Structural and Chronological Evidence for the India-Eurasia Collision of the Early Paleocene in the Eastern Himalayan Syntaxis, Namjagbarwa

The eastern Himalayan syntaxis in Namjagbarwa is a high-grade metamorphicterrain formed by the India-Eurasia collision and northward indentation of the Indian continent intoAsia. Right- and left-lateral slip zones were formed by the indentation on the eastern and westernboundaries of the syntaxis respectively. The Dongjug-Mainling fault zone is the main shear zone onthe western boundary. This fault zone is a left-lateral slip belt with a large component ofthrusting. The kinematics of the fault is consistent with the shortening within the syntaxis, andthe slipping history along it represents the indenting process of the syntaxis. The Ar-Archronological study shows that the age of the early deformation in the Dongjug-Mainling fault zoneranges from 62 to 59 Ma. This evidences that the India-Eurasia collision occurred in the earlyPaleocene in the eastern Himalayan syntaxis.

Stress Transfer and the Impact of the India-Eurasia Collision and the Western Pacific Subduction on the Geodynamics of the Asian Continent

The interaction between the India-Eurasia collision and the Western Pacific subduction and their contribution to recent geodynamics of the Asian continent are discussed. We perform a comparative analysis of the data available from world literature and new data on the slow strain and earthquake migration from the India-Eurasia collision and the Western Pacific subduction zones. Based on the concepts of wave dynamics of the deformation processes, a localization scheme is constructed illustrating the migration of slow strain fronts in central and eastern Asia, and the wave geodynamic impact of collision and subduction on the Asian continent is shown.

Structural Relationships along a Neoarchean Arc-Continent Collision Zone, North China Craton

The Archean North China Craton is composed of the Western Block,Eastern Block and the intervening Central Orogenic Belt.A 4-10 km wide and 85 km long tectonic mélange belt informally called the Zanhuang tectonic

Numerical Modeling of Basin-Range Tectonics Related to Continent-Continent Collision

Continent-continent collision is the most important driving mechanism for the occurrence of various geological processes in the continental lithosphere. How to recognize and determine continent-continent collision, especially its four-dimensional temporal-spatial evolution, is a subject that geological communities have long been concerned about and studied. Continent-continent collision is mainly manifested by strong underthrusting (subduction) of the underlying block along an intracontinental subduction zone and continuous obduction (thrusting propagation) of the overlying block along the intracontinental subduction zone, the occurrence of a basin-range tectonic framework in a direction perpendicular to the subduction zone and the flexure and disruption of the Moho. On the basis of numerical modeling, the authors discuss in detail the couplings between various amounts and rates of displacement caused by basin subsidence, mountain uplift and Moho updoming and downflexure during obduction (thrusting propagation) and subduction and the migration pattern of basin centers. They are probably indications or criteria for judgment or determination of continent-continent collision.

On Continent-Continent Point-Collision and Ultrahigh-Pressure Metamorphism

Up to now it is known that almost all ultrahigh-pressure (UHP) metamorphism of non-impact origin occurred in continent-continent collisional orogenic belt, as has been evidenced by many outcrops in the eastern hemisphere. UHP metamorphic rocks are represented by coesite- and diamond-bearing eclogites and eclogite facies metamorphic rocks formed at 650-800℃ and 2.6-3.5 GPa, and most of the protoliths of UHP rocks are volcanic-sedimentary sequences of continental crust. From these it may be deduced that deep subduction of continental crust may have occurred. However, UHP rocks are exposed on the surface or occur near the surface now, which implies that they have been exhumed from great depths. The mechanism of deep subduction of continental crust and subsequent exhumation has been a hot topic of the research on continental dynamics, but there are divergent views. The focus of the dispute is how deep continental crust is subducted so that UHP rocks can be formed and what mechanism causes it to be subducted to great depths and again exhumed to the shallow surface. Through an analysis of the continental process and mechanical boundary conditions of the Dabie collisional belt-an UHP metamorphic belt where the largest area of UHP rocks in the world is exposed, this paper discusses the variations of viscous stresses and average pressure in the viscous fluid caused by tectonism with rock physical properties and the contribution of the tectonic stresses to production of UHP. Calculation indicates that the anomalous stress state on the irregular boundary of a continental block may give rise to stress concentration and accumulation at local places (where the compressional stress may be 5-9 times higher than those in their surroundings). The tectonic stresses may account for 20-35% of the total UHP. So we may infer that the HP (nigh-pressure)-UHP rocks in the Dabie Mountains were formed at depths of 60-80 km. Thus the authors propose a new genetic model of UHP rocks-the point-collision model. This model conforms to the basic principles of the mechanics and also to the geologic records and process in the Dabie orogenic belt. It can explain why UHP rocks do nol exist along the entire length of the collisional orogen but occur in some particular positions. The authors also propose that the eastern and western corners of the Himalaya collision zone are typical point-collision areas and that almost all UHP metamorphism of continental crustal rocks occurred in the two particular positions.

Surface Processes Driving Intracontinental Basin Subsidence in the Context of India–Eurasia Collision:Evidence from Flexural Subsidence Modeling of the Cenozoic Southern Tarim Basin along the West Kunlun Foreland,NW Tibetan Plateau

The India–Eurasia collision has produced a number of Cenozoic deep intracontinental basins,which bear important information for revealing the far-afield responses to the remote collision.Despite their significance,their subsiding mechanism remains the subject of debate,with end-member models attributing it to either orogenic or sedimentary load.In this study,we conduct flexural subsidence modeling with a two-dimensional finite elastic plate model on the Hotan-Mazatagh section along the southern Tarim Basin,which defines a key region in the foreland of the West Kunlun Orogen,along the NW margin of the Tibetan Plateau.The modeling results indicate that the orogenic load of West Kunlun triggers the southern Tarim Basin to subside by up to less than ~6 km,with its impact weakening towards the basin interiors until ~230 km north from the Karakax fault.The sedimentary load,consisting of Cenozoic strata,forces the basin to subside by ~2 to~7 km.In combination with the retreat of the proto-Paratethys Sea and the paleogeographic reorganization of the Tarim Basin,we propose that surface processes,in particular a shift from an exorheic to an endorheic drainage system associated with the consequent thick sedimentary load,played a decisive role in forming deep intracontinental basins in the context of the India-Eurasia collision.

A Paleogeographic and Depositional Model for the Neogene Fluvial Succession, Pishin Belt, Northwest Pakistan: Effect of Post Collisional Tectonics on Sedimentation in a Peripheral Foreland Setting

Detailed facies analysis of the Neogene successions of the Pishin Belt （Katawaz Basin） has enabled documentation of successive depositional systems and paleogeographic settings of the basin formed by the collision of the northwestern continental margin of the Indian Plate and the Afghan Block. During the Early Miocene, subaerial sedimentation started after the final closure of the Katawaz Remnant Ocean. Based on detailed field data, twelve facies were recognized in Neogene successions exposed in the Pishin Belt. These facies were further organized into four facies associations i.e. channels, crevasse splay, natural levee and floodplain facies associations. Facies associations and variations provided ample evidence to recognize a number of fluvial architectural components in the succession e.g., low-sinuosity sandy braided river, mixed-load meandering, high-sinuosity meandering channels, single-story sandstone and/or conglomerate channels, lateral accretion surfaces （point bars） and alluvial fans. Neogene sedimentation in the Pishin Belt was mainly controlled by active tectonism and thrusting in response to the oblique collision of the Indian Plate with the Afghan Block of the Eurasian Plate along the Chaman-Nushki Fault. Post Miocene deformation of these formations successively caused them to contribute as an additional source terrain for the younger formations.

Structural and Geochronological Evidence for Multiple Episodes of Tertiary Deformation along the Ailaoshan-Red River Shear Zone, Southeastern Asia, Since the Paleocene

Structural analyses show that the Ailaoshan-Red River shear zone （ASRRSZ） in Ailao Mountain is composed of three different deformational domains. These domains may represent three episodes of left-lateral slip experienced by the ASRRSZ. The first episode of such deformation occurred throughout the eastern high-grade belt of the ASRRSZ under a transtensional regime and produced L- type tectonites of amphibolite grade. The second episode of left-lateral slip formed high strain zones overprinting the high-grade belt. Its deformational mechanism is similar to simple shear and the deformed rocks are L-S mylonites of greenschist grade. The third episode of left-lateral slip took place chiefly in a western low-grade belt of the ASRRSZ. This deformation occurred in a transpressional regime, formed an overall structure pattern of a sinistral thrust system and produced phyllonites of low-greenschist grade. Geochronological data indicated that the three episodes of left-lateral slip happened before ～58-56 Ma, at least from ～27 Ma to 22 Ma and at ～13-12 Ma respectively. The first episode of slip in the ASRRSZ appeared to correspond to the initial collision of India and Asia at ～60 Ma. The second episode took place almost at the same time as the most intensive compression and uplift in Tibet. The latest event might represent a further eastward material flow in Tibet after ～16-13 Ma. Thus, the ASRRSZ of southeastern Asia probably experienced three main episodes of Tertiary left- lateral slip in the course of intracontinental convergence since the India-Asia collision.

Set methods of left-turn waiting zone at signalized intersection

To maximize the number of vehicles passing by the stop-line in a cycle and improve the operation efficiency of intersection in China, the settlement of left-turn lane waiting-zone is becoming prevailing. Based on conflicting-point method, the internal mechanism of left-turn flow after stopping line was analyzed through taking postposition left-turn lane waiting-zone intersection for instance. The relationship between the first left-turn vehicle and the last vehicle of previous phase passing the conflicting point was expounded. According to the time of successive arriving of two vehicle flows at conflicting-point, the reasonable layout for waiting area of left-turn vehicles was researched when the clearance index was less than O. The results suggest that the appropriate layout for waiting area of left-turning vehicles can improve the operation efficiency of intersections.

基于改进快速行进平方法的无人帆船动态避碰方法

[目的]为解决无人帆船在开阔水域的多船避碰问题,对基于改进快速行进平方(IFMS)法的局部动态避碰算法进行研究。[方法]考虑到帆船的速度不可控,将其避碰行为转化为航向控制问题,并以总势场梯度下降方向为期望避碰航向。当帆船没有碰撞危险或顺风航行时,仅通过构造时间势场来避开所有静止不规则障碍并到达目标点;而当帆船存在航行约束时,根据《国际海上避碰规则》(COLREGS)为特定会遇场景设计高斯似然函数用以动态地构建障碍势场。同时,考虑到帆船的航行死区,引入局部风势场,实现帆船动态避碰与“之”字形航行策略相结合的应用需求。[结果]结果显示,所提算法可以使无人帆船在遵守避碰规则和避免航行死区的同时,成功地在各种会遇场景下实现与其他帆船、受限机动船的避碰操作,相比原始快速行进平方(FMS)算法,逆风航行时间大大缩短,避碰航迹也更加合理、安全。[结论]所提方法符合帆船运动特性及避碰规则,在复杂环境下具有较高的安全性和鲁棒性,对无人帆船自主避障技术发展具有一定的科学价值。

非通航孔桥梁防船撞系统恒阻力装置研究

为给非通航孔桥梁防船撞系统拦截过程提供稳定持续的阻力,提出了一种利用耗能索持续协同大变形和连续破断输出稳定阻力的恒阻力装置。恒阻力装置由主绳、耗能索、破断环及其它连接件组成,与自适应浮筒、拦截网、系泊浮体等装置共同组成非通航孔桥梁自适应恒阻力船舶拦阻系统,有效拦截偏航船舶,保护非通航孔桥梁和来撞船舶的安全。通过理论分析研究该装置的阻力输出特性,建立该装置的阻力输出力学模型与计算方法,并通过拉伸破坏试验验证计算方法的准确性,进一步对影响装置阻力输出的耗能索的初始间距、长度及伸长率进行分析。结果表明:恒阻力装置能够有效地输出稳定且持续的阻力;耗能索初始间距越小,恒阻力装置阻力输出越大,阻力输出越稳定;耗能索长度或伸长率越大,恒阻力装置阻力输出越大,阻力输出越稳定。该装置已应用于力洋港大桥非通航孔区桥梁防撞中,有效地保护了大桥的安全。

基于定位、速度双误差的物流无人机碰撞概率分析

物流无人机(UAV)批量运行会存在一定的碰撞风险,为量化UAV之间在空中的碰撞概率,针对物流UAV空中运行阶段开展建模分析其碰撞风险。基于冲突区域理论,建立定位、速度双误差的UAV碰撞概率模型,分析不同夹角情况下物流UAV碰撞概率变化情况。分析识别美国联邦航空管理局官网中关于民用小型UAV的事故/事件数据中的关键风险因素。结合2万飞行小时的物流UAV故障数据建立UAV安全飞行间隔模型,给出可接受安全水平下的最短飞行间隔。探究在给定飞行间隔前提下不同航迹角以及不同风向对UAV之间碰撞概率的影响。结果表明:当物流UAV之间最短安全间隔大于90.71 m时,所有飞行场景下UAV的风险水平均在可接受范围之内。当航迹角为30、60、90°时,碰撞概率随风向变化的波动范围较小,其中,航迹夹角为90°时最稳定。而当夹角为140°时,碰撞概率的波动范围较大,UAV安全飞行对环境因素更为敏感。

复杂行星表面着陆避障增广曲率制导方法

针对复杂行星表面安全着陆问题,提出避障增广曲率制导方法。在基本曲率制导律的基础上引入障碍规避增广项。该方法利用着陆器着陆空间区域划分的思想,在障碍附近易发生碰撞区域建立膨胀预警区,基于膨胀预警区推导连续解析的障碍规避制导律,在满足几何凸轨迹状态约束的同时,考虑着陆器与障碍的相对位置关系,能够快速引导着陆器远离障碍,提高着陆器着陆过程中的安全性。仿真结果表明,该方法能够有效规避复杂行星表面的地形障碍,实现在行星表面定点软着陆,具有良好的灵活性和可靠性。

晚古生代—早中生代云南德钦白马雪山岩体演化的年代学约束及地球化学特征

为深入理解金沙江构造带的地质演化历史及其时间框架,本研究对江达—德钦—维西岩浆弧西侧的地质现象进行了系统分析,并聚焦于尼侬英云闪长岩和白马雪山花岗闪长岩的成因和时代。高精度的锆石U-Pb年代学结果表明,这两类岩石分别形成于二叠纪早期(279±2.9 Ma)和晚期(255.8±5 Ma),这为金沙江构造带的地质演化提供了新的时间框架。全岩分析表明岩体为高钾钙碱性中酸性侵入岩系列,属准铝质—过铝质岩石,富集大离子亲石元素,强烈亏损高场强元素(Nb、Ta、Ti),为典型的弧岩浆特征。该岩体与加仁及鲁甸闪长岩类岩体地球化学特征相似,岩浆来源相似,但经历了不同的岩浆演化过程。结合已发表数据,本研究表明自古生代以来,金沙江构造带可能经历了至少5期花岗质岩浆事件:347~340 Ma,292~279 Ma,261~249 Ma,237~235 Ma和232~214 Ma;尼侬英云闪长岩(279±2.9 Ma)形成于金沙江古特提洋西向俯冲消减的起始阶段,而白马雪山花岗闪长岩(255.8±1.8 Ma)可能形成于俯冲阶段结束或俯冲向碰撞的转换阶段;金沙江构造带碰撞造山发生在中三叠世而止于晚三叠世中期。这些发现为理解金沙江构造带乃至整个青藏高原东部区域的构造演化和板块动力学过程提供了新的视角和制约。

Anatomy of composition and nature of plate convergence： Insights for alternative thoughts for terminal India-Eurasia collision

The pattern and timing of collision between India and Eurasia have long been a major concern of the international community. However, no consensus has been reached hitherto. To explore and resolve the disagreements in the Himalayan study,in this paper we begin with the methodology and basic principles for the anatomy of composition and nature of convergent margins,then followed by an effort to conduct a similar anatomy for the India-Eurasia collision. One of the most common patterns of plate convergence involves a passive continental margin, an active continental margin and intra-oceanic basins together with accreted terranes in between. The ultimate configuration and location of the terminal suture zone are controlled by the basal surface of the accretionary wedge, which may show fairly complex morphology with Z-shape and fluctuant geometry. One plausible method to determine the terminal suture zone is to dissect the compositions and structures of active continental margins. It requires a focus on various tectonic elements belonging to the upper plate, such as accretionary wedges, high-pressure(HP)-ultra-high-pressure(UHP) metamorphic rocks, Barrovian-type metamorphic rocks and basement nappes, together with superimposed forearc basins.Such geological records can define the extreme limits and the intervening surface separating active margin from the passive one,thus offering a general sketch for the surface trace of the terminal suture zone often with a cryptic feature. Furthermore, the occurrence of the cryptic suture zone in depth may be constrained by geophysical data, which, in combination with outcrop studies of HP-UHP metamorphic rocks, enables us to outline the terminal suture zone. The southern part of the Himalayan orogen records complicated temporal and spatial features, which are hard to be fully explained by the classic "two-plate-one-ocean" template,therefore re-anatomy of the compositions and nature for this region is necessitated. Taking advantage of the methodology and basic principles of plate convergence anatomy and synthesizing previous studies together with our recent research, we may gain new insights into the evolution of the Himalayan orogeny.(1) The Yarlung-Zangbo ophiolite is composed of multiple tectonic units rather than a single terminal suture zone, and a group of different tectonic units were juxtaposed against each other in the backstop of the Gangdese forearc.(2) The Tethyan Himalayan Sequence(THS) contains mélanges with typical block-in-matrix structures, uniform southwards paleocurrents and age spectra of detrital zircons typical of Eurasia continent. All of these facts indicate that the THS belonged to Eurasia plate before the terminal collision, emplaced in the forearc of the Gangdese arc.(3) The Greater Himalayan Crystalline Complex(GHC) and Lesser Himalayan Sequence(LHS) comprise complex components including eclogites emplaced into the GHC and the upper part of the LHS. Judging from the fact that HP-UHP metamorphic rocks are exhumed and emplaced in the upper plate, the GHC and the upper part of the LHS where eclogite occur should be assigned to the upper plate, lying above the terminal subduction zone surface. It is the very surface along which the continuous subduction of the India subcontinent occurred, therefore acting as the terminal, cryptic suture. From the suture further southward, the bulk rock associations of the LHS and Sub-Himalayan Sequence(Siwalik) show little affinity of mélange, probably belonging to the foreland system of the India plate. By the anatomy of tectonic features of all the tectonic units in the Himalayan orogen as well as the ages of the subduction-accretion related deformation, we conclude that the terminal India-Eurasia collision occurred after 14 Ma, the timing of the metamorphism of the eclogites emplaced into the upper plate. The development of rifts stretching in N-S direction in Tibet and tectonic events with the transition from sinistral to dextral movements in shear zones, such as the Ailaoshan fault in East Tibet, can coordinately reflect the scale and geodynamic influence of the India-Eurasia convergence zone.By conducting a detailed anatomy of the southern Himalayas, we propose a new model for the final collision-accretion of the Himalayan orogeny. Our study indicates that the anatomy of structures, composition, and tectonic nature is the key to a better understanding of orogenic belts, which may apply to all the orogenic belts around the world. We also point out that several important issues regarding the detailed anatomy of the structures, compositions and tectonic nature of the Himalayan orogeny in future.

基于DEM的球磨机内介质碰撞特征研究

针对某铅锌矿选厂球磨机排矿粒度指标不理想,通过破碎统计力学进行介质配比优化,得到球磨机介质推荐补加方案Φ120 mm:Φ100 mm:Φ90 mm=50∶20∶30。使用Solidworks建立具有代表性的球磨机筒体,基于离散元方法,对现场及推荐介质配比进行仿真模拟研究。引入了惰性区面积作为评价磨矿介质方案合理的指标之一,将球磨机内惰性区域面积进行对比,得出优化后的推荐方案介质配比流动性较现场方案有一定提升,惰性区面积有所减小。将介质群运动状态、速度分布特征进行对比分析,中介质群循环中心坐标向右上方由(22.8,9.8)偏移到(24,12),表明推荐方案增加了磨机内的相对速度。通过引入不同尺寸矿石的断裂能以及数值模拟磨机内碰撞能量分析得出,大颗粒矿石的一次破碎次数基本为零,粗颗粒破碎是以研磨为主导的疲劳破碎,细颗粒破碎主要是冲击破碎。通过离散元方法模拟验证了推荐方案在各方面优于现场方案,提高了球磨机内的有效研磨面积,提高了能量的利用率,降低了能耗,证明了推荐方案优于现场方案,研究结果为选厂球磨机介质配比的优化提供了参考和指导。

智能防疫消杀机器人安全性及有效性研究

目的探究消杀机器人安全性和有效性的研究方法,为消杀机器人评价方法的建立提供依据。方法通过调整障碍位置并固定推拉力计,测试消杀机器人的可识别障碍范围、盲区位置、物理碰撞力度,分析消杀机器人移动安全性;利用电气安全分析仪和耐压仪,分析消杀机器人电气安全性;利用粒度分析仪测试消杀机器人的超声雾化量、粒径分布,并根据《消毒技术规范》对物体表面的喷雾消杀效果进行评价。结果消杀机器人的3种避障方式对不同高度障碍物的识别能力差别大,且存在多个盲区,物理触边传感器可有效地对其盲区内的碰撞进行防护;消杀机器人可触及电压电流和介电强度符合GB 4793.1-2007的要求;消杀机器人的平均雾化粒径值<5μm,消杀效果受相对位置影响较大,对于与消杀机器人喷雾出口等高的物体表面消杀效果好,对较低的物体表面的消杀效果不理想。结论本文提出的安全有效性研究方法是可行的,可为建立消杀机器人评价方法提供依据。

印度-欧亚侧向碰撞带构造-岩浆演化的动力学背景与过程——以藏东三江地区构造演化为例

对于印度与欧亚板块的侧向碰撞带,即藏东三江地区的新生代构造分析揭示出三种不同性质的构造样式,它们形成于不同的地质时期,发育于不同的地壳层次:(1)区域规模至露头尺度上发育的具有薄皮属性的逆冲断层与推覆构造,它们广泛分布于三江地区,尤其是兰坪-思茅盆地内;(2)以红河-哀牢山断裂、澜沧江和怒江-高黎贡山断裂等为代表的区域高温型走滑韧性剪切带构造和局部发育的脆性走滑断裂构造,后者在中新生代盆地内部断裂更为发育;(3)遍布全区发育的变质核杂岩构造与地堑-半地堑盆地。区域岩浆活动性与区域构造事件的发生具有密切的时空联系。区域性递进收缩事件与走滑事件发生于碰撞过程的早期阶段,并随后伴随着早期具有岩石圈板块俯冲性质的碰撞弧高钾岩浆活动,而后期的递进伸展事件诱发了板内伸展环境中的晚期高钾岩浆活动。二者之间的碱性岩浆活动间歇期,对应着区域构造体制的转变与区域伸展作用的发生,变质核杂岩的发育与微弱的钙碱性岩浆活动是其最直接的表现。区域古地磁资料分析表明,印度-欧亚板块之间的板块相互作用、区域板块与地块的旋转以及由此所致的不同构造环境制约着各种地质事件的发生与发展。北向运动的印度板块的旋转致使三江地块在新生代演化中发生了两次规模与特点不一的地块旋转过程,即早期的大角度快速旋转和晚期的小角度慢速旋转事件。它们分别对应于早期的递进收缩变形、走滑事件和具有碰撞弧属性的碱性岩浆活动与中期的区域伸展、变质核杂岩的发育与微弱的钙碱性岩浆活动性,以及后期的递进伸展作用和晚期陆内碱性岩浆活动性。

东天山康古尔塔格金矿带构造与成矿规律

康古尔塔格金矿带是近几年新疆东天山境内发现的重要成矿带。以康古尔塔格─黄山断裂为一级板块边界，其南发育晚古生代岛弧系和巨型韧性剪切带，后者东西延伸数百km，强弱应变相间，分四期变形，第二、三期变形与金矿关系最为密切。晚古生代碰撞构造及其演化与金成矿亦具有重要的时空控制关系。碰撞花岗岩系列特征与成矿对应关系明显。成矿构造演化分三个阶段，提出了六条该区构造演化与成矿规律方面的认识，表明该带构造控矿和动力（变质）热液成矿均较明显。

大陆造山运动:从大洋俯冲到大陆俯冲、碰撞、折返的时限--以北祁连山、柴北缘为例

北祁连山和柴北缘是典型的早古生代大陆造山带,分别发育有北祁连山大洋型俯冲缝合带和柴北缘大陆型俯冲碰撞带。作为早古生代大洋冷俯冲的典型代表,北祁连山经历了从新元古代-寒武纪大洋扩张、奥陶纪俯冲和闭合及早泥盆世隆升造山的过程。高压变质岩变质年龄为490～440Ma,证明古祁连洋经历了至少50m.y.的俯冲过程。柴北缘超高压变质带是大陆深俯冲的结果,岩石学、地球化学和同位素年代学表明,柴北缘超高压变质带中榴辉岩的原岩分别来自洋壳和陆壳两种环境。高压/超高压变质的蛇绿岩原岩的年龄为517±11Ma,与祁连山蛇绿岩年龄一致。榴辉岩早期的变质年龄为443～473Ma,与祁连山高压变质年龄一致,代表大洋地壳俯冲的时代,而柯石英片麻岩和石榴橄榄岩所限定的超高压变质时代为420～426Ma,代表大陆俯冲的年龄。从大洋俯冲结束到大陆俯冲最大深度的转换时间最少需要20m.y.。自420Ma起,俯冲的大洋岩石圈与跟随俯冲的大陆岩石圈断离,大陆地壳开始折返,发生隆升和造山。北祁连山和柴北缘两个不同类型的高压-超高压变质带反映了早古生代从大洋俯冲到大陆俯冲、隆升折返的造山过程。