额尔齐斯碰撞带东段结构与形成时代   总被引：2，自引：1，他引：1  

洪涛  相鹏  游军  张连昌  吴楚  吴琪  徐兴旺 《岩石学报》2015,31(2):571-593

阿尔泰地体与萨吾尔岛弧之间的额尔齐斯碰撞带其结构与形成时代是中亚造山带构造演化研究的热点问题之一。本文报道了额尔齐斯碰撞带东段结构与形成时代的研究结果。新的结果显示:额尔齐斯碰撞带东段由4个走向NWNNW陡立的韧性变形带组成,剖面上呈扇状挤压变形的结构;这4个韧性变形带的应变类型为收缩应变与平面应变;片理带的变形从宏观到微观都表现出对称的结构,不同变形带不同地段可具变化的流动方向而表现出"奶油饼结构",其可能整体形成于共轴挤压机制;玉勒肯与老山口韧性变形带花岗闪长质糜棱岩、花岗闪长质超糜棱岩中变质重结晶锆石U-Pb定年结果显示韧性变形时间约为360Ma。这可能意味着早石炭世时卡拉先格尔地区已进入碰撞阶段,即萨吾尔岛弧与阿尔泰地体间在360Ma时已发生碰撞。  相似文献   

天山—阿尔泰地区古生代构造成矿作用   总被引：1，自引：1，他引：0       下载免费PDF全文

万天丰  赵庆乐 《中国地质》2015,(2):365-378

天山—阿尔泰地区古生代大地构造及其相关的内生金属成矿作用是一个重要而又有趣的研究课题。阿尔泰地区属于早古生代碰撞带,天山地区属于晚古生代早期(晚泥盆世—早石炭世,385~323 Ma)碰撞带,均为区域性近南北向(按现代磁方位)缩短-碰撞作用的结果。在晚泥盆世—早石炭世碰撞作用下,阿尔泰地区近NW向区域性断层呈现为右行走滑的特征,天山地区近东西向的区域性断层表现为逆断层的活动。然而,在晚石炭世—二叠纪(323~260 Ma)受乌拉尔碰撞带向东挤压作用的远程效应影响,该地区受到较弱的向东挤压作用,阿尔泰地区NW向断层转变成左行走滑断层,天山地区近东西向的断层则转为右行走滑断层,使该区岩石发生适度的破碎,以致在天山—阿尔泰地区形成大量世界著名的大型内生金属矿床。对于亚洲大陆来说,碰撞作用最强烈的时期并不一定是内生金属成矿作用最有利的阶段。应该审慎地对待"造山带成矿"假说。  相似文献   

蓝离散星研究现状(Ⅰ):形成机制     

新宇  邓李才  梁艳春 《天文学进展》2006,24(2):129-141

大量研究表明,蓝离散星的形成可能有多种机制,目前比较流行的形成机制可以概括为以下几类:密近双星系统的质量传输及双星并合、密集星场的恒星碰撞,以及包含双星系统的恒星间 (双星-单星、双星-双星)相互作用导致的恒星并合。与此同时,蓝离散星在各类恒星系统中的普遍存在,也使得研究这类恒星的形成及演化成为追踪恒星系统动力学演化、化学演化及积分光谱性质变化的有效指针。  相似文献   

Palaeomagnetic study of eastern Tibet—deformation of the Three Rivers region     

Y. Otofuji  Y. Inoue  S. Funahara  F. Murata  X. Zheng 《Geophysical Journal International》1990,103(1):85-94

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A compact model for the planar rhomboidal 4-body problem     

Ernesto A. Lacomba  Ernesto Pérez-Chavela 《Celestial Mechanics and Dynamical Astronomy》1992,54(4):343-355

We obtain a compact model for the global study of the planar rhomboidal 4-body problem in a level of constant negative energy. This model is a variation of the non compact model obtained through a McGehee blow up transformation. but compactness permits to obtain results which are not clear in the other case.  相似文献   

Controls on P–T–t deformation path from amphibole zonation during progressive metamorphism of basic rocks (estuary of the River Vilaine, South Brittany, France)     

Cl. TRIBOULET  Cl. AUDREN 《Journal of Metamorphic Geology》1988,6(2):117-133

Abstract Edenite/tremolite and edenite/magnesio-hornblende in equilibrium with plagioclase, chlorite, epidote, quartz and vapour involve several types of reactions for which K _D can be related to T and P. Thermodynamic calculation of these equilibria leads to isopleth systems. Given knowledge of the progressive changes of end-member activities in zoned Ca–Mg amphiboles (based on microprobe analyses), it is possible to construct precise pressure–temperature–time paths ( P–T–t paths) which have been followed by metabasites during polyphase metamorphism. When applied to basic rocks from the River Vilaine area, this method allows us to construct a P–T–t path that can be compared directly to the P–T–t path constructed from interbedded acid rocks (aluminous micaschists) in the same structural unit. Through time, both basic and acid rocks underwent the same complex deformation history that can be described conveniently in the L–S fabric system of Flinn. This allows us to construct a P–T–t deformation path for this structural unit.
These paths are interpreted in terms of an under/overthrusting continental collision belt (the Hercynian belt), and represent an illustration of the time delay caused by stacking of more than two crustal units.  相似文献   

Numerical study of continental collision: influence of buoyancy forces and an initial stiff inclusion   总被引：2，自引：0，他引：2  

J. P. Vilotte  R. Madariaga  M. Daignières  O. Zienkiewicz 《Geophysical Journal International》1986,84(2):279-310

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Shock metamorphism on the moon     

Yasunori Miura  Toshio Kato 《Celestial Mechanics and Dynamical Astronomy》1992,54(1-3):245-248

Shock metamorphism of the lunar samples is discussed. All types of lunar glasses formed by various-size collision-type impact are found as impact glass, ropy glass and agglutinates. The agglutinates bonded by crystal and glassy materials contain hydrogen and helium from the solar wind components. Lunar shocked minerals of plagioclase and silica show anomalous compositions and densities. There are typical two formation processes on planetary materials formed by shock events; that is (1) shocked quartz formed by silica-rich target rocks (esp. on evolved planets of the Earth and Mars), and (2) shocked silica with minor Al contents formed from plagioclase-rich primordial crusts of the Moon. The both shocked silica grows to coarse-grain normal crystals after high-temperature metamorphism which cannot distinguish the original main formation event of impact process.  相似文献   

星际分子正—NH3和He的超精细跃迁碰撞截面和速率系数的理论计算     

陈激  张亚辉 《天文学报》1997,38(3):225-230

本文采用Ｒ矩阵传播方法，通过求解ＣＳ近似下的耦合方程，计算了星际分子云条件下正－ＮＨ３分子和Ｈｅ碰撞的超精细跃迁碰撞截面和速率系数，为研究天体的信息提供需用的基础数据。  相似文献   

Deep root of a continent-continent collision belt: Evidence from the Chinese Continental Scientific Drilling (CCSD) deep borehole in the Sulu ultrahigh-pressure (HP-UHP) metamorphic terrane, China   总被引：2，自引：0，他引：2  

Zhiqin Xu  Shaocheng Ji  Zeming Zhang  Qin Wang 《Tectonophysics》2009,475(2):204-219

The Chinese Continental Scientific Drilling (CCSD) deep borehole, which reached a depth of 5158 m in the Sulu ultrahigh-pressure (UHP) metamorphic terrane, provides a new window into the deep root of a continent-continent collision belt, and the tectonic processes by which supracrustal material is recycled into the mantle by subduction and then uplifted to the surface. Major research themes of the CCSD project were to: (1) determine the three-dimensional composition, structure and geophysical character of the deep root of this orogenic belt; (2) investigate the nature and timing of the UHP metamorphism; (3) investigate the processes of crust-mantle interaction involved in the formation and exhumation of the UHP rocks; (4) study the process of fluid circulation and mineralization during subduction and exhumation; (5) study the rheological properties of the various rocks during subduction and exhumation; (6) develop and refine dynamic models for deep subduction and exhumation of crustal rocks, and (7) establish a long-term, natural laboratory for the study of present-day crustal dynamics (e.g., stress, strain, fluid activity). The CCSD has developed precise oriented profiles of the main borehole in terms of lithology, geochemistry, oxygen isotopes, zircon SHRIMP U-Pb ages, ⁴⁰Ar-³⁹Ar ages, deformation, rheology, mineralization, physical properties of the rocks, petrophysical logs, seismic reflections and underground fluids. The present paper summarizes the integrated research results of this project, especially the new findings concerning the deep root of a continent-continent collision.  相似文献