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1.
甘孜—理塘断裂带构造演化与金矿的关系   总被引:7,自引:0,他引:7  
论述了川西甘孜-理塘断裂带构造演化与金矿床成矿作用的关系,总结了区内金矿化的特征和金矿床类型。研究表明,甘孜-理塘断裂带是由韧性剪切带、逆冲断裂带、断陷盆地带、推覆构造带、脆性破碎带和平移走滑带相互叠加、改造而形成的复杂断裂带。其演化历史主要经历了晚三叠世卡尼期-诺利早期的洋壳俯冲、晚三叠世诺利晚期--瑞替期弧-陆碰撞、侏罗-白垩纪陆内会聚和喜马拉雅期断陷、推覆和平移剪切构造发育演化阶段。区内金矿  相似文献   

2.
班公湖—怒江断裂带东段的构造特征   总被引:2,自引:0,他引:2  
班公湖-怒江断裂带是青藏高原羌塘-唐古拉板块与冈底斯-念青唐古拉板块的缝合带。由韧性推覆剪切带,逆冲断裂带,断陷盆地构造带和推覆构造带,以及蛇绿岩,蛇绿混杂岩,深海复理石,古生代变质岩和燕山期花岗岩侵入体等组合而成,是复杂的断裂系统,主要经历了晚三叠世-中侏罗世洋盆的形成和扩张,晚侏我世洋壳俯冲和岛弧形成,早白垩世-晚白垩世早期弧-陆碰撞汇聚和喜马拉期断陷盆地形成,逆冲推覆构造发育的复杂演化历史过  相似文献   

3.
甘孜—理塘断裂带北段构造特征及其演化过程   总被引:3,自引:0,他引:3  
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。  相似文献   

4.
研究断裂带控制的火山-沉积建造及古生物区系、陆缘岛弧碰撞-造山型花岗岩带、俯冲火山弧根带阿拉斯加型镁铁-超镁铁环状杂岩和造山期或造山期后山前逆冲推覆构造等特征后认为澜沧江断裂带不是冈瓦纳板块与扬子板块的结合带,而是他念他翁山山前与昌都-兰坪-思茅(弧后)前陆盆地之边界断裂。  相似文献   

5.
甘孜-理塘蛇绿混杂岩带作为扬子板块与中咱地块的碰撞结合带,其对探讨西南“三江”多岛弧盆系构造演化具有重要意义。本文选取四川新龙地区瑞环山组进行沉积学、古生物学、地球化学和同位素年代学研究,限定其沉积时代及物质属性,探讨其沉积构造背景。新龙地区瑞环山组为碳酸盐岩夹碎屑岩岩石组合,其碎屑岩物源区为安山质火山岩及陆缘复理石,母岩构造背景为大洋岛弧环境。瑞环山组灰岩中珊瑚化石主要集中于晚侏罗世-早白垩世。碎屑锆石定年结果表明砂岩中锆石主要来源于扬子板块(435Ma、764Ma、1888Ma峰值)以及甘孜-理塘俯冲增生杂岩(229Ma峰值),锆石最新年龄为196±2Ma,指示其应沉积于早侏罗世之后的残留海盆地。研究结果表明,甘孜-理塘洋在晚三叠世末弧陆碰撞造山之后又经历了侏罗纪残留海阶段,在残留海盆地西侧临近甘孜-理塘俯冲增生杂岩浅海环境中沉积了瑞环山组碳酸盐岩夹碎屑岩建造,至早白垩世全面进入造山隆升阶段。  相似文献   

6.
德格—中甸微板块是在晚二叠世初随甘孜—理塘洋的产生而从扬子板块西缘分离出来的。在三叠纪时期受金沙江缝合带与甘孜—理塘缝合带构造作用的相互影响,其沉积构造性质也由被动边缘盆地演化为活动边缘盆地,同时分裂为白玉—义敦前陆盆地,昌台—乡城岛弧带、玉隆—稻城弧前盆地。  相似文献   

7.
雪峰山大地构造的基本特征初探   总被引:18,自引:1,他引:17       下载免费PDF全文
陈海泓  徐树桐 《地质科学》1993,28(3):201-210
雪峰山具有碰撞型造山带的特征。造山作用发生在中生代。根据碰撞造山带的薄壳板块构造模式,可以划分出俯冲壳楔,仰冲壳楔与构造混杂岩三个基本单元。作为俯冲壳楔的杨子板块由前陆盆地与前陆褶冲带所表征,而作为仰冲壳楔的华南板块则以刚性基底推覆体与盖层推覆体所标示,以往称之为板溪群的岩石似应根据其构造特征划分为刚性基底推覆体(具 Smith 地层学意义)和陆壳碰撞作用形成的构造混杂带。  相似文献   

8.
羌塘-三江构造-地层大区的古生代-中生代沉积盆地和构造演化受特提斯洋的控制.通过综合分析前人对羌塘-三江地区大量岩石地层、生物地层、同位素年代学及构造学等研究资料,对羌塘-三江构造-地层大区各分区古生代-中生代的沉积盆地类型进行了划分,并分析了各个沉积盆地的形成和演化过程,探讨了该区的大地构造演化:早古生代该区主体属于大洋环境;晚古生代随着特提斯洋向南东、北东方向的俯冲,该区开始发育一系列活动陆缘沉积盆地,产生金沙江弧后洋、澜沧江弧后洋和甘孜-理塘弧后洋,形成多岛洋弧盆系;中生代,随着特提斯洋向北东的俯冲消减,弧后洋逐渐闭合,羌塘-三江地区发生大规模弧-弧、弧-陆碰撞增生,逐渐转化成陆.随着白垩纪特提斯洋的闭合,印度板块与中国西部碰撞、造山,羌塘-三江地区发育陆内盆地.   相似文献   

9.
桐柏-大别碰撞造山带大型推覆-滑脱构造及其演化   总被引:13,自引:2,他引:13       下载免费PDF全文
桐柏-大别山是从志留至三叠纪连续发展演化的碰撞型造山带,以大规模推覆-滑脱构 为特征,推覆距离可达140km。造山带可分为超叠陆壳、混杂岩片及俯冲陆壳三个构造单元。地层对比、同位素年龄及变形分析可追溯其演化史:晚元古代泛中国板块解体;志留纪末期,古特提斯洋壳俯冲消减;石炭纪时,扬子与华北板块碰撞,陆间俯冲开始,华北板块推覆到扬子板块北缘之上;三叠纪末,形成前陆褶冲带;侏罗-白垩纪以来,造山带收缩隆起,伴随岩浆活动,大型走滑断裂及断陷盆地。  相似文献   

10.
秦岭南缘大巴山褶皱-冲断推覆构造的特征   总被引:14,自引:0,他引:14  
董云鹏  查显峰  付明庆  张茜  杨钊  张燕 《地质通报》2008,27(9):1493-1508
秦岭造山带南缘的大巴山巨型逆冲推覆构造主要是在秦岭造山带板块俯冲碰撞造山与中、新生代以来陆内造山过程中长期复合作用形成的。详细的室内外构造研究表明,巴山逆冲推覆构造可以巴山弧形断裂带为界划分为北大巴山逆冲推覆构造和南大巴山逆冲推覆构造。北大巴山自北而南依次由安康-武当推覆体、紫阳-平利推覆体、高桥-镇坪推覆体和高滩推覆体逆冲叠置而成。南大巴山则以镇巴-阳日断裂为界,分为北部的前陆冲断褶皱带和南部的前陆褶皱带。北大巴山主要是印支期碰撞造山作用和燕山期陆内逆冲推覆作用叠加改造的结果,南大巴山则主要是燕山期递进变形过程中的产物。构造变形北强南弱,北以冲断褶皱变形为特征,南以皱褶作用为主;北部褶皱紧闭复杂,向南渐变为宽缓的薄皮构造。逆冲作用在时序上具有由北向南扩展传递的特点。  相似文献   

11.
TECTONIC EVOLUTION OF THE GARZE—LITANG PLATE JUNCTION, WITH PARTICULAR REFERENCE TO THE GOLD DEPOSITS  相似文献   

12.
Due to the political boundaries between the Central European countries, on one hand, and the thick Tertiary cover in the Pannonian Basin, on the other, the eastward continuation of the Alpine and Dinaridic units has been ambiguous and poorly documented. Based on comparative analyses, the aim of the present paper is to define the pre-Tertiary structural units in the junction area of the Alpine, Dinaridic, and Pannonian regions, in the SW part of the Pannonian Basin, and to draw conclusions on the continuation of the Alpine and Dinaridic units. According to diagnostic characteristics of the Periadriatic Lineament system, the Balaton Lineament system may be considered as its direct eastern continuation. North of the Periadriatic–Balaton Lineament system, the Transdanubian Range Unit, due to its pre-Tertiary paleogeographic setting, shows mainly South Alpine facies relations; however, its present structural position is identical to that of the Upper Austroalpine nappes. Between the Periadriatic–Balaton and Zagreb–Zemplin Lineament systems heterogeneous structural units are juxtaposed, forming the Sava Composite Unit. In the northern part of this composite unit non-metamorphosed nappes occur which can be considered the eastern continuation of the South Alpine units. These nappes are overthrust onto Internal Dinaridic units in the Tertiary. The Zagreb–Zemplin (Mid-Hungarian) Lineament separates the Sava Unit from the Tisza Unit showing close affinity to the Tethyan margin of the Eurasian plate during the early stage of the Alpine evolution. Received: 1 June 1999 / Accepted: 14 March 2000  相似文献   

13.
The Brunovistulian terrane represents a microcontinent of enigmatic Proterozoic provenance that was located at the southern margin of Baltica in the early Paleozoic. During the Variscan orogeny, it represented the lower plate at the southern margin of Laurussia, involved in the collision with the Armorican terrane assemblage. In this respect, it resembles the Avalonian terrane in the west and the Istanbul Zone in the east. There is a growing evidence about the presence of a Devonian back-arc at the margin of the Brunovistulian terrane. The early Variscan phase was characterized by the formation of Devonian extensional basins with the within-plate volcanic activity and formation of narrow segments of oceanic crust. The oldest Viséan flysch of the Rheic/Rhenohercynian remnant basin (Protivanov, Andelska Hora and Horní Benesov formations) forms the highest allochthonous units and contains, together with slices of Silurian Bohemian facies, clastic micas from early Paleozoic crystalline rocks that are presumably derived from terranes of Armorican affinity although provenance from an active Brunovistulian margin cannot be fully excluded either. The development of the Moravo–Silesian late Paleozoic basin was terminated by coal-bearing paralic and limnic sediments. The progressive Carboniferous stacking of nappes and their impingement on the Laurussian foreland led to crustal thickening and shortening and a number of distinct deformational and folding events. The postorogenic extension led to the formation of the terminal Carboniferous-early Permian Boskovice Graben located in the eastern part of the Brunovistulian terrane, in front of the crystalline nappes. The highest, allochthonous westernmost flysch units, locally with the basal slices of the Devonian and Silurian rocks thrusted over the Silesicum in the NW part of the Brunovistulian terrane, may share a similar tectonic position with the Giessen–Harz nappes. The Silesicum represents the outermost margin of the Brunovistulian terrane with many features in common with the Northern Phyllite Zone at the Avalonia–Armorica interface in Germany.  相似文献   

14.
The classical concept of the nappe structure of the central Northern Calcareous Alps (NCA) is in contradiction with modern stratigraphic, structural, metamorphic and geochronological data. We first perform a palinspastic restoration for the time before Miocene lateral tectonic extrusion, which shows good continuity of structures, facies and diagenetic/metamorphic zones. We present a new nappe concept, in which the Tirolic unit practically takes the whole area of the central NCA and is divided into three subunits (nappes): Lower and Upper Tirolic subunit, separated by the Upper Jurassic Trattberg Thrust, and the metamorphic Ultra-Tirolic unit. The Hallstatt (Iuvavic) nappe(s) formed the highest unit, but were completely destroyed by erosion after nappe stacking. Remnants of the Hallstatt nappes are only represented by components of up to 1 km in size in Middle/Upper Jurassic radiolaritic wildflysch sediments ("Hallstatt Mélange" belonging to the Tirolic unit). Destruction of the continental margin started in Middle to Upper Jurassic time and prograded from the oceanic side towards the shelf. The original substratum of the external nappes (Bavaric units) of the NCA was largely the Austroalpine crystalline basement, of the internal nappes (Tirolic units) the weakly metamorphosed Palaeozoic sequences (Greywacke Zone and equivalents). Eocene movements caused limited internal deformation in the Tirolic unit.  相似文献   

15.
Abstract

In the Oman mountains, a succession of sedimentary decollement nappes, the Hawasina nappes, is sandwiched between the Samail ophiolite nappe and its underlying melange and the “autochthonous” sequences of the Arabian platform. The sediments of the Hawasina nappes document the Mesozoic evolution of the northeastern Arabian continental margin and the adjacent Tethys Ocean. In earlier paleogeographic reconstructions, based on simple telescoping of the tectonic units, the upper Hawasina nappes represent the distal part and the lower nappes the proximal part of the margin. New stratigraphic data suggest a revision of the paleogeography and a more complex model for nappe emplacement in the central Oman mountains. The lower Hawasina nappes with their Jurassic and Cretaceous base of slope and basin sediments (Hamrat Duru, Wahrah) form the original cover of part of the upper Hawasina nappes. In the latter (Al Ayn, Haliw), Triassic pelagic sediments, locally overlain by massive sandstone successions are preserved. Complete Mesozoic sequences with pelagic Cenomanian sediments as youngest dated elements are found in the highest Hawasina units (Al Aridh and Oman Exotics). The stratigraphic data indicate polyphase thrusting in the central Oman mountains. Downward propagation of thrusting in front of the Samail is responsible for cutting the original stratigraphie sequence into a number of thrust-sheets, involving successively older and more external formations. This kind of thrust propagation eventually leads to the observed superposition of originally lower stratigraphie units onto their original cover. Regional deformation of the nappe contacts in post-nappe culminations (J. Akhdar, Saih Hatat) is related to ramp-flat-systems in the Arabian foreland.  相似文献   

16.
The structure and tectonics of the Aga Zone are considered. It is shown that this zone is a system of tectonic nappes thrust over the Argun microcontinent. The zone is composed of two rock complexes related to the Variscan and Kimmerian structural stages. The Variscan stage (Silurian(?)-Early Carboniferous) comprises structural elements that correspond to the continental slope; the oceanic basin proper; the active continental margin, including an accretionary wedge; and an island arc and backarc basin. The Devonian age of the ophiolites of the Shilka Belt is specified. The formation of this set of tectonic units is related to the Middle Paleozoic pulse of the opening of the Mongolia-Okhotsk paleobasin. The Kimmerian stage (Middle Carboniferous-Early Jurassic) is characterized by a different style of structural evolution. A system of separate troughs filled with flyschoid sequences was formed on the Variscan basement. The unstable setting related to shortening and closure of the paleobasin brought about the spatial migration of sedimentation zones and the development of intraformational breaks in sedimentation, as well as unconformities. This stage was completed in the Lias by the general uplift of the territory and the formation of Jurassic and Cretaceous mollase along its periphery. The Aga allochthonous mass was ultimately formed in the Middle Jurassic. This event is recorded in emplacement of Middle-Late Jurassic granitic plutons that blocked the nappes. The granitic-metamorphic layer was formed in the Paleozoic and Early Mesozoic at the margin of the Aga Zone upon its conjugation with the adjacent continental masses; this layer is related to crustal anatexis. The bulk of the granitic rocks of the Aga Zone were generated in the Middle and Late Jurassic due to the collision of the North Asian continent with the Argun microcontinent.  相似文献   

17.
四川彭县推覆构造的特征与形成   总被引:7,自引:0,他引:7  
本文对前龙门山区彭县推覆构造进行了详细研究,在推覆体内部划分出若干不同的构造带,强烈压缩变形的白水河断裂带为其“根带”。它们主要是旱第三纪末的陆内俯冲挤压导致的褶皱-逆冲作用以及随后的重力滑动作用形成的。推覆体在滑移过程中发生变形,并对原地岩系的构造进行改造。  相似文献   

18.
四川木里梭罗沟金矿床位于甘孜—理塘构造成矿带的南段、唐央复式背斜南东倾伏端(或唐央穹窿南缘),目前已探明储量属大型岩金矿床。矿体产于上三叠统曲嘎寺组蚀变基性火山岩中,受近东西向断裂控制。矿床具多期成矿特点,属构造蚀变岩型—中低温热液型金矿床。  相似文献   

19.
The Austroalpine nappe systems in SE-Switzerland and N-Italy preserve remnants of the Adriatic rifted margin. Based on new maps and cross-sections, we suggest that the complex structure of the Campo, Grosina/Languard, and Bernina nappes is inherited largely from Jurassic rifting. We propose a classification of the Austroalpine domain into Upper, Middle and Lower Austroalpine nappes that is new because it is based primarily on the rift-related Jurassic structure and paleogeography of these nappes. Based on the Alpine structures and pre-Alpine, rift-related geometry of the Lower (Bernina) and Middle (Campo, Grosina/Languard) Austroalpine nappes, we restore these nappes to their original positions along the former margin, as a means of understanding the formation and emplacement of the nappes during initial reactivation of the Alpine Tethyan margin. The Campo and Grosina/Languard nappes can be interpreted as remnants of a former necking zone that comprised pre-rift upper and middle crust. These nappes were juxtaposed with the Mesozoic cover of the Bernina nappe during Jurassic rifting. We find evidence for low-angle detachment faults and extensional allochthons in the Bernina nappe similar to those previously described in the Err nappe and explain their role during subsequent reactivation. Our observations reveal a strong control of rift-related structures during the subsequent Alpine reactivation on all scales of the former distal margin. Two zones of intense deformation, referred to as the Albula-Zebru and Lunghin-Mortirolo movement zones, have been reactivated during Alpine deformation and cannot be described as simple monophase faults or shear zones. We propose a tectonic model for the Austroalpine nappe systems that link inherited, rift-related structures with present-day Alpine structures. In conclusion, we believe that apart from the direct regional implications, the results of this paper are of general interest in understanding the control of rift structures during reactivation of distal-rifted margins.  相似文献   

20.
DEFORMATIONAL AND METAMORPHIC HISTORY OF THE CENTRAL LONGMEN MOUNTAINS, SICHUAN CHINA1 ArneDC ,WorleyBA ,WilsonCJL ,etal.Differentialexhumationinresponsetoepisodicthrustingalongtheeasternmar ginoftheTibetanPlateau[J] .Tectonophysics,1997,2 80 :2 39~ 2 56 . 2 ChenSF ,WilsonCJL ,WorleyBA .TectonictransitionfromtheSongpan GarzeFoldBelttotheSichuanBasin,south westernChina[J] .BasinResearch ,1995,7:2 35~ 2 53. 3 ChenSF ,WilsonCJL .Emplaceme…  相似文献   

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