榴辉岩折返历史也不尽相同,原因可能是亚德里亚大洋岩石圈断离后不同期次的逆冲推覆作用使其差异性斜向挤出。苏鲁—大别造山带中榴辉岩的快速折返,原因可能是华南板块与华北板块碰撞后岩石圈的拆沉或断离作用。在喜马拉雅造山带,西构造结和中喜马拉雅榴辉岩的折返存在差异性。在西构造结,那让和卡甘榴辉岩呈现不同的p-T轨迹和折返速率,变质岩石学和地球物理研究结果都表明它们的差异性折返很可能与印度-欧亚大陆碰撞过程中的构造挤压作用以及印度大陆岩石圈的断离作用有关。喜马拉雅造山带是年轻的正在进行造山活动的造山带,相较于古老的苏鲁-大别造山带,它更适合变质岩石学和地球物理学的综合研究。因此西构造结高压/超高压榴辉岩的折返机制——构造挤压和俯冲板块断离可应用于全球造山带。     

西藏冈底斯地块中新生代中酸性侵入岩特征与构造环境

冈底斯地块上的中新生代中酸性岩浆活动，是北部班公湖一怒江和南部雅鲁藏布两个特提斯演化及其后的陆内汇聚碰撞造山和后造山伸展等大地构造事件的完整记录。地块上的中酸性岩浆活动可划分为三个带，其中北部岩带岩浆岩形成于燕山期，其类型从早期的Ⅰ型到中期的过渡型再演化为晚期的S型，分别形成于板块俯冲-缝合-碰撞等构造条件下，是北部班公湖一怒江特提斯演化的集中反映。中部和南部岩浆岩带则集中体现了南部雅鲁藏布特提斯时空演化的完整经历，其中，南部岩带岩体以燕山晚期为主，喜山早期次之，成因及形成环境与特提斯洋壳向北俯7中作用密切相关(燕山晚期)，同时俯冲结束后的同碰撞条件下的岩浆活动在该岩带内也有明显的反映(喜山早期)；中部岩带岩体以喜山早期为主，燕山晚期次之，岩体大部分为同碰撞环境下岩浆活动的产物，它表征了随着洋壳板块向北俯冲程度的加深和强度的加剧，岩浆活动中心在不断向北迁移，并最终缝合碰撞的过程。因此，该岩带内岩浆岩主要形成于俯冲的晚阶段及缝合后的同碰撞条件下。喜山晚期的小斑岩体实际上广泛出露于整个冈底斯地块上，它反映的是该区在经历了碰撞造山后发生的陆内伸展的构造过程。     

西藏冈底斯地块中新生代中酸性侵入岩浆活动与构造演化

冈底斯地块上的中新生代中酸性岩浆活动,是北部班公湖-怒江和南部雅鲁藏布两个特提斯演化及其后的陆内汇聚碰撞造山和后造山伸展等大地构造事件的完整记录.地块上的中酸性岩浆活动可划分为3个带,其中北部岩带岩浆岩形成于燕山期,其类型从早期的Ⅰ型到中期的过渡型演化为晚期的S型,分别形成于板块俯冲-缝合-碰撞等构造条件下,是北部班公湖-怒江特提斯演化的集中反映.中部和南部岩浆岩带则集中体现了雅鲁藏布特提斯时空演化的完整经历.其中,南部岩带岩体以燕山晚期为主,喜马拉雅早期次之,成因及形成环境与特提斯洋壳向北俯冲作用密切相关(燕山晚期),同时俯冲结束后的同碰撞条件下的岩浆活动在该岩带内也有明显的反映(喜马拉雅早期);中部岩带岩体以喜马拉雅早期为主,燕山晚期次之.岩体大部分为同碰撞环境下岩浆活动的产物,它表征了随着洋壳板块向北俯冲程度的加深和强度的加剧,岩浆活动中心在不断向北迁移,并最终缝合碰撞的过程.因此该岩带内岩浆岩主要形成于俯冲的晚阶段及缝合后的同碰撞条件下.喜马拉雅晚期的小斑岩体实际上广泛出露于整个冈底斯地块上,它反映的是该区在经历了碰撞造山后发生的陆内伸展的构造过程.     

甘孜—理塘断裂带北段构造特征及其演化过程

甘孜-理塘断裂带是义敦造山带与雅江褶皱带的分界断裂。该带由韧性又脆性冲断层、平移断层,以及各种岩块、构造岩片等组合而成。其演化历史主要经历了晚三叠世洋壳的俯冲、晚三叠世末期弧-陆碰撞、陆内会聚和喜马拉雅期断陷的复杂演化过程。     

印度-亚洲碰撞大地构造

印度-亚洲碰撞是新生代地球上最为壮观的重大地质事件.碰撞及碰撞以来,青藏高原的广大地域发生了与碰撞前截然不同的变形,地貌、环境及其深部结构都发生了深刻地变化.根据青藏高原形成、周缘造山带崛起以及大量物质侧向逃逸的基本格局,作者从大陆动力学视角出发,将"印度-亚洲碰撞大地构造" 与"前碰撞大地构造"区别开来进行研究,将印...     

River profiles along the Himalayan arc as indicators of active tectonics

Longitudinal profiles along sixteen major transverse Himalayan rivers add important constraints to models of active continental subduction and its evolution. These profiles are characterized by a zone of relatively high gradient that cannot be associated with differential resistence to erosion in all cases. The base of the zone of increased gradients correlates with (1) the topographic front between the Lesser and High Himalayas, (2) the narrow belt of intermediate-magnitude thrust earthquakes, (3) the Main Central Thrust zone (MCT). These features define a small circle in the central portion of the Himalayan arc. These correlations suggest that the discontinuity in the river profiles and the other features are controlled by a major tectonic boundary between the rising High Himalayas and the Lesser Himalayas. No sharp increases in gradient are observed near the Main Boundary Thrust (MBT), except on a few rivers, such as the Jhelum or Kundar, where the MBT lies close to both the MCT and the seismic belt. Thus, it is unlikely that the MBT is a major tectonic boundary. The diversion of river courses along the MBT and around anticlines in the Sub Himalayas has probably been caused by aggradation near the rosion-deposition boundary, upstream of uplifts in the Mahabharat range and Sub Himalayas.A parallel is drawn between the Himalayas and New Guinea based on the hypothesis that continent-arc collision, of the type occurring in northern Australia, preceded continent-continent collision in the Himalayas. The present sedimentary/tectonic phase in New Guinea resembles the Subathu (Paleocene-Eocene) phase in the Himalayas. Incipient counterparts of the major Himalayan structures, including the MCT and the MBT, are recognized in New Guinea. The drainage patterns in the Himalayas and in New Guinea bear a similar relation to major structures. This suggests that (1) the tectonic evolution of the Himalayas has been rather uniform since early stages of collision, and (2) the Himalayan drainage was also formed at these early stages and is therefore antecedent to the rise of the High Himalayas.     

青藏高原的形成和演化机制

青藏高原是地球上最高大和最雄伟的年青隆起区。对于它的形成和演化机制,一直是国内外地质和地球物理学者注意的问题之一。 近十年来,人们认为青藏高原的形成是由于相距千里之遥的印度板块向北漂移并与欧亚板块碰撞的结果。然而,根据作者对喀喇昆仑和喜马拉雅等地的野外考察及其深部地球物理资料的研究,提出青藏高原原来是一个统一的前震旦纪陆壳区,后经震旦纪以来多次的拉开和挤压碰撞而形成的新观点。这种拉开和挤压的运动方式,是深部鳗隆和慢拗的分异作用引起的。     

POSITIVE INVERSION STRUCTURE OF THE CENTRAL STRUCTURE BELT IN TURPAN-HAMI BASIN

The central structure belt in Turpan-Hami basin is composed of the Huoyanshan structure and Qiketai structure formed in late Triassic-early Jurassic, and is characterized by extensional tectonics. The thickness of strata in the hanging wall of the growth fault is obviously larger than that in the footwall, and a deposition center was evolved in the Taibei sag where the hanging wall of the fault is located. In late Jurassic the collision between Lhasa block and Eurasia continent resulted in the transformation of the Turpan-Hami basin from an extensional structure into a compressional structure, and consequently in the tectonic inversion of the central structure belt of the Turpan-Hami basin from the extensional normal fault in the earlier stage to the compressive thrust fault in the later stage. The Tertiary collision between the Indian plate and the Eurasian plate occurred around 55Ma, and this Himalayan orogenic event has played a profound role in shaping the Tianshan area, only the effect of the collision to this area was delayed since it culminated here approximately in late Oligocene-early Miocene. The central structure belt was strongly deformed and thrusted above the ground as a result of this tectonic event.     

Himalayan Tectonic Evolution in the East Asian Peri-Pacific Region

This paper summarizes the Late Palaeozoic. Indosinian and Yanshanian palaeotectonic settings in theperi-Pacific region of East Asia. On that basis, the Himalayan crustal movement in the region is divided intothe early and late tectonic stages and two principal tectonic phases. From the ocean to the continent, 5 giganticHimalayan formation-deformation belts are distinguished; they are the Northwest Pacific trench-island arcbelt. the Northwest Pacific marginal sea basin bell. the East China Sea-northern South China Seacontinental-shelf down-faulted belt. the East Asian epicontinental rift belt. and the East Asian intracontinentalrift belt. The Early and Late Himalayan tectonic evolution is dealt with. Finally the state of the Himalayan re-gional stress field and its evoution in the region are discussed. It is considered that the mechanism of their for-mation is closely related to the continent-ocean and surface-deep earth interaction.     

Electromagnetic signatures of collision zones in India

Indian subcontinent has experienced intense tectonic activity within the continent in the form of subduction, continent-continent collision, subduction-collision-accretion tectonics. Deep electrical signatures of intense tectonic activity are presented for three different regions: Himalayan region, Central Indian Tectonic zone and Southern Granulite terrain. Two long traverses at each region are discussed along with other geophysical data. The geoelectric sections across the Himalayan region have shown a clear northward dipping signature of the anomalous conductive features at upper to mid-crustal depths. This model gave a clear evidence for the collision and subduction processes. The profiles across the Central Indian tectonic zone constituting major east-west trending faults and mobile belts provided the evidence for the presence of mantle derived fluids at mid-crustal depths and also gave a clear evidence for the collision processes between the Bundelkhand craton and the Dharwar craton. The collision-accretion tectonic process is observed in Southern Granulite terrain of south India. Evidence for the exhumation of mantle derived fluids to the midcrustal depths has been observed along the Vattalakundu-Kanyakumari profile, while the subduction-collision-accretion processes have been observed along Kolattur-Palani geotransect. In all the three tectonically active regions, the deep electrical structure mapped from magnetotellurics, gave a clear evidence for the presence of anomalous conductive structures that can be related to active tectonic regime that has paved a way for better understanding of the evolution of the deep crust. In this paper all the earlier works in three regions with emphasis on tectonics are briefly reviewed.     

特提斯喜马拉雅多重基性岩浆事件：追溯新特提斯洋的生存时限

Processes accompanied the breakup of continents, spreading of ocean floor and continent-ocean transi-tion could trigger large scale melting of the mantle beneath the continent as well as the ocean, and pro-duce mafic magmas with distinct geochemical charac-teristics. Such rocks provide us an important record for unraveling the nature and the time of deep tectonic and magmatic processes during the tectonic evolution of large-scale orogenic belts, such as the Himalayan orogenic belt. As an integrated part of the Himalaya, the Tethyan Himalaya consists of well-developed early Paleozoic to Cenozoic sediments and is noted for de-velopment of spectacular semi-continuous, thousand kilometers long gneiss (or granitic) domes. It has pre-served critical records to address the nature of defor-mation, magmatism, and metamorphism associated with the opening, spreading, and demise of the Neo-Tethyan Ocean and the final continental collision between the Indian and the Eurasian Plate at the early Cenozoic time. In addition, it also could be a type-example to address a number of first-order issues with regard to the tectonic dynamics of passive conti-nental margin during the Wilson-cycle.     

Tectonic Evolution of the Middle Frontal Area of the Longmen Mountain Thrust Belt, Western Sichuan Basin, China

By analyzing the balanced cross sections and subsidence history of the Longmen Mountain thrust belt,China,we concluded that it had experienced five tectonic stages:(1)the formation stage (T3x) of the miniature of Longmen Mountain, early Indosinian movement, and Anxian tectonic movement created the Longmen Mountain;(2)the stable tectonic stage(J1)where weaker tectonic movement resulted in the Longmen Mountain thrust belt being slightly uplifted and slightly subsiding the foreland basin;(3)the intense tectonic stage(J2-3),namely the early Yanshan movement;(4) continuous tectonic movement(K-E),namely the late Yaushan movement and early Himalayan movement;and(5)the formation of Longrnen Mountain(N-Q),namely the late Himalayan movement. During those tectonic deformation stages, the Anxian movement and Himalayan movement played important roles in the Longmen Mountain'S formation.The Himalayan movement affected Longmen Mountain the most;the strata thrust intensively and were eroded severely.There are some klippes in the middle part of the Longmen Mountain thrust belt because a few nappes were pushed southeastward in later tectonic deformation.     

造山带沉积盆地与大陆动力学

造山带原型盆地恢复是地质学研究的重要内容,是板块构造研究的难点与前沿,对于理解造山带演化及其大陆动力学具有重要意义.本文从原型盆地恢复的方法出发,评述了前人根据碎屑组成、元素地球化学和碎屑单矿物年代学来进行原型盆地恢复的原理、方法和效果.基于喜马拉雅造山带沉积盆地的实践,提出造山带原型盆地恢复的五个要素:盆地顶底界面、...     

云南哀牢山地区构造岩石地层单元及其构造演化

依据新获得的同位素年代学资料和构造岩石地层单元,重新认识了云南哀牢山造山带形成与演化历史。认为:在哀牢山地区元古界深变质岩系属基底构造层;前造山期岩石组合及构造演化为扬子地块西缘被动大陆边缘志留纪深水相碎屑岩→陆缘泥盆纪被动裂谷盆地中火山-沉积岩→石炭纪哀牢山有限洋盆及蛇绿岩石组合→晚二叠世-早三叠世哀牢山洋-陆碰撞成陆及弧火山岩-陆相碎屑岩组合。燕山期主造山期及岩石组合为晚三叠世-侏罗纪前陆盆地磨拉石建造-同造山期中酸性侵入岩-燕山期脆韧性剪切带及构造岩。喜马拉雅山期陆内造山成原的岩石组合为第三-第四纪陆内山间盆地中磨拉石建造-红河韧性剪切带及构造岩-富碱侵入岩和煌斑岩。