祁连山新元古代中—晚期至早古生代火山作用与构造演化   总被引：15，自引：3，他引：12       下载免费PDF全文

夏林圻  李向民  余吉远  王国强 《中国地质》2016,(4):1087-1138

祁连山地区的新元古代中—晚期至早古生代火山作用显示系统地时、空变化,其乃是祁连山构造演化的火山响应。随着祁连山构造演化从Rodinia超大陆裂谷化—裂解,经早古生代大洋打开、扩张、洋壳俯冲和弧后伸展,直至洋盆闭合、弧-陆碰撞和陆-陆碰撞,火山作用也逐渐从裂谷和大陆溢流玄武质喷发,经大洋中脊型、岛弧和弧后盆地火山活动,转变为碰撞后裂谷式喷发。850~604 Ma的大陆裂谷和大陆溢流熔岩主要分布于祁连和柴达木陆块。从大约550 Ma至446 Ma,在北祁连和南祁连洋-沟-弧-盆系中广泛发育大洋中脊型、岛弧和弧后盆地型熔岩。与此同时,在祁连陆块中部,发育约522~442 Ma的陆内裂谷火山作用。早古生代洋盆于奥陶纪末(约446 Ma)闭合。随后,从约445 Ma至约428 Ma,于祁连陆块北缘发育碰撞后火山活动。此种时-空变异对形成祁连山的深部地球动力学过程提供了重要约束。该过程包括:(1)地幔柱或超级地幔柱上涌,导致Rodinia超大陆发生裂谷化、裂解、早古生代大洋打开、扩张、俯冲,并伴随岛弧形成;(2)俯冲的大洋板片回转,致使弧后伸展,进而形成弧后盆地;(3)洋盆闭合、板片断离,继而发生软流圈上涌,诱发碰撞后火山活动。晚志留世至早泥盆世(420~400 Ma),先期俯冲的地壳物质折返,发生强烈的造山活动。400 Ma后,山体垮塌、岩石圈伸展,相应发生碰撞后花岗质侵入活动。  相似文献   

青藏高原大陆动力学研究若干进展   总被引：15，自引：4，他引：11       下载免费PDF全文

许志琴  杨经绥  侯增谦  张泽明  曾令森  李海兵  张建新  李忠海  马绪宣 《中国地质》2016,(1):1-42

近10年来,"大陆构造与动力学实验室"在青藏高原大陆动力学研究,尤其在特提斯演化和青藏高原生长方面取得若干进展,包括(1)"青藏高原——造山的高原"理念的提出;(2)青藏高原特提斯体制和构造格架的再造;(3)新特提斯蛇绿岩中原位金刚石和深地幔矿物群的重大发现;(4)新特提斯洋盆俯冲新机制的揭示;(5)印度/亚洲碰撞的早期岩浆和喜马拉雅折返中的作用;(6)喜马拉雅三维碰撞造山机制和折返全过程的初步建立;(7)青藏高原东南缘物质逃逸的新机制——"弯曲与地壳解耦"的提出;(8)青藏高原俯冲型、碰撞型及陆内型片麻岩穹窿;(9)青藏高原东缘汶川强震的构造背景和强震机制;(10)青藏高原碰撞造山成矿模式;(11)印度/亚洲碰撞过程的数值模拟。综述和集成上述成果是为了与同行们交流磋商,进一步共同发展青藏高原大陆动力学理论,向国际地学前沿的冲刺。  相似文献   

Geological evolution and hydrocarbon potential of the salt-cored Hoodoo Dome,Sverdrup Basin,Arctic Canada     

《Marine and Petroleum Geology》2016

The evaporite-cored Hoodoo Dome on southern Ellef Ringnes Island, Sverdrup Basin, was examined to improve the understanding of its structural geological history in relation to hydrocarbon migration. Data from geological mapping, reflection seismic, thermal maturity and detrital apatite (U–Th)/He cooling ages are presented. Five stages of diapirism are interpreted from Jurassic to Recent times:1. 180 to 163 Ma (pre-Deer Bay Formation; development of a diapir with a circular map pattern).2. 163 to 133 Ma (Deer Bay to lower Isachsen formations; development of salt wings).3. 115 to 94 Ma (Christopher and Hassel formations; ongoing diapirism and development of an oval map pattern)4. 79 Ma (Kanguk Formation; reactivation of the central diapir).5. 42 Ma to 65 Ma (Eurekan Orogeny; tightening of the anticline).During phase1, the Hoodoo diapir was circular. During phase 2, salt wings formed along its margin. During phase 3, the Hoodoo Dome geometry evolved into a much larger, elongate, doubly plunging anticline. Phase 4 is inferred from thermochronology data as indicated by a cluster of cooling ages, but the extent of motion during that time is unknown. During Phase 5 the dome was tightened creating approximately 700 m of structural relief. Denudation since the end of the Eurekan Orogeny is estimated to be about 600 m.A one dimensional burial history model predicts hydrocarbon generation from Middle and Late Triassic source rocks between 140 and 66 Ma, with majority of hydrocarbon expulsion between 117 and 79 Ma. Hydrocarbon generation post-dates salt wing formation, so that this trap could host natural gas expelled from Triassic source rocks.  相似文献   

浮托安装进船过程中护舷碰撞力实测研究   总被引：2，自引：1，他引：1  

葛洪亮  李欣  杨建民  田新亮 《海洋工程》2016,34(3):19-27

浮托安装法广泛应用于大型组块海上安装。导管架平台上部组块浮托安装进船过程中,风、浪、流引起的浮托驳船横向运动造成浮托驳船与导管架桩腿的碰撞,碰撞力可能会对导管架结构造成损伤。陆丰7-2上部组块浮托安装中,为了监测碰撞力大小,设计了碰撞力海上监测系统。通过在导管架外侧四个桩腿上安装光纤光栅应变传感器对碰撞过程中导管架桩腿进行应力监测,进而计算碰撞力。对碰撞过程,载荷作用位置、方向进行简化,并对载荷大小及垂向作用位置对计算的影响进行了研究。结构分析模型简化后,测点von-Mises应力与碰撞力大小成正比,对导管架整体结构建模计算并取局部结构计算比例系数,结合应力实测数据计算出进船过程中驳船对导管架桩腿碰撞力。  相似文献   

Isotope Geochronologic and Geochemical Constraints on the Magmatic Associations of the Collisional Orogenic Zone in the West Kunlun Orogen,China     

WANG Chan  LIU Hao  DENG Jianghong  LIU Xianfan  ZHAO Fufeng  WANG Chun  TIAN Xin 《《地质学报》英文版》2018,92(2):482-498

The Jiajiwaxi pluton in the southern portion of the West Kunlun Range can be divided into two collision–related intrusive rock series, i.e., a gabbro–quartz diorite–granodiorite series that formed at 224±2.0 Ma and a monzonitic granite–syenogranite series that formed at 222±2.0 Ma. The systematic analysis of zircon U-Pb geochronology and bulk geochemistry is used to discuss the magmatic origin(material source and thermal source), tectonic setting, genesis and geotectonic implications of these rocks. The results of this analysis indicate that the parent magma of the first series, representing a transition from I-type to S-type granites, formed from thermally triggered partial melting of deep crustal components in an early island–arc–type igneous complex, similar to an I-type granite, during the continental collision orogenic stage. The parent magma of the second series, corresponding to an S-type granite, formed from the partial melting of forearc accretionary wedge sediments in a subduction zone in the late Palaeozoic–Triassic. During continued collision, the second series magma was emplaced into the first series pluton along a central fault zone in the original island arc region, forming an immiscible puncture-type complex. The deep tectonothermal events associated with the continent–continent collision during the orogenic cycle are constrained by the compositions and origins of the two series. The new information provided by this paper will aid in future research into the dynamic mechanisms affecting magmatic evolution in the West Kunlun orogenic belt.  相似文献   

Petrogenesis of the Late Cenozoic collision volcanism in the central part of the Lesser Caucasus (Azerbaijan)     

N.A. Imamverdiyev  M.Ya. Gasangulieva  G.J. Babaeva  Sh.F. Abdullaeva  A.A. Veliev 《Russian Geology and Geophysics》2018,59(1):41-54

The Late Cenozoic volcanics of the Lesser Caucasus have similar trace-element and REE patterns with negative anomalies of Nb, Ta, Hf, and Zr. They are highly enriched in Rb, Ba, Th, and La and depleted in Ti, Yb, and Y with respect to N-MORB, which indicates their formation from the subduction-metasomatized lithospheric mantle. Partial melting of the subcontinental mantle lithosphere and crustal assimilation and fractional crystallization controlled the magma evolution in the collisional magmatic belts.  相似文献   

滇西芦子园远程矽卡岩Pb-Zn-Fe(Cu)多金属矿床流体包裹体初探及矿床成因探讨   总被引：4，自引：4，他引：0  

邓明国  陈伟  王学武  刘凤祥  管申进  卢映祥  余海军  赵发 《岩石学报》2018,34(5):1239-1257

滇西镇康芦子园是"三江"成矿带保山地块内迄今发现的唯一超大型Pb-Zn-Fe(Cu)多金属矿床,是区内系列同类层控热液铅锌矿床的典型代表。矿体呈似层状、脉状及透镜状产于寒武系碳酸盐岩建造的矽卡岩和大理岩层间破碎带,矿石构造以条带状、浸染状和脉状-网脉状为主要特征;围岩蚀变复杂、分带明显,由下至上依次为石榴子石-透辉石-透闪石-阳起石化带→绿泥石-绿帘石-阳起石-蔷薇辉石化带→碳酸盐-大理岩化带。矿床成矿流体从早期到晚期经历了多个矿化阶段。本文选取了该矿床早矽卡岩阶段、晚矽卡岩阶段、石英硫化物阶段和石英碳酸盐阶段的多种脉石矿物及闪锌矿进行了系统的流体包裹体研究。结果显示,早矽卡岩阶段发育微溶CO_2富液相和纯液相水溶液包裹体,并含大量K~+、Na~+、Ca~(2+)、F~-和Cl~-和少量SO_4~(2-),气相成分主要为H_2O、CO_2及少量CH_4和N_2,包裹体均一温度为233.6~315.6℃,盐度为10.6%~17.6%NaCleqv;晚矽卡岩阶段发育含CO_2和子矿物三相包裹体,均一温度214.9~388.0℃,盐度5.9%~16.4%NaCleqv;石英硫化物阶段发育含CO_2的水溶液包裹体,气相成分为CH_4、H_2O和少量CO_2,均一温度150.0~285.0℃,盐度为2.5%~13.8%NaCleqv;石英碳酸盐阶段为单一成分的水溶液包裹体,均一温度为105.0~187.5℃,盐度为0.5%~12.3%NaCleqv。结合H-O同位素研究表明,成矿流体最初来源于具中高温、中高盐度、高K、Na,富CO_2、Cl、F等特征的深部岩浆热液,在石英硫化物阶段开始有大气降水混入,演化为中阶段中低温、低盐度、贫CO_2的热液流体,至成矿晚阶段转化为以大气降水占主导。该矿床成矿环境的改变、流体混合以及流体的沸腾作用可能是导致成矿物质富集沉淀的重要机制。综合矿床地质特征、成矿流体包裹体和HO同位素研究认为,该矿床为与陆陆碰撞造山和深部隐伏岩体有关的远程矽卡岩成矿系统。  相似文献   

湖南及邻区志留纪兰多弗里世鲁丹期至埃隆期岩相古地理及加里东期板块构造演化     

王根贤  陈必河  郑正福  周超 《地质论评》2021,67(6):1557-1585

湖南兰多弗里世鲁丹期岩相古地理格局以桃江—白马山—苗儿山一线为界,其南东为华夏洋壳板块兰多弗里统鲁丹阶周家溪组陆屑浊积深水盆地相,陆屑来自更南东的湘中南褶皱山地;其北西为扬子陆壳板块兰多弗里统鲁丹阶龙马溪组沉积洋盆,南东后缘是上陆棚相,北西前缘是下陆棚相,陆屑都由南东湘中南褶皱山地提供。至兰多弗里世埃隆期岩相古地理发生巨变：龙马溪组顶部Coronograptus cyphus笔石带末即大约440.8±1.2 Ma时,发生华夏洋壳板块向扬子陆壳板块俯冲碰撞事件,华夏洋壳板块周家溪组本身褶皱造山为华夏褶皱山地,华夏洋壳板块洋盆关闭。同时华夏洋壳板块以A型俯冲形式下插到扬子陆壳板块之下,并使扬子陆壳板块南东前缘崛起形成加里东期雪峰造山带。后者将扬子陆壳板块南东前缘牵引、挠曲和凹陷成华夏洋壳板块弧后前陆盆地,小河坝组是该弧后前陆盆地的沉积盖层,陆屑都由南东的雪峰造山带提供。该弧后前陆盆地沉积了三角洲相—滨海相的小河坝组,向北东、北西和南西方向相变为台地相石牛栏组,再向北西陕南紫阳相变为盆地相斑鸠关组。小河坝组两次采集的重砂样均出现蓝闪石,它是蓝闪石片岩标志矿物,蓝闪石片岩是确认加里东期华夏洋壳板块与扬子陆壳板块俯冲碰撞及形成雪峰造山带的判别标志。  相似文献   

U-Pb Zircon and Re-Os Molybdenite Geochronology of theW-Mo Mineralized Region of South Qinling,China, andtheir Tectonic Implications     

HAN Ke  YANG Xingke  CHAO Huixi  HE Hujun  RUAN Shiqi  GAO Yunfeng  ZHANG Weisheng  ZHU Wei  JIN Gang 《《地质学报》英文版》2021,95(2):500-516

A W-Mo mineralized region is located along the northern margin of the South Qinling tectonic belt of China. WMo mineralization occurs mainly in Cambrian–Ordovician clastic and carbonate rocks, and the ore bodies are structurally controlled by NW–SE-and NNE–SSW-striking faults. Evidence for magmatism in the area is widespread and is dominated by intermediate–felsic intrusives or apophyses, such as the Dongjiangkou, Yanzhiba, Lanbandeng, and Sihaiping granitic bodies. Quartz-vein-type mineralization and fault-controlled skarn-type mineralization dominate the ore systems, with additional enrichment in residual deposits. At present, there are few or insufficient studies on(1) the age of mineralization,(2) the relationship between intermediate–felsic granite and W-Mo mineralization,(3) the source of ore-forming materials,and(4) the metallogenic and tectonic setting of the mineralized area. In this paper, we present geochronology results for numerous intrusive granitic bodies in the South Qinling tectonic belt. U-Pb zircon geochronology of the Lanbandeng monzogranite and Wangjiaping biotite monzogranite yields ages of 222.7 ± 2.3 and 201.9 ± 1.8 Ma, respectively. In contrast to the Late Triassic age of the Lanbandeng monzogranite, the age of the newly discovered Wangjiaping biotite monzogranite places it at the Triassic–Jurassic boundary. Re-Os molybdenite geochronology on the Qipangou W-Mo deposit yielded a model age of 199.7 ± 3.9 Ma, indicating the deposit formed in the early Yanshanian period of the Early Jurassic. Granitoid intrusions in the mineralized area are characterized by composite granite bodies that crystallized at ca.240–190 Ma. While there were multiple stages of intrusion, most occurred at 210–220 Ma, with waning magmatic activity at 200–190 Ma. The Re-Os age of molybdenite in the region is ca. 200–190 Ma, which may represent a newly discovered period of W-Mo metallogenesis that occurred during the final stages of magmatism. The heat associated with this magmatism drove ore formation and might have provided additional ore-forming components for metallogenesis(represented by the Wangjiaping biotite monzogranite). Ore materials in the mineralized area were derived from mixed crustal and mantle sources. Enrichment of the region occurred during intracontinental orogenesis in the late Indosinian–Yanshanian, subsequent to the main Indosinian collision. At this time, the tectonic environment was dominated by extension and strike-slip motion.  相似文献   

燕辽东段侏罗、白垩纪构造转变期古地理和古环境的初步分析     

李晓波  张艳  仝亚博 《地学前缘》2021,28(2):391-411

自中、晚侏罗世之交至早白垩世早期,中国东部发生了构造格局和古地理环境的巨大转变。对这一时期燕辽东段古地理和古环境的部分问题进行了多学科整合分析,初步认识如下:中侏罗世开始增强的板块汇聚造成中、晚侏罗世亚洲东部地壳增厚和地势升高,古太平洋伊泽纳崎板块持续俯冲引起深部岩浆上涌、地壳减薄和多期伸展裂陷,同时东亚洋陆过渡带形成一系列逃逸构造,上述构造演化导致燕辽地区在晚侏罗世至早白垩世中期形成高山和盆岭地貌。早白垩世137~131 Ma,嫩江—八里罕断裂至喀喇沁变质核杂岩延伸线两侧出现东高西低的地貌差异,相对下降的冀北—大兴安岭火山-地堑带地层中赋存热河生物群早期化石组合,而辽西—松辽地区为相对隆升的构造高地。130~110 Ma时期裂陷作用扩展,热河生物群中、晚期组合向周围扩散。热河生物群生存时期总体为以干冷为主的温带大陆性气候,这与中生代中国东部高原的潜在环境效应并不矛盾。全球气候演化和区域构造古地理条件共同导致燕辽地区自晚侏罗世至早白垩世的干旱化和寒冷化,并影响到中、晚侏罗世燕辽生物群和早白垩世热河生物群之间的生态群进化演替。  相似文献