鄂尔多斯盆地中生代地层天然裂缝发育特征与构造应力场演化

鄂尔多斯是我国重要的油气盆地,而绝大多数油气储层都会受到天然裂缝的影响。文中通过野外系统观测和室内的统计分析, 详细描述了盆地中生代地层中的天然裂缝发育特征和主要控制因素, 为裂缝性油气藏勘探开发提供基础理论支持。通过研究得知, 盆内中生代地层中主要发育有6组裂缝： E-W向、 ENE-WSW向、 NE-SW向、 N-S向、 NNW-SSE向、 NNE-SSW向。其中E-W向、 ENE-WSW向和NE-SW向为系统裂缝; N-S向、 NNW-SSE向和NNE-SSW向为非系统裂缝。在裂缝组合中, 有两组正交裂缝系统（E-W向和N-S向, ENE-WSW向和NNW-SSE向）, 其中E-W向和N-S向裂缝构成的正交裂缝系统只出露于三叠和侏罗纪地层。同时, 还有两组共轭裂缝（ENE-WSW向和NNE-SSW向, ENE-WSW向和ESE-WNW向）, 其中ENE-WSW向和NNE-SSW向裂缝构成的共轭裂缝出露于整个中生代地层, 而另外一组只出露于上三叠统延长组中。此外, 裂缝间距分析表明： （1）裂缝间距与力学层厚之间的关联性相对较低; （2）E-W向和ENE-WSW向两组系统裂缝的发育强度好于N-S向非系统裂缝组; （3）岩层厚度越小, 对应裂缝密度则越大。（4）除了岩层厚度, 区域应力场对裂缝的发育具有很大的影响。研究区内裂缝主要形成于两期区域应力场： 第一期是晚侏罗世近E-W向的挤压应力场, 由古太平洋板块向欧亚板块的俯冲和碰撞作用所致; 第二期是新生代NE-SW向的挤压应力场, 由印度板块向欧亚板块的俯冲和碰撞作用所致。     

胶莱盆地白垩纪构造演化

胶莱盆地是位于胶东半岛的白垩纪盆地,前人对该盆地的沉积-构造演化进行了相关研究,也取得了重要进展。但是关于盆地初始形成阶段古构造应力场状态还存在一些争论。本文通过对盆地内部断层滑动矢量数据的反演及节理、同沉积断层指示意义分析,将胶莱盆地白垩纪构造演化划分为五个阶段:早白垩世早期NWW-SEE向伸展,控制了莱阳群初始沉积;莱阳群沉积末期近E-W向挤压;早白垩世晚期E-W向伸展,形成了青山群;早白垩世末期NW-SE向挤压;晚白垩世近N-S向至NNE-SSW向伸展,形成了王氏群。大量的野外现象与前人研究成果均与本文得到的盆地初始成盆阶段NWW-SEE向伸展应力场相吻合。NWW-SEE向伸展作用可能是在古太平洋板块向欧亚板块俯冲过程中,古太平洋板块后撤与苏鲁造山带后造山作用的共同作用下发生的,代表胶莱盆地形成初期,受苏鲁造山带造山后期作用的影响;而青山期伸展方向的变化可能指示盆地主要受到古太平洋板块后撤的影响。盆地在白垩纪古构造应力场的作用下,分别受到早白垩世裂谷作用与晚白垩世走滑拉分作用控制,两种作用的叠加使胶莱盆地成为一个复合型盆地。     

桂西北南丹-荔波地区中、新生代构造演化:来自古构造应力场的证据

桂西北南丹-荔波地区是我国重要的锡多金属矿床富集地,近年来油气勘探显示该区亦具有极大的海相页岩气成藏潜力。因此,深入探讨和认识该区中、新生代构造应力场特征及其构造演化是成矿规律研究和页岩气勘探过程中不可或缺的重要环节。本文以南丹-荔波地区广泛发育的褶皱、共轭节理和断层为研究对象,在详细野外观测的基础上,利用叠加褶皱、共轭节理分析以及断层滑动矢量等方法,反演了研究区中、新生代构造应力场变化。构造解析表明,该区中、新生代共经历了四期构造应力场的交替和演化,分别为NNE-SSW 向挤压、NW-SE 向挤压、NEE-SWW 向伸展和近E-W 向挤压。结合区域构造演化特征,推测NNE-SSW 向挤压应力场的形成可能与印支期华南大陆南北边缘与印支/华北板块碰撞闭合有关;NW-SE 向挤压应力场和NEE-SWW 向伸展应力场可能分别对应于燕山早期古太平洋板块向华南大陆之下的俯冲消减以及燕山晚期发生的弧后伸展作用;近E-W 向挤压应力场可能形成于喜山期印度?欧亚板块陆陆碰撞所产生远程效应的构造背景之下。     

鄂尔多斯盆地构造应力场特征及其构造背景

通过大量断层和褶皱的野外观测以及构造形成序列的确定,同时考虑盆地形成演化过程中板块动力学背景,并结合前人的研究成果,开展了鄂尔多斯盆地古构造应力场的研究。研究表明盆地区域主压应力场方向在加里东期呈NNE-SSW向和近SN向,主要是晚奥陶世以来秦岭洋盆向北俯冲并与华北板块碰撞的结果;印支期主要呈NW-SE向和NNE-SSW向、SN向,主要受中特提斯构造动力体系中羌塘地块与欧亚大陆碰撞拼贴产生的远程构造效应影响;燕山期主要呈NW-SE向,主要受古太平洋大陆板块与欧亚大陆板块碰撞远程构造效应影响,盆地西南缘呈NE-SW向;喜马拉雅期呈NNE-SSW向,主要受新特提斯构造动力体系和今太平洋构造动力体系联合作用影响,即今太平洋板块和印度板块与欧亚板块俯冲碰撞有关。     

基于断层滑动数据反演的燕山中西段晚中生代古构造应力场:对华北克拉通破坏峰期应力状态的启示

在燕山中西段晚中生代岩体中的116个观测点中共采集到2 321组断层和破裂面滑动数据,利用Tensor软件进行古构造应力状态反演。将反演结果与区域构造变形及构造演化过程研究结果相结合,发现研究区在侏罗纪末-白垩纪初以来存在5期可识别的构造应力场:(1)晚侏罗世末-早白垩世初近N-S向挤压应力场(D1,148~127 Ma);(2)早白垩世NW-SE向挤压应力场(D2,143~127 Ma);(3)垂向挤压主导的多向水平伸展应力场(D3,120~110 Ma);(4)NE-SW向挤压(D4);(5)E-W向挤压的应力场(D5)。D1和D2可能分别与蒙古-鄂霍茨克洋消减关闭作用的远程构造效应,以及古太平洋板块向欧亚大陆板块下的俯冲作用有关,且这两大构造系统在该时期可能同时作用于燕山地区。D3期应力场可能反映源自壳下深部地幔活动引起的垂向挤压动力作用。D4、D5期应力场相对较弱,其动力学背景尚待今后研究进一步分析。本区古构造应力场研究结果表明,华北克拉通破坏峰期期间,主要的伸展作用并不完全符合西太平洋板块后撤主导的被动伸展裂谷模型,而是表现为深部地幔活动引起的垂向挤压作用主导的水平方向多向伸展。     

福建泉州晚中生代伸展构造变形特征与年代学制约

晚中生代福建沿海地区发育多期与古太平洋板块俯冲有关的岩浆活动和构造变形.福建泉州地区伸展构造变形主要表现为高角度正断层和低角度正断层或拆离断层, 古构造应力场反演指示其形成于NW-SE向伸展环境.锆石U-Pb年代学指示泉州地区发育4期岩浆活动, 分别为晚侏罗世(~155 Ma)、早白垩世中期(130~125 Ma)、早白垩世末期(~109 Ma)以及晚白垩世早期(~100 Ma之后).结合构造变形的切割关系和岩浆岩年代学, 长乐-南澳剪切带左旋韧性走滑形成于130~120 Ma, 而右旋脆性剪切形成于120~100 Ma之间.古太平洋板块向华南大陆之下的俯冲角度变化导致福建沿海地区发育晚中生代造山带.造山作用开始于早白垩世之初, 结束于早白垩世末期, 以大规模NW-SE向伸展构造发育为标志, 其从同造山挤压到后造山伸展的转换发生于~120 Ma.      

福建泉州晚中生代伸展构造变形特征与年代学制约

晚中生代福建沿海地区发育多期与古太平洋板块俯冲有关的岩浆活动和构造变形.福建泉州地区伸展构造变形主要表现为高角度正断层和低角度正断层或拆离断层,古构造应力场反演指示其形成于NW-SE向伸展环境.锆石U-Pb年代学指示泉州地区发育4期岩浆活动,分别为晚侏罗世(~155Ma)、早白垩世中期(130~125Ma)、早白垩世末期(~109Ma)以及晚白垩世早期(~100Ma之后).结合构造变形的切割关系和岩浆岩年代学,长乐-南澳剪切带左旋韧性走滑形成于130~120Ma,而右旋脆性剪切形成于120~100Ma之间.古太平洋板块向华南大陆之下的俯冲角度变化导致福建沿海地区发育晚中生代造山带.造山作用开始于早白垩世之初,结束于早白垩世末期,以大规模NW-SE向伸展构造发育为标志,其从同造山挤压到后造山伸展的转换发生于~120Ma.     

库车坳陷脆性构造序列及其对构造古应力的指示

在对野外脆性构造(主要是节理和断层) 大量观测的基础上, 根据它们与应力的关系, 讨论了库车坳陷白垩纪末期以来的古构造应力时空变化.结果表明, 在库车坳陷脆性构造中, 早期隆升作用形成的主要发育在中生界的NEE-SWW向系统节理被晚期同构造期的在中生界与上第三系均发育的NNW-SSE向和NW-SE向节理切割并改造, 这是对区域上构造应力场在进入新近纪时从弱伸展变化到强烈挤压这一过程的响应.基于断层滑动分析的古应力反演结果显示, 此时盆山边界处以近N-S向伸展应力状态占主导, 而坳陷内部则表现为近N-S向和NW-SE向挤压应力状态.说明在进入新近纪后, 最大主应力(σ₁) 方向从垂向变成水平, 应力场发生了转变.此后的天山快速垂向隆升是库车坳陷北缘和内部应力状态存在差异的原因.      

江南东段地区NE-SW向断裂带断层滑移矢量反演及其大地构造意义

华南中-新生代构造演化受太平洋构造域和特提斯洋构造域的联合控制.以江南东段NE-SW向景德镇-歙县剪切带和球川-萧山断裂中发育的脆性断层为研究对象,利用野外交切关系和断层滑移矢量反演方法厘定了7期构造变形序列并反演了各期古构造应力场,讨论了断层活动的时代及其动力学.白垩纪至新生代研究区7期古构造应力场分别为:(1)早白垩世早期(136～125Ma)NW-SE向伸展;(2)早白垩世晚期(125～107Ma)N-S向挤压和E-W向伸展;(3)早白垩世末期至晚白垩世早期(105～86Ma)NW-SE向伸展;(4)白垩世中期(86～80Ma)NW-SE向挤压和NE-SW向伸展;(5)晚白垩世晚期至始新世末期(80～36Ma)N-S向伸展;(6)始新世末期至渐新世早期(36～30Ma)NE-SW向挤压和NW-SE向伸展;(7)渐新世早期至中新世中期(30～17Ma)NE-SW向伸展.结合区域地质研究表明,第1期至第4期古构造应力场与古太平洋构造域的板片后撤、俯冲以及微块体(菲律宾地块)间的碰撞作用有关;第5期伸展作用受控于新特提斯构造域俯冲板片后撤,而第6期和第7期古构造应力场主要与印-亚碰撞的远程效应有关.白垩纪至新生代,华南东部受伸展构造体制和走滑构造体制的交替控制.先存断裂的发育可能是导致华南晚中生代走滑构造体制的主要控制因素.     

基于断层滑动矢量应力反演的燕山中段中侏罗世–早白垩世构造应力场序列

燕山板内造山带中段承德一带地层记录齐全且构造变形复杂。该区域主要构造形迹及其运动学特征已经得到了比较系统的研究,但有关形成这些构造形迹的古构造应力场及其演变过程的研究鲜有报道。本文根据断层滑动矢量应力反演理论和方法,通过露头与区域尺度断层运动学数据的搜集与处理,结合研究区域构造层划分特征及主要岩石地层单位的年代学资料,对研究区中侏罗世–早白垩世的构造应力场演变过程进行了研究。经过对擦痕数据进行应力反演并综合分析,共划分出3期5阶段应力场:中侏罗世下花园组沉积之后–髫髻山组火山活动之前的NNW向挤压(D1)(约173~165 Ma);晚侏罗世土城子组沉积中–晚期N-S向挤压(D2-1)(约152~139 Ma);早白垩世初土城子组沉积期末NNE-NE向挤压(D2-2)(约139~135 Ma);以及早白垩世张家口组火山喷发之后垂向挤压主导的多向伸展(D3-1)和NW-NNW向弱挤压(D3-2)(约125 Ma之后)。其中,中–晚侏罗世至早白垩世初以挤压为主,最大主压应力方向发生了大约60°的顺时针旋转,且土城子组沉积作用发生于此挤压作用为主的构造背景之下。早白垩世以伸展为主,并有弱挤压作用出现。同时,研究区内未发现与中侏罗世以来古太平洋板块或伊佐奈岐(Izanagi)板块俯冲作用相关的近W-E向或NW-SE向挤压应力场的存在,可能与克拉通内部变形不均匀有关。     

En echelon fractures in a dextral shear zone - tectonic heritage for a hydrothermal cave (Budapest, Hungary)

Microtectonic study of brittle structures in the József Hill Cave, Budapest, highlights the connection between different phases of fracturing and cave formation. E-W trending dextral faults (second order Riedels) and NW-SE oriented tension fractures developed in a ENE-WSW trending dextral shear zone as a result of WNW-ESE directed compression. Ascending thermal water dissolved cave galleries and created barite veins along these fractures. The first stage of cave formation as inferred from timing of fracturation from the regional stress field was Oligocene-Early Miocene. Between the Middle Miocene and Quaternary new N-S to NE-SW trending normal faults were formed by ESE-WNW extension. Pleistocene differential uplift resulted in the reactivation and enlarging of fault zones, dominantly the E-W trending older Riedels. These recent tectonic events enhanced the original en echelon geometry of the older cave corridors.     

银根-额济纳旗盆地西缘的中-新生代伸展构造

银根-额济纳旗盆地简称银额盆地,是中亚造山带南缘的一个中-新生代沉积盆地。最近的野外地质调查,在其西缘发现早侏罗世和第四纪晚期的伸展构造。早侏罗世的伸展构造为一系列走向NNW-SSE 的正断层,是下侏罗统的同沉积断层。这组正断层与银额盆地内NNE-SSW 走向的正断层组合成共轭断裂系统,指示古构造应力场的最大主拉张应力方向为近E-W。它们是中亚造山带（南缘）造山后应力伸展阶段的构造变形。第四纪晚期的伸展构造是由两条倾向相向的正断层组合成的地堑构造,走向进E-W,可能代表了喜马拉雅碰撞造山远程效应脉动式演化过程的一个构造间歇期。     

Analysis of lineaments within the Wajid Group,SW Saudi Arabia,and their tectonic significance

The Wajid Group is a Cambro-Permian sedimentary succession in southwest Saudi Arabia. This group is a well-known groundwater aquifer in the Wadi Al-Dawasir and Najran areas. The group also represents siliciclastic hydrocarbon reservoirs in the Rub' Al-Khali Basin. The Wajid Group is exposed in an area extending from Wadi Al-Dawasir southward to Najran city. This study aims to map and characterize the lineament traces of the Wajid Group outcrops. Landsat-8 OLI/TIRS satellite images with 30-m resolution, Spot-5 satellite images with 2.5-m resolution and SRTM digital elevation models (DEM) with 30-m resolution were used for lineament trace detection. Those lineament traces supplemented by aeromagnetic lineaments detected from reduced to pole magnetic anomaly map of the studied outcrop. Multi-scale lineament trace maps were generated, and the lineament datasets, including orientation and length, were analyzed statistically. Eight lineament trace trends were identified including NW-SE, NNW-SSE, N-S, NNE-SSW, NE-SW, ENE-WSW, E-W, and WNW-ESE. The northerly, northwesterly, and northeasterly trending lineament traces are predominant. The lineament trace lengths are generally followed the power law distribution. The lineament trace trends were validated through field investigation of the Wajid Group outcrop. The reported outcrop fracture trends are consistent with major lineament trace trends. Lineaments within the Wajid Group outcrop are also consistent with those of the southern portion of the Arabian Shield. The results of this study provide insight into the tectonic origin of the Wajid Group outcrop lineaments, and understanding of the lineaments distribution which can help to predict the fluid flow behavior within the groundwater fractured aquifers or hydrocarbon fractured reservoirs in Rub’ Al-Khali Basin.     

论鄂尔多斯盆地及其周缘侏罗纪变形

侏罗纪是东亚大地构造发展的重要转折时期,在鄂尔多斯盆地及其周缘可划分为两个性质不同的构造变形阶段。早中侏罗世,盆地处于弱引张应力环境,引张方向近N-S至NNE-SSW向,伸展变形主要发生在盆地周边地带,其发生与晚三叠世华南-华北地块沿秦岭造山带碰撞后的陆内应力场调整作用有关。中晚侏罗世,盆地遭受多向挤压应力作用,挤压方向近W-E、NW-SE和NE-SW,在盆地周缘形成展布方向不一、构造样式不同的边界挤压构造带,盆地轮廓基本定型。西缘近N-S向逆冲-推覆构造带的形成与阿拉善地块和陇西地块向东挤出作用有关;东缘及东南缘总体呈“S”形展布的挤压边界带表现为反向逆冲断裂及其相关褶皱,推测发生在山西台褶带深部滑脱系统的前锋上盘断坡。盆地北侧大青山地区近东西向大型推覆构造和早中侏罗世伸展断陷盆地构造挤压反转,表明阴山造山带在中晚侏罗世时期强烈的N-S向缩短变形和再生造山。鄂尔多斯盆地周缘边界构造带记录了中晚侏罗世强烈的陆内多向内挤压作用和大陆地壳增厚过程,其发生的动力学背景与周邻不同板块(古太平洋、西伯利亚、特提斯)同时向东亚大陆汇聚产生的远程效应有关。中晚侏罗世多向挤压变形加速了鄂尔多斯盆地生烃过程,对多种能源矿产富集和成藏定位产生重要影响。     

Joints as fingerprints of stress in the quaternary carbonate deposits along coastal Saurashtra,Western India

Coastal cliffs and shore platforms are important geomorphic features of coastal areas of Saurashtra. These features are composed of medium to coarse grained carbonate sand and are designated as “Miliolitic limestones” that range in age from Middle to Late Pleistocene. Significant jointing has been observed in the Middle Pleistocene Miliolite Formation as well as in the younger shell limestone that comprises Chaya Formation of Late Pleistocene. Along with NE-SW trend which is the direction of maximum horizontal compressive stress [S_Hmax] for Indian sub-continent, other trends recorded are NNE-SSW, N-S, NW-SE and E-W. When compared with other regional studies, neotectonic episode in Saurashtra peninsula appears to be younger than at least 125ky. The present study on joint sets also indicates that they are important to understand stresses associated with anticlockwise rotation of the Indian plate.     

胶南晚中生代大珠花岗岩岩体的脆性变形机制

在长期变化的构造应力作用下,胶南大珠山花岗岩岩体自早白垩世冷凝冷却以来发生强烈的脆性破裂变形,形成了多样的破裂类型如岩脉、节理和断层。在该岩体冷凝冷却早期侵入的细晶花岗岩脉和稍后形成的N-S向节理组反映出与同期区域构造应力场协调的N-S向挤压作用,而后伴随着揭顶剥蚀,出现了交替变化的构造应力场形成了岩体内主导的NW-NNW向和NE向节理组。整体上,恢复出的岩体内构造应力场发生顺时针方向旋转,最大水平挤压由早期的N-S向偏转为晚期的近E-W向。构造应力场的长期变化、平行节理作用和节理断层化作用造成了研究区复杂的破裂型式和破裂序列。     

Alpine paleostress reconstruction and active faulting in Western Iberia

The study of intraplate tectonics is crucial for understanding the deformation within plates, far from active plate boundaries and associated stress transmission to the plate interiors. This paper examines the tectonic evolution of the Variscan basement at the western margin of the Cenozoic Duero basin. Located east of the Vilariça Fault System in NW Iberia, this intraplate zone is a relatively flat but elevated area with an intense NNE-SSW trending fault system and associated moderate seismicity. Although the area has played an important role in the Duero basin configuration, its Alpine to present-day tectonic evolution has not been well constrained. In order to characterize the successive paleostress fields, 1428 pairs of fault-striae were measured at 56 sites and two focal mechanisms were used. Stress inversion methods have been applied to analyze paleostress regimes. Results show the existence of three dominant maximum horizontal stress (Shmax) trends: N-S, NE-SW and E-W. Relative and absolute dating of the activated faults for each Shmax shows that the clearly predominant N-S paleostress field in the zone has been active since the Oligocene up to the present day; while a NE-SW stress field is found to have been active during the Cretaceous and an older E-W paleostress field was active in the earlier Alpine cycle (Late Triassic).     

华南中生代大地构造研究新进展

华南地区中生代构造动力体制经历了从特提斯构造域向滨太平洋构造域的转换,由此产生了强烈的陆内造山作用和岩浆活动,形成了复杂构造组合的晚中生代陆内造山带和火成岩省。本项研究在下列几个方面取得了新的进展:(1)通过对雪峰山地区沅麻盆地的野外调查和构造测量,确定了该盆地晚中生代-早新生代5期构造应力场及其演替序列:中晚侏罗世近W—E向挤压、早白垩世NW—SE向伸展、早白垩世中晚期NW—SE向挤压、晚白垩世近N—S向伸展、古近纪晚期NE—SW向挤压。构造应力场方向的变化记录了不同板缘的动力作用对该区的影响。(2)识别了湖南地区晚古生代-早中生代海相地层中发育的横跨叠加褶皱构造,并基于地层接触关系和已有火成岩同位素年代学数据分析,认为该地区横跨叠加褶皱构造记录了中生代两期构造挤压和地壳增厚事件:早期近东西向褶皱构造是对三叠纪华南地块南北边缘大陆碰撞和增生作用的远程响应,晚期NE—NNE向褶皱构造则是对中晚侏罗世古太平洋板块向华南大陆之下低角度俯冲作用的变形响应。(3)对湖南衡山西缘拆离断裂带的变形结构和运动学特征进行了详细的调查和构造测量,确定了衡山变质核杂岩构造,并对拆离带中韧性剪切变形的钠长岩脉的锆石进行了SHRIMP U-Pb测年,从而确定了华南地区伸展构造的起始时代约137 Ma,即早白垩世早中期。(4)通过锆石U-Pb年代学测试分析,揭示了东南沿海长乐—南澳构造带早白垩世2期构造-岩浆事件:早期(147~135 Ma)表现为强烈的混合岩化作用和深熔作用形成的片麻状花岗岩、花岗片麻岩等;晚期(135~117 Ma)岩浆岩以含石榴子石花岗岩为主。这个结果表明东南沿海构造带是晚中生代陆缘造山带,造山作用可能起始于晚侏罗世,于早白垩世早中期(135 Ma)以来发生伸展垮塌。在上述研究结果的基础上,探讨了华南地区三叠纪"印支运动"和中、晚侏罗世"燕山运动"的表现及其产生的板块构造动力体制及其转换时代、早白垩世从挤压构造应力体制向伸展构造应力体制转变的时间节点。     

Remnants of a Neoproterozoic Collisional Orogenic Belt in the Core of the Phanerozoic Qinling Orogenic Belt (China)

NW-SE trending paleotectonics are recognized from the WNW-ESE trending Qinling complex in the core of the Qinling belt. They consist of trending stratum, boundary shear zones, deformed linear plutons and ophiolite. The field relationships and ages of the deformation, magmatism and metamorphism suggest that the paleotectonics formed in Neoproterozoic. The ages of deformed and undeformed plutons approximately constrain the peak deformation during 958-889 Ma. Both the two trending tectonics constitute an orogen-scale tectonic replacement by S2 (Phanerozoic WNW-ESE tectonics) of S1 (NNW-SSE trending Neoproterozoic), similar to structural replacement in outcrop. The strong contractional deformation, (high-pressure) metamorphism, and granitic magmatism that evolved from syn-collisional (S-type), to post-collisional (I-type) and to post-collisional (A-type), as well as regional extension at 885-700 Ma in Qinling, display a cycle of a collisional orogeny. Thus, the NW-SE trending paleotectonics could be remnants of a collisional orogenic belt. The belt originally could trend NNW-SSE, if reworking and modification of Paleozoic and/or Mesozoic NNE-SSW contractional deformation are eliminated. Accordingly, assemblage and breakup of some continental blocks occurred in Neoproterozoic in Qinling, which seems to correspond to assemblage and breakup of Rodinia supercontinent in the world. This study provides new insight into the evolution of the Qinling orogenic belt and the reconstruction of Proterozoic supercontinent of China, and also presents a case study of recognition of an old orogen from a young orogen.