吉黑东部中生代两种机制的碰撞构造

吉林、黑龙江东部地区中生代存在两种机制的碰撞构造，即由南北陆块碰撞（华北古板块与张广才—佳木斯地块）所形成的近东西走向的构造（古洞河—富尔河碰撞带）和东部地体向陆缘增生挤压所产生的南北走向的褶皱—推覆构造。前者由早期构造杂岩带及叠加于其上的印支期韧性剪切带和推覆构造所代表，后者是在印支期的褶皱和糜棱岩化带之上发育的推覆构造。两种碰撞构造的主要发育时期为晚中生代（Ｊ＿３—Ｋ）。     

内蒙古中部早古生代地体的拼合与增置

内蒙古中部布龙山、温都尔庙一带的蛇绿岩套、蓝门石片岩及其南邻的华北地台两者在空间上以川井－布鲁台庙深大断裂带为界，在时间上具有截然不同的地质演化特点。其内部在构造演化史上也不尽相同，可进一步划分为布龙山－哈拉地层地体和白乃庙－温都尔庙混杂地体。这两个曾分离着的地体，经长时期的运移，于晚志留世之前拼合联为一体，构成早古生代联合地体。直到早二叠世才增置于中朝古板块北缘（或华北地台北缘）。     

The Crustal Structure and Assembly of Terranes in the Qaidam-Qilian-Beishan Area, Western China

Through a study of the geotransect from Golmud to Ejin Qi published recently, the tectonics of the crust beneath the area from the northern Qinghai-Tibet plateau (Qaidam and the Qilian Mountains) to the border between China and Mongolia and its structure, composition and tectonic evolution have been revealed, and abundant information about the deep structures has been provided. Based on the research into the geotransect, it is suggested that the crust in this area was formed by the assembly of the terranes in different geological stages. Following the formation of the Palaeo-Asian continent, the north part of the corridor of the transect became a part of the huge unifying continent by the end of the Early Permian. In the Mesozoic and Cenozoic, as a result of the compression mainly by the push of the Qinghai-Tibet plateau on the south, the unique crustal structure and geomorphologic features on the northern Qinghai-Tibet plateau were formed. This geotransect together with the Yadong-Golmud geotransect co     

松潘-甘孜造山带西部碰撞结合带古生代裂解史初探

通过对近年的区域地质调查成果总结,认为松潘-甘孜造山带西部碰撞结合带在古生代经历了三个重要的发展时期:早古生代先后形成金沙江裂陷槽和理塘裂陷槽;晚古生代中晚期形成金沙江洋和理塘裂谷;晚古代生代末期至中三叠世早期,金沙江洋关闭,理塘洋形成,二者是相互关联的。     

Geochronology and geochemistry of early Paleozoic granitic and coeval mafic rocks from the Tannuola terrane (Tuva,Russia): Implications for transition from a subduction to post-collisional setting in the northern part of the Central Asian Orogenic Belt

Early Paleozoic magmatism of the Tannuola terrane located in the northern Central Asian Orogenic Belt is important to understanding the transition from subduction to post-collision settings. In this study, we report in situ zircon U-Pb ages, whole rock geochemistry, and Sr-Nd isotopic data from the mafic and granitic rocks of the eastern Tannuola terrane to better characterize their petrogenesis and to investigate changing of the tectonic setting and geodynamic evolution. Zircon U-Pb ages reveal three magmatic episodes for about 60 Ma from ∼510 to ∼450 Ma, that can be divided into the late Cambrian (∼510–490 Ma), the Early Ordovician (∼480–470 Ma) and the Middle-Late Ordovician (∼460–450 Ma) stages. The late Cambrian episode emplaced the mafic, intermediate and granitic rocks with volcanic arc affinity. The late Cambrian mafic rocks of the Tannuola terrane may originate from melting of mantle source that contain asthenosphere and subarc enriched mantle metasomatized by melts derived from sinking oceanic slab. Geochemical and isotopic compositions indicate the late Cambrian intermediate-granitic rocks are most consistent with an origin from a mixed source including fractionation of mantle-derived magmas and crustal-derived components. The Early Ordovician episode reveal bimodal intrusions containing mafic rocks and adakite-like granitic rocks implying the transition from a thinner to a thicker lower crust. The Early Ordovician mafic rocks are formed as a result of high degree melting of mantle source including dominantly depleted mantle and subordinate mantle metasomatized by fluid components while coeval granitic rocks were derived from partial melting of the high Sr/Y mafic rocks. The latest Middle-Late Ordovician magmatic episode emplaced high-K calc-alkaline ferroan granitic rocks that were formed through the partial melting the juvenile Neoproterozoic sources.These three episodes of magmatism identified in the eastern Tannuola terrane are interpreted as reflecting the transition from subduction to post-collision settings during the early Paleozoic. The emplacement of voluminous magmatic rocks was induced by several stages of asthenospheric upwelling in various geodynamic settings. The late Cambrian episode of magmatism was triggered by the slab break-off while subsequent Early Ordovician episode followed the switch to a collisional setting with thickening of the lower crust and the intrusion of mantle-induced bimodal magmatism. During the post-collisional stage, the large-scale lithospheric delamination provides the magma generation for the Middle-Late Ordovician granitic rocks.     

苏北东海榴辉岩氢氧同位素地球化学研究

研究了苏鲁地体西部东海地区超高压变质榴辉岩的氢氧同位素组成,得到绿辉石和石榴子石的δ＾１８Ｏ值变化较大（为－１０．４‰－＋４．８‰）,多硅白云母的δＤ值变化较小（为－１０４‰－－８３‰）不同矿物对之间达到保存了氧同位素平衡,得到了一致的同位素温度（６５０－７５０℃）,榴辉岩具有低至－１０‰和－１０４‰的异常δ＾１８Ｏ和δＤ值表明,岩石与极贫＾１８Ｏ和Ｄ的大气降水成因流体发生过氢氧同位素交换,同时排     

辽东-吉南地区早元古代变质地体的组成及主要特征

在辽东－吉南地区存在两个性质不同的变质地体：辽北地体和辽南地体,二者之间以断裂带或韧性剪切带相接。辽北地体包括北辽河群和老岭群,辽南地体包括南辽河群和集安群。不同变质地体内的早元古代变质岩系在地层系统及岩石组合、原岩建造及沉积环境、变质作用类型及ｐＴｔ轨迹、区域构造和岩浆活动等方面都存在明显的差别。它们在早元古代时期形成于不同的大陆边缘,具有完全不同的形成条件和演化历史。两个变质地体最晚在早元古代晚期经构造作用拼贴在一起。     

山东半岛的地体构造及金矿成矿的区域地质背景

本文以不整合面的发现及同位素年龄为依据,重新厘定了本区早前寒武纪的地层,从而搞清了本区的大地构造格架,认为它类似于加拿大地盾的“洋葱构造”。本文将山东半岛划分为４个地体：胶北地体,鲁西地体,胶南地体,胶东南－苏东北－黄海地体。认为胶北地体成矿的大地构造背景与南克拉通成矿背景十分相似。胶南地体,黄海地体对胶北地体的俯冲作用为胶北地体提供了成岩成矿物质。根据胶北群和齐山群的地质及及地球化学特征,认为胶     

西藏南羌塘侏罗系色哇组构造变形特征及其构造意义

班公湖—怒江洋的演化一直以来备受关注, 对于其俯冲极性有不同的认识, 前人大多从岩石学、 地球化学等方面的证据去探讨, 而缺乏构造变形的相关研究。本文以构造解析理论为指导, 通过野外大比例尺填图、 构造实测剖面等工作对研究区色哇组的构造样式、 变形期次等进行了研究。综合研究表明, 西藏热那错地区和荣玛地区侏罗系色哇组地层均发育紧闭的三级复式褶皱以及后期叠加的平缓—开阔褶皱。早期褶皱的褶皱轴近东西向展布, 板劈理近东西走向, 是南北向挤压作用的产物。在热那错地区早白垩世美日切错组火山岩角度不整合于已变形的侏罗系色哇组之上, 且色哇组紧闭褶皱的构造样式未在美日切错组火山岩中发育, 推断色哇组紧闭褶皱发生在早白垩世之前。结合研究区大地构造背景, 推断研究区内侏罗系色哇组地层的早期紧闭的三级复式褶皱是班公湖—怒江洋向北俯冲的产物, 而后期叠加的平缓—开阔褶皱可能与羌南地块和拉萨地块的碰撞有关。     

喜马拉雅东构造结——南迦巴瓦构造及组构运动学

喜马拉雅东端-南迦巴瓦构造结的构造格架总体呈现由叠置构造岩片构成的复式背形构造.自NW到SE由比鲁构造岩片、直白构造岩片、南派乡构造岩片和多雄拉变质穹隆组成,它们之间的界限分别是直白-丹娘-南伊沟韧性拆离断裂、直白-丹娘韧性逆冲断裂和多雄拉韧性逆冲断裂.由高压麻粒岩相组成的直白构造岩片被直白-丹娘-南伊沟韧性拆离断裂和直白-丹娘韧性逆冲断裂所夹持,为挤出构造岩片.根据印度斯-雅鲁藏布江大拐弯缝合带西侧和北侧的变形特征及石英组构运动学的EBSD测量结果,表明大拐弯缝合带存在各段的差异,并具有逐渐演化的特征.大拐弯缝合带的北端为拉月-迫隆乡韧性逆冲剪切带;西段为鲁朗-拉月左行走滑剪切带,西南段为嘎马-米林左行伸展转换剪切带,指示南迦巴瓦变质体相对拉萨地体的运动转为水平走滑运动.根据大拐弯缝合带东侧右行走滑和西侧左行走滑特征,推测在印度-亚洲碰撞之后,南迦巴瓦变质体受制于这两条走滑断裂,而相对喜马拉雅地体向北推移,并深深插入拉萨地体之下,形成东构造结.由于南迦巴瓦变质体的强烈上隆,其上部原存的特提斯喜马拉雅的古生代-中生代盖层沉积被俯冲和被剥蚀贻尽.南迦巴瓦变质体中直白组高压麻粒岩相中石榴石辉石岩形成的温压条件(T=800～900℃,P=2.6～2.8GPa)表明,岩石经历了相当于80km～100km深度的峰期榴辉岩变质作用的条件,印度板片深俯冲于拉萨地体之下又折返挤出到由派乡组和多雄拉组角闪岩相(混合岩化)组成的南迦巴瓦变质基底之中.