东秦岭造山带花岗岩类长石铅同位素组成及其构造学意义

本文对东秦岭造山带内２７个花岗岩类央体４８件长石样品进行了铅同位素成分的测定，结果表明，本区的南秦岭不同时代花岗岩类以贫铀铅和钍铅为特征，具有明显的铅同位素块体效应，反映它们属地同一个铅同位素构造－地球化学省；而本区的北秦岭区岗岩类从晚元古代到早古生长，长石铅同位素组成以富铀铅和钍铅的为特征，但从晚古生长开始，花岗岩类长石铅同位素组成明显发生变化，以贫铀铅和钍铅为特征，反映晚古生长及其后形成花岗质     

矿产开发与环境保护

通过国内多个矿区实例，较系统地叙述了矿产资源开发导致的生态环境破坏和污染状况。表明矿产开发中对环境污染的途径包括河流、土壤、等。最后简要介绍了国内、国外几种对采矿污染比较有效的防治措施。     

中国中央造山带内两个超高压变质带关系

中国中央造山带内至少发育两个超高压变质带,一个是南阿尔金-柴北缘-北秦岭超高压变质带,超高压峰期变质年龄为早古生代(500～400 Ma),代表扬子与中朝克拉通间的深俯冲和碰撞带;另一个是研究程度较高的大别-苏鲁超高压和高压变质带,峰期变质年龄主体是三叠纪(250～220 Ma),代表扬子克拉通内部的陆内大陆深俯冲和碰撞带。对东秦岭看丰沟及香坊沟的变质岩片详细岩石学和构造学研究以及先期造山带尺度的构造、岩石和年代学研究资料分析证明,南阿尔金-柴北缘-北秦岭超高压变质带,向东不能与大别-苏鲁超高压和高压变质带的任一部分相连,包括南大别和西北大别超高压及高压变质岩石。相反,大别-苏鲁超高压及高压变质带,向西经桐柏山,横过南襄盆地延伸到南秦岭的西峡及商南一带。仅在东秦岭-大别山范围内,两个超高压变质带分别位于南丹断裂系南北两侧,沿造山带近平行延展,之间被一系列以断裂或剪切带为边界的岩石构造岩片相隔,不能构成横贯中国中部统一的巨型超高压变质带。任何有关中国中央造山带构造格架及构造演化模型的建立,均应考虑其内部发育两个时代和功能不同的超高压变质带。     

Geochemistry of ophiolite cherts from the Qinling orogenic belt and implications for their tectonic settings

Since the 1980s, one of the important progresses in the study of the Qinling orogenic belt is marked by findings of numerous ophiolite zones[1—4]. On the basis of the former orogenic models of the Paleozoic colli-sional orogeny[1,5,6] and the Mesozoic collision[7—9], another orogenic evolution model from the Paleozoic subduction-collision along the Shangdan suture to the Mesozoic final collision orogeny along the Mianle suture[3,10], including the relicts of the Jining orogeny, has been pr…     

Age of Yingfeng rapakivi granite pluton on the north flank of Qaidam and its geological significance

Rapakivi granite is a very rare and special type of rocks in the crust. Nearly all the typical Proterozoic rapakivi occurred in stable craton, and was regarded as representing special anorogenic settings and rifting events of the supercontinents. Therefore, rapakivi has constantly been attracting the attention of researchers from various countries[15]. For example, the Protero- zoic rapakivi granites occurring in Miyun, Beijing, has been studied in detail by the researchers both at home and …     

新疆博格达山分段及深浅构造转换关系

研究表明 ,天山及邻区自中生代以来一直处于热衰减状态 ,博格达山新生代再造山具有“冷隆升”性 ,盆山边界断裂多限于上地壳内 ,而非直通中地壳低速体甚至上地幔的“深大断裂”。造山带内的韧性剪切带是在古生代形成的 ,而不是再造山期的断裂 ,它对造山带隆升及盆山耦合无贡献 ,博格达山的隆升为复式背斜构造所支持。博格达山与准东的关系为背斜北翼与盆地平缓基底构成的挠曲构造 ,而不是被深大断裂分隔的断块。博格达山具有独特鲜明的分段性 ,造山带的两个弧形构造与新生代再生前陆盆地构成独特的“斜方对称”分布样式。以板条观点为指导 ,从盆山单元的平面配置关系和深浅构造转换关系入手 ,探讨了博格达山板内造山阶段的几何学和运动学分段性的成因 ,构建了盆山耦合模式     

燕山造山带构造变形格局研究及相关问题

燕山造山带具有极其复杂的地质结构构造，其复杂性在现有公开出版的地质图件中未能有效地反映出来。从事地学研究的科研人员，以公开出版的地质图件为基础所衍生的相关分析图件和由此作出的结论与野外实际地质情况往往相去甚远。本文作者近年来所做基础地质调查成果显示，基础地质调查成果的缺陷成为制约国家地学科研发展的严重障碍。影响基础地质调查成果质量提高的原因很多，但较为重要的是国家对基础地学科研资金的政策性投入存在问题。     

STRUCTURAL GEOLOGY

正20141283 Bai Daoyuan(Hunan Institute of Geological Survey,Changsha 410016,China);Zhong Xiang Nature,Origin and Tectonic Setting of Jinzhou Basin in the South Segment of Xuefeng Orogen(Geology in China,ISSN1000-3657,CN11-1167/P,40(4),2013,p.1079-1091,10 illus.,47 refs.)Key words:foreland basins,strike-slip faults,Hunan Province     

A long‐lived metamorphic history in the contact aureole of the Mooselookmeguntic pluton revealed by in situ dating of monazite grains preserved as inclusions in staurolite porphyroblasts

Emplacement of the Mooselookmeguntic pluton, located in the western Maine region of the northern Appalachians, was thought to have occurred towards the end of the Acadian deformation at around 370 Ma. Crystallization ages from different parts of the pluton suggest a more sequential emplacement history over a period of c. 20 Myr. Foliation inflection/intersection axes (FIAs) within porphyroblasts from its aureole reveal at least five periods of garnet and staurolite growth. The orientation of FIAs in both garnet and staurolite porphyroblasts trend successively from ESE–WNW, NNW–SSE, E–W, ENE–WSW to NE–SW. Electron probe microanalysis dating of monazite grains included in staurolite porphyroblasts containing one of these five periods of FIA development reveals a succession of apparent ages from 410 Ma to 345 Ma. A similar spread of crystallization ages can be observed for plutons from Maine and adjacent regions. This succession indicates that deformation and metamorphism began well before and continued long after what is classically regarded as the Acadian orogeny. The thermal structure of the orogen progressively evolved to enable pluton emplacement, and it continued to develop afterwards with magmatic fluids still forming at depth.     

湘西合仁坪金矿床硫、铅同位素地球化学

湘西柳林汊一带广泛分布钠长石_石英脉型金矿,合仁坪金矿床是其典型代表。文章对合仁坪金矿床的硫、铅同位素进行了研究,并与区域石英脉型金矿床进行对比,探讨了该矿的成矿物质来源,并初步确定了其矿床成因。研究表明,合仁坪金矿床硫化物的δ34S值范围较窄(-4.8‰~4.4‰),平均为-0.6‰,该矿床的硫为深源硫,由深部变质流体带入;铅的同位素组成较均一,并表现出明显的造山带铅的特点。结合区域成矿作用,进一步研究揭示,合仁坪金矿床为一典型的造山型金矿,其成矿可能与湘西雪峰山地区加里东期的造山作用有关。