阿尔金断裂带最大累积走滑位移量——900km？   总被引：13，自引：1，他引：13  

李海兵许志琴  杨经绥戚学祥 P. Tapponnier 《地质通报》2007,26(10):1288-1298

通过变形构造几何学、岩石学和区域构造对比研究,认为阿尔金断裂西北侧的阿尔金山北缘、南缘近EW走向的蓝片岩-榴辉岩高压变质带、榴辉岩超高压变质带分别与阿尔金断裂东南侧的北祁连山、柴北缘NW—SE/NWW—SEE走向的蓝片岩-榴辉岩高压变质带、榴辉岩超高压变质带相对应,并且,高压变质带与超高压变质带的宽度和走向在断裂两侧存在较大的变化。这种在断裂带中宽度变窄、角度趋于与断裂带走向一致的变化是韧性或韧脆性走滑过程中产生的拖曳构造。因此,阿尔金断裂带走滑过程中存在较大的韧性变形,它的最大累积走滑位移量应由韧性和脆性走滑位移量组成,至少大于500km,小于1000km。另外,拖曳构造的几何特征,以及西昆仑库地北蛇绿岩、阿尔金南缘蛇绿岩和柴北缘蛇绿岩在年龄、岩石组合及地球化学特征方面均具有相似之处,暗示在早古生代时期西昆仑和阿尔金南缘、柴北缘很可能处于相同的构造背景之中,后被阿尔金断裂所切割。因此,综合得出了阿尔金断裂带最大累积左旋走滑位移量为900～1000km。  相似文献   

阿尔金南缘构造带西段早古生代绿片岩的地球化学特征及构造环境   总被引：8，自引：1，他引：8       下载免费PDF全文

覃小锋  夏斌 李江 陆济璞许 华周府生胡贵昂李 乾 《中国地质》2007,34(5):799-807

阿尔金南缘构造带西段混杂岩伴生有大量较为新鲜的绿片岩构造岩块。对绿片岩的岩石学和地球化学的详细研究表明,其原岩属于基性火山岩类(拉斑玄武岩类),并存在洋岛(板内)型(OIB)、洋中脊型(E-MORB)和火山弧型(IAT)三类玄武岩。E-MORB型具有大体类似的地球化学性质,它们的TiO2含量均较低,为0.93%～1.75%,平均1.34%;P2O5含量为0.09%～0.15%,平均0.13%;高场强元素Zr为79×10-6～146×10-6,Hf为2.6×10-6～3.5×10-6,Nb为6.6×10-6～15.3×10-6,轻稀土呈亏损-略富集型,具洋中脊玄武岩特征。IAT型TiO2含量比E-MORB型更低,为0.4%,P2O5为0.08%;高场强元素Zr为56×10-6,Hf为1.6×10-6,Nb为5.9×10-6,轻稀土呈略富集型,具岛弧型玄武岩特征。而OIB型均富集TiO2,含量为1.96%～3.08%,平均2.49%;P2O5为0.23%～0.34%,平均值0.26%;高场强元素Zr为204×10-6～237×10-6,Hf为4.2×10-6～7.2×10-6,Nb为14.6×10-6～22.1×10-6,轻稀土呈富集型,具洋岛(板内)玄武岩特征。OIB、E-MORB和IAT组合的出现说明在早古生代阿尔金南缘可能存在过洋盆。  相似文献   

阿尔金西段侏罗系沉积特征及石油地质条件分析     

李伟民  刘永江  马达德  汪立群  薛建勤  刘冬 《世界地质》2015,34(3):704-715

阿尔金西段侏罗系由中、下侏罗统大煤沟组和上侏罗统采石岭组组成,出露于格斯沟至黑水沟一带以及祁曼塔格西北缘,呈NEE方向展布。钻井和地震资料表明,阿尔金西段侏罗系在盆地内部新生界覆盖之下也有大面积分布。大煤沟组是以冲积扇-河流-滨湖相沉积为主的含煤建造,暗色泥岩发育;采石岭组是以洪-冲积扇相沉积为特征的碎屑岩建造。其沉积特征与柴达木盆地北缘、西部以及塔里木盆地极为相似,表明侏罗系沉积时柴达木盆地与塔里木盆地是连通的,属于同一侏罗纪原型盆地,此时阿尔金断裂并不存在。直至渐新世伴随阿尔金断裂的大规模走滑,阿尔金山快速隆升,才分割为两个盆地。有机质化学分析表明大煤沟组中暗色泥岩有机质丰度高,为中等-好的烃源岩,干酪根类型为II2-III型,热演化处于成熟-高熟阶段,具有生油潜力。此外该区域生储盖匹配良好,圈闭发育,具有较好的石油地质条件和油气勘探前景。  相似文献   

阿尔金北缘尧勒萨依花岗岩的成因及构造意义:锆石U-Pb年龄和地球化学制约     

何鹏  杨潘  芦西战  杨睿娜  贺晓天  李福斌  张焕  杨毅明 《地质科学》2022,57(1):230-242

尧勒萨依花岗岩出露于阿尔金北缘西段尧勒萨依河下游至河口一带,岩性为黑云二长花岗岩。为确定尧勒萨依花岗岩形成时代、成因和构造环境,本文从岩石学、锆石U-Pb年代学和地球化学方面进行研究。通过LA-ICP-MS锆石U-Pb定年,显示年龄为240±2 Ma,形成时代为中生代早期晚三叠世。其高硅(SiO;=69.68%~70.64%)、富碱(Na;O+K;O)=9.61%~9.87%,里特曼指数σ=3.34~3.63,呈碱性;铝饱和指数(A/CNK)=0.73~0.80,属准铝质;大离子亲石元素U、Th、K、Rb等相对富集,高场强元素Ti、P、Ta、Nb等相对亏损;稀土含量较高,相对富集轻稀土且分馏明显,(La/Yb);=79.80~88.40,Eu弱亏损(δEu=0.79~0.85)。根据岩体成因类型及区域构造演化特征,认为尧勒萨依花岗岩为壳幔混合的Ⅰ型花岗岩,形成于阿尔金断裂走滑局部应力释放的伸展环境。  相似文献   

2014年于田Ms73地震地表破裂特征及其发震构造   总被引：2，自引：0，他引：2  

李海兵  潘家伟  孙知明  刘栋梁  张佳佳  李成龙  刘亢  CHEVALIER Marie-Luce  云锟  龚正 《地质学报》2015,89(1):180-194

2014年2月12日在新疆于田县境内西昆仑山东段地区发生了Ms7.3级强烈地震,震后野外考察表明,这次地震在海拔4600~5100m的地区形成了由一系列张裂隙、张剪裂隙、剪切裂隙以及挤压鼓包和裂陷等雁行状组合而成的地表破裂带,破裂带沿阿尔金断裂带西南段的两条近平行的分支断裂阿什库勒-硝尔库勒断裂和南硝尔库勒断裂分布,整体呈NEE走向,全长约28km,其中,沿阿什库勒-硝尔库勒断裂展布的地表破裂带长约10km,主要呈N63°~65°E走向,以左旋走滑伴随伸展性质的破裂为主,最大左旋位移约0.7m,最大垂直位移约0.4m;沿南硝尔库勒断裂展布的地表破裂带长约15km,呈N54°~60°E走向,以左旋走滑伴随逆冲性质的破裂为主,最大左旋位移约1m,最大垂直位移约0.75m;上述两破裂带之间沿N15°E方向由零星的张裂隙和右阶雁行状分布的张裂隙或张剪裂隙组成的不连续破裂带长约5km,显示为伸展具有左旋走滑的性质;另外,在南硝尔库勒断裂北侧沿N100°~110°E方向展布一系列具有挤压、右旋走滑性质的地表破裂带长约4km,宽约2km,与NEE走向的左旋走滑破裂带构成同震共轭破裂带。这种特殊的地表破裂样式是近期发生的强地震中结构最复杂的走滑断层型地表破裂。发震断裂属于阿尔金断裂带西南段尾端分支断裂,它与郭扎错断裂和龙木错断裂构成"阿尔金断裂"向SW方向的延伸部分,它们是青藏高原西部晚新生代强烈活动断裂,其大地震活动是由于印度和欧亚板块间碰撞而产生大陆变形的应变能释放过程。  相似文献   

Relationship between the Altyn Tagh strike-slip fault and the Qaidam Basin：New insights from superposed buckle folding in Hongsanhan     

Wei Du  Daowei Zhang  Xiangjiang Yu  Xiang Cheng  Zhendong Wang  Qing Bian 《International Geology Review》2020,62(12):1570-1580

ABSTRACT

The relationship between the sinistral strike-slip Altyn Tagh Fault (ATF) and the internal tectonic deformation of the Qaidam Basin remains a controversial issue. Uncovering the relationship between the structures along the southern slope of the ATF is a viable solution to this problem. The ‘snake-like’ Hongsanhan superposed fold is located on the southern slope of the ATF. The Hongsanhan structure is controlled by the superposition of two generations of folds. The first-generation NW–SE-trending f₁ fold, which developed during the Oligocene, constitutes the principal component of the present-day Hongsanhan fold, while the second-generation NE–SW-trending f₂ folds formed during the middle Miocene. The structure of the Hongsanhan superposed fold proves that the large-scale sinistral strike-slip movements along the ATF began during the Oligocene. In addition, a flower structure associated with the ATF continuously extends into the Qaidam Basin.  相似文献   

2014年2月12日新疆于田M_S7.3级地震主震及余震序列重定位研究          下载免费PDF全文

张广伟  雷建设  孙长青 《地球物理学报》2014,57(3):1012-1020

本研究采用基于贝叶斯理论的绝对定位方法对2014年2月12日新疆于田M_S7.3级地震进行绝对定位,得到震中位置为82.56°E、36.04°N、震源深度为12.3 km;采用双差定位法对254个地震序列进行相对定位,得到101个重定位事件.结果显示,主震位于阿尔金断裂带西南端多个分支断裂的交汇处.余震震源主要分布范围在5~10 km深度之间,主震处余震代表的断层面较为陡立,且余震序列呈现出明显的西南向纯单侧扩展模式.沿阿尔金断裂带主震的北东向民丰震区本次地震后显示一个明显的地震丛集,说明本次主震对该震区具有触发作用.  相似文献   

关于阿尔金断裂错动速率研究的综述及其启示     

王阎昭  王敏 《中国地震》2020,36(4):817-826

阿尔金断裂是中国大陆内部一条重要断裂带,对理解青藏高原的隆升演化和大陆构造变形过程均有重要意义,其滑动速率的争议也成为理解这一问题的关键。本文汇总了近年来关于阿尔金断裂滑动速率绝大部分究成果,包含了82°E～99°E范围内来自一般地质学、古地震和大地测量的结果,覆盖了几十年、千年和万年以上的时间尺度和整个阿尔金断裂带,形成对阿尔金断裂带滑动速率的时空变化特征的全面认识,迄今为止的研究结果均支持阿尔金断裂中西段具有（10±3） mm/a的滑动速率,自约93°E向东逐渐衰减,且随时间变化不大,由于测量方法导致的差异可能与一次大地震或地震高发期有关。  相似文献   

Paleoseismologic record of earthquakes along the Wuzunxiaoer section of the Altyn Tagh fault and its implication for cascade rupture behavior     

Yuan  Zhaode  Liu-Zeng  Jing  Zhou  You  Li  Zhigang  Wang  Heng  Yao  Wenqian  Han  Longfei 《中国科学:地球科学(英文版)》2020,63(1):93-107

The Altyn Tagh fault is one of the few great active strike-slip faults in the world. The recurrence characteristics of paleoearthquakes on this fault are still poorly understood due to the lack of paleoseismic records recorded in high-resolution strata. We document a paleoseismic record in a pull-apart basin along the Wuzunxiaoer section of the central Altyn Tagh fault.The high-resolution strata recorded abundant seismic deformations and their sedimentary responses. Four earthquakes are identified based on event evidence in the form of open fissures, thickened strata, angular unconformities, and folds. The occurrence times of the four events were constrained using radiocarbon dating. Event W1 occurred at AD1220–1773, events W2 and W3 occurred between 407 and 215 BC, and event W4 occurred slightly earlier at 1608–1462 BC, indicating clustered recurrence characteristics. A comparison of the earthquake records along the Wuzunxiaoer section with other records along the Xorkoli section suggests that both sections ruptured during the most recent event.  相似文献   

THE MECHANISMS OF ARCUATE STRUCTURES ON THE SOUTH SIDE OF THE ALTYN TAGH FAULT AND THEIR TECTONIC IMPLICATIONS     

LI Bing-shuai  YAN Mao-du  ZHANG Wei-lin  YANG Yong-peng  ZHANG Da-wen  CHEN Yi  GUAN Chong 《地震地质》2019,41(2):300-319

The giant sinistral Altyn Tagh Fault(ATF)is the northern boundary of the Tibetan Plateau. It has been playing important role in adjusting the India-Eurasia collision and the tectonic evolution of the northeastern Tibetan Plateau. Knowledge of the evolution of the ATF can provide comprehensive understanding of the processes and mechanisms of the deformation of the Tibetan Plateau. However, its timing of commencement, amount of displacement and strike-slip rate, as well as the tectonic evolution of the region are still under debate. South of the ATF, there exist a series of oroclinal-like arcuate structures. Knowledge of whether these curved geometries represent original curvatures or the bending of originally straight/aligned geological units has significant tectonic implications for the evolution of the ATF. The Yingxiongling arcuate belt in the western Qaidam Basin and the northern Qaidam marginal thrust belt(NQMTB)north of the Qaidam Basin are the two typical arcuate thrust belts, where the former has a "7-types" structure, and the latter has a reverse "S-type" structure. Successive Cenozoic sediments are well exposed and magnetostratigraphically dated in both belts. Paleomagnetic declination has great advantage to reveal vertical-axis rotations of geological bodies since they become magnetized. Recently conducted paleomagnetic rotation studies in different parts of these two thrust belts revealed detailed Cenozoic rotation patterns and magnitudes of the region. By integrating these paleomagnetic rotation results with regional geometric features and lines of geological evidence, we propose that these two arcuate thrust belts were most likely caused by different rotations in different parts of these curvatures, due to the sinistral strike-slip faulting along the ATF, rather than originally curved ones. The Yingxiongling arcuate belt was shaped by the significant counterclockwise(CCW)rotations of its northwestern half(the Akatengnengshan anticline)near the ATF during~16~11Ma BP, while its southeastern half(the Youshashan anticline)had no significant rotations since at least~20Ma BP. The geometry of the NQMTB was developed firstly by remarkable clockwise rotations of its middle part during~33~14Ma BP, and later possibly CCW rotations of its northwestern part during the Middle to Late Miocene, similar to that of the northwestern part of the Yingxiongling arcuate belt. The characteristics of two-stage strike-slip evolution of the ATF since the Early Oligocene were enriched:1)During the Early Oligocene to mid-Miocene, fast strike-slip faulting along the ATF was proposed to accommodate the eastward extrusion of the northern Tibetan Plateau with its sinistral shear confined to the fault itself. While in the NQMTB and farther east area in the Qilian Shan, its sinistral shear was transferred to the interior of the plateau and was accommodated by deformation of differential crustal shortenings and block rotations in these regions. Thus, the displacement along the ATF west of the NQMTB is larger than that east of the NQMTB. 2)Since the mid-late Miocene, sinistral shear of the ATF was widespread distributed within the northern Tibetan Plateau, instead of concentrated to the fault itself. Its sinistral offsets were partially absorbed by the shortening deformation within the Qaidam Basin and the Qilian Shan, leading the offsets along the ATF decreasing to the east. With the sinistral frictional drag of blocks(the Tarim Basin and the Altyn Tagh Range)on the other side during the second stage evolution of the ATF, a transitional zone south of the ATF was likely developed by remarkable CCW rotations during the Middle to Late Miocene, which is probably confined to east of the Tula syncline. Combining the sinistral offsets along the ATF derived from the paleomagnetic rotations during the Early Oligocene to mid-late Miocene and that by piercing points since the Late Miocene, the post Oligocene strike-slip offsets were constrained as at least~350~430km for the reference in the western Qaidam Basin and~380~460km for the reference in the NQMTB, with an average slip rate of at least~10.6~13.9mm/a. The post Early Oligocene offsets are consistent with the widely accepted offsets of~300~500km obtained by piercing point analyses.  相似文献