中国大陆科学钻探主孔0～4500米变质岩石锆石中保存的超高压矿物包体   总被引：14，自引：9，他引：14  

刘福来许志琴  薛怀民孟繁聪 《岩石学报》2005,21(2):277-292

中国大陆科学钻探主孔0-4500米的岩心主要由榴辉岩、斜长角闪岩、副片麻岩、正片麻岩以及少量的超基性岩所组成。岩相学研究结果表明,榴辉岩的围岩普遍经历了强烈角闪岩相退变质作用的改造,峰期超高压变质的矿物组合已完全被后期退变质过程中角闪岩相矿物组合所替代。采用激光拉曼技术,配备电子探针和阴极发光测试,发现主孔224件岩心中有121件(包括榴辉岩、斜长角闪岩、副片麻岩和正片麻岩)样品的锆石中普遍隐藏以柯石英为代表的超高压矿物包体,且不同岩石类型锆石中所保存的超高压矿物包体组合存在明显差异。(含多硅白云母)金红石石英榴辉岩锆石中保存的典型超高压包体矿物组合为柯石英 石榴石、柯石英 石榴石 绿辉石 金红石和柯石英 多硅白云母 磷灰石。黑云绿帘斜长角闪岩锆石中保存的超高压矿物组合为柯石英 石榴石 绿辉石、柯石英 石榴石 多硅白云母和柯石英 绿辉石 金红石,与榴辉岩所保存的超高压矿物组合十分相似,表明该类斜长角闪岩是由超高压榴辉岩在构造折返过程中退变质而成。在副片麻岩类岩石,如石榴绿帘黑云二长片麻岩锆石中,代表性的超高压包体矿物组合为柯石英 多硅白云母和柯石英 石榴石等;而在石榴黑云角闪钠长片麻岩锆石中,则保存柯石英 硬玉 石榴石 磷灰石、柯石英 硬玉 多硅白云母 磷灰石和柯石英 石榴石 磷灰石等超高压矿物包体。在正片麻岩锆石中,标志性的超高压矿物包体为柯石英、柯石英 多硅白云母、柯石英 蓝晶石 磷灰石和柯石英 蓝晶石 榍石等。此外,在南苏鲁东海至临沭一带的地表露头以及一系列卫星孔岩心的锆石中,也普遍发现以柯石英为代表的标志性超高压矿物包体,表明在南苏鲁地区由榴辉岩及其围岩的原岩所组成的巨量陆壳物质(方圆>5000km2,厚度超过4.5km)曾整体发生深俯冲,并经历了超高压变质作用。该项研究对于重塑苏鲁-大别超高压变质带俯冲-折返的动力学模式有着重要的科学意义。  相似文献   

与理想同行 纪念《干旱区地理》创刊三十周年     

《干旱区地理》编辑部 《干旱区地理》2008,31(4)

2008年,我国在改革开放的大道上已经走过了三十年.三十年前的1978年中国正是处在文革浩劫之后百业凋敝、百废待举的时期.<干旱区地理>就在这个时期创刊的,她的创刊,是我国干旱区地学学术刊物发展的一个重要标志.三十年来编辑部全体成员在研究所领导的支持、关心和历届编委以及科技人员的指导、鼓励、帮助下,发扬艰苦奋斗,开拓创新精神,一步一个脚印地走到了今天,忆往昔感慨万千,三十年的辛勤耕耘,三十年的春花秋实,<干旱区地理>构建了能为广大科技工作者在干旱区地理领域展示科学研究,成果交流与信息共享平台.  相似文献   

Determining the motion of the Solar system relative to the cosmic microwave background using Type Ia supernovae     

Christopher Gordon  Kate Land  An&#;e Slosar 《Monthly notices of the Royal Astronomical Society》2008,387(1):371-376

We estimate the Solar system motion relative to the cosmic microwave background using Type Ia supernovae (SNe) measurements. We take into account the correlations in the error bars of the SNe measurements arising from correlated peculiar velocities. Without accounting for correlations in the peculiar velocities, the SNe data we use appear to detect the peculiar velocity of the Solar system at about the 3.5σ level. However, when the correlations are correctly accounted for, the SNe data only detect the Solar system peculiar velocity at about the 2.5σ level. We forecast that the Solar system peculiar velocity will be detected at the 9σ level by GAIA and the 11σ level by the Large Synoptic Survey Telescope. For these surveys, we find the correlations are much less important as most of the signal comes from higher redshifts where the number density of SNe is insufficient for the correlations to be important.  相似文献   

Architecture and Kinematics of the Dabie Orogen,Central Eastern China   总被引：3，自引：0，他引：3  

XU Shutong  LIU Yican  CHEN Guanbao  WU Weiping Anhui Institute of Geology  Hefei  Anhui  Laboratory of Continental Dynamics of the Ministry of Land  Resources  Beijing 《《地质学报》英文版》2005,79(3):356-371

The geometry of the Dabie Mountains is manifested in terms of the distribution of petro-tectonic units in three dimensions. It is identified into three segments from east to west, four horizons in vertical profiles and eight petrotectonic units from north to south. Three segments are the east, middle and west segments. Four horizons, from top to bottom, are two different meta-tectonic melange in the uppermost part, underthrust basement and cover below them, and mantle at the bottom of the profiles. Eight petro-tectonic units from north to south are: (1) the hinterland basin, (2) the meta-flysch, (3) the ultramafic rock belt (UM) Sujiahe eclogite belt (SH), (4) eclogite belt 2 (Ec2) with most eclogites of continental affinity, (5) eclogite belt 1 (Ecl1) with some eclogite of oceanic affinity, (6) the Dabie complex or underthrust basement of the Yangtze continent, (7) the Susong and Zhangbaling Groups or underthrust cover of the Yangtze continent and (8) the foreland belt. The (3), (4) and (5) units belong to meta-tectonic melange. Some ultrahigh pressure metamorphic minerals such as coesite and micro-diamonds have been found in (3) and (4) units; a possible ultrahigh pressure mineral,clinozoisite aggregate pseudomorph after lawsonite, was found in unit (5). The three tectonic units are speculated to be coherent initially; the UM and SH units are suggested to be the root belt in the east, middle and west segments respectively.The kinematics of the Dabie orogen is divided into three stages: top-to-south thrusting during the eclogite-granulite facies metamorphism, top-to-north extension during the amphibolite metamorphic stage, and faults or shear bands of brittle deformation and greenschist facies metamorphism were formed in the post-orogenic stage since the Late Jurassic and the movement pictures of these faults is different from each other.  相似文献   

扬子地块泥盆纪—石炭纪古地磁新结果及其古地地理意义   总被引：15，自引：1，他引：15  

张世红  朱鸿等 《地质学报》2001,75(3):303-313

本文通过对扬子地块西南缘贵州独山－平塘地区泥盆－石炭纪316块定向岩心样品的系统退磁处理，揭示出晚侏罗世、新生代两期重磁化成.73个岩心样品，分布在早一中泥盆世（17个）、晚泥盆世（25个）、早石炭世（24个）和中－晚石炭世（7个）4个统计单元，得到了最可能的原生剩磁。结合已有的古地磁数据，修订了扬子地块极移曲,纯利 移曲线拟合的结果表明，扬子地块在早古生代是冈瓦那大陆的组成部分，与印度－喜马拉雅－澳大利亚地区临近。晚泥盆世、冈瓦那大陆发生大规模顺时针旋转，扬子地块开始与之分离。  相似文献   

东天山红柳河地区海西期花岗岩的岩石学、地球化学及其构造环境   总被引：10，自引：1，他引：10       下载免费PDF全文

李伍平  王涛等 《地质论评》2001,47(4):368-376

东天山红柳河地区分布着大量的海西期花岗岩体，从早到晚，依次为河西站岩体、红柳河岩体、河西岩体和天湖岩体，主要岩石类型为花岗闪长岩、二长花岗岩和斜长花岗岩，河西站和红柳河花岗岩的岩相学和地球化学具有S型花岗岩的特征，而河西岩体和天湖岩体显示出I型花岗岩特征，河西花岗岩微量元素含量最低，具Eu弱正异常，类似于adakite岩地球化学特点；其他花岗岩微量元素含量高，具Eu负异常，与洋脊花岗岩相比，该区花岗岩不同程度地富集K2O、Rb、Ba、Th和Ce，亏损Ta、Nb、Zr、Hf、Y、Yb等，河西花岗岩、河西站和红柳河花岗岩、天湖花岗岩分别具有火山弧、同碰撞才碰撞后花岗岩特点，河西花岗岩和其他花岗岩分别起源于先前存在的大洋拉斑玄武岩残片和古老地壳岩石的部分熔融，这些花岗岩均形成于陆内造山环境，与东天山海西晚期地壳-岩石圈的挤压和伸展作用有关。  相似文献   

Utilizing a Digital Model to Determine the Hydraulic Properties of a Layered Aquifer     

Larry F. Land 《Ground water》1977,15(2):153-159

  相似文献   

Primordial refractory metal particles in the Allende meteorite     

M. Blander  L.H. Fuchs  C. Horowitz  R. Land 《Geochimica et cosmochimica acta》1980,44(2):217-223

Refractory metal particles containing Os, Re, W, Mo, Ir, and Ru were observed in a Ca-Al-rich inclusion in the Allende meteorite. These particles are the closest to unaltered primordial metal condensates from a nebula yet reported, and appear to have been isolated from the nebula before the condensation of refractories was complete. Computer calculations of condensation indicate that the temperature of isolation appears to be close to the calculated temperature of first formation of oxides (~ 1620 K at 10^?4 atm) indicating that isolation may have been effected by coating of the particles by oxides.  相似文献   

辽东古元古代富镁质碳酸盐岩建造菱镁矿滑石矿床成矿流体研究   总被引：4，自引：0，他引：4  

陈从喜 倪培蔡克勤  翟裕生邓军 《地质论评》2003,49(6):646-651

辽东地区古元古代大石桥组中分布有富镁质碳酸盐岩建造，并产有大型或超大型菱镁矿、滑石矿床。笔者等近期在该地区野外工作中发现了沉积型石膏岩，并对其和菱镁矿滑石围岩进行了相应的稳定同位素和流体包裹体研究。稳定同位素分析结果为δ^13C一般-1．8‰～ 1．2‰、δ^18Ol0‰～20‰，δ^14SVCDT23．9‰～26．5‰；结合菱镁矿和白云岩流体包裹体形态和成分特征，笔者等认为早期镁质非金属矿床的形成与古元古代的海相蒸发岩系有关，古海水演化而来的变质成矿流体对后期滑石矿床的形成起着重要的控制作用。  相似文献   

Post-collisional Adakitic Porphyries in Tibet: Geochemical and Sr-Nd-Pb Isotopic Constraints on Partial Melting of Oceanic Lithosphere and Crust-Mantle Interaction   总被引：15，自引：0，他引：15  

GAO Yongfeng  HOU Zengqian  WEI Ruihua  ZHAO RongshengShijiazhuang College of Economy  Huainan Ro  Shijiazhuang  Hebei  E-mail: gao@sina.comInstitute of Mineral Resources  Chinese Academy of Geological Sciences  Beijing Hebei Bureau of Land  Resources  Shijiazhuang  Hebei 《《地质学报》英文版》2003,77(2):194-203

The distribution of Neogene felsic porphyries intruding in earlier granitic batholiths was mainly controlled by north-south-tending rifting zones and normal faults. The main rock types of the felsic porphyries include granodiorite-porphyry, monzonitic granite-porphyry and quartz monzonitic porphyry. The porphyries are characterized by high SiO2 ((?)64.26%) and Al2O3 (>15% at 70% SiO2), low Y and HREE (Yb) contents, strong enrichment of LILE and LERR, especially K and ST. Geochemical features of the porphyries show distinct adakitic magma affinity. Nd, Sr and Pb isotopic compositions of the porphyries form a linear alignment from MORB to EM2, suggesting a mixing of the MORB reservoir with the metasomatized mantle reservoir. Considering also the geochemical characteristics of the porphyries and the sequence of observable structural-thermal-magmatic events at Gangdise, it is thought that the Neogene porphyries were formed by partial melting of dead subducted oceanic crust in a post-collision setting. K-enr  相似文献