陕西凤县八卦庙金矿床特征及采矿方法探讨   总被引：3，自引：1，他引：3  

陈建文  张选固  徐四水  黄长青  刘平 《陕西地质》2003,21(2):27-32

通过八卦庙金矿床地质特征的分析，结合矿山生产实际探讨了采矿方法，认为应实行坑采与露采相结合，可充分利用资源延长矿山寿命，生产安全也优于单一的坑采方法。  相似文献   

甘孜-理塘结合带中部花岗岩的地质特征     

魏永峰  罗森林 《四川地质学报》2003,23(1):5-9

对处于甘孜-理塘结合带中心部位的花岗岩，前人依据其产出的构造背景认为它是结合带的一部分，为多期构造-岩浆活动的产物。本次区调通过岩石学、岩石化学、地球化学和锆石U-Pb内位素年龄测定测定值的研究，确定该花岗岩形成于燕山期，隶属于义敦岛弧花岗岩浆带，后构造推覆定位。  相似文献   

中国北方农牧交错带生态环境的空间格局演变   总被引：1，自引：0，他引：1  

蒋卫国  李京  李加洪  CHEN Yunhao  Wu Yongfeng 《地理学报(英文版)》2005,15(3):329-336

1 IntroductionThe scope of the farm ing-pastoral region of northern China begins from the w est of G reatH inggan M ountains, w estw ards passes through southeastern Inner M ongolia, northern H ebei,Shanxiand Shaanxi,and then reaches the O rdos Plateau.It…  相似文献   

Clinopyroxene phenocrysts (with green salite cores) in trachybasalts: implications for two magma chambers under the Kokchetav UHP massif, North Kazakhstan     

Yongfeng Zhu  Yoshihide Ogasawara 《Journal of Asian Earth Sciences》2004,22(5):517

Clinopyroxene phenocrysts in the Kokchetav trachybasalts are variable in composition and textures. Two distinctive cores are recognized: diopside cores and green salite cores. The diopside cores with Mg# of 80–90 are mantled by colorless salite rims with Mg# of 70–80. The green salite cores have especially low Mg# (<70) but high Al and Ti contents. A Mg-rich band (Mg#=82–90) usually occurs between a green salite core and its rim, and/or between a colorless salite mantle and its rim. Dissolution surfaces are observed on all textural variants. Two magma chambers are needed to explain the observed clinopyroxene phenocrysts. A deep chamber at about 120 km in the upper mantle in which diopside cores crystallized, and a shallow chamber at depths of less than 40 km in which diopside cores were resorbed and overgrown by salite rims or mantles. Magma mixing in the shallow chamber is responsible for the formation of dissolution surfaces between the diopside bands and the colorless salite mantles. The dissolution surfaces on the diopside cores formed in the shallow chamber as a result of pressure decrease. This magma evolution scenario is complicated by the occurrence of the crustal-origin green salite cores in diopsides. These green cores likely represent the relics of continental materials, which were captured in the deep chamber and partially re-melted. Our observations indicate that subducted continental materials were returned to the Earth's surface as a result of magmatism. This study therefore provides direct evidence of a link between subducted continental materials (slab) and magmatism in this orogenic belt.  相似文献   

Re-Os age for molybdenite from the Gangdese porphyry copper belt on Tibetan plateau: Implication for geody- namic setting and duration of the Cu mineralization     

HOU Zengqian  QU Xiaoming  WANG Shuxian  DU Andao  GAO Yongfeng & HUANG Wei . Institute of Mineral Resources  Chinese Academy of Geological Sciences  Beijing  China  . National Center of Geoanalysis  Chinese Academy of Geological Sciences  Beijing  China  . Shijiazhuang College of Economy  Shijiazhuang  China  . Xizang Bureau of Geology  Mineral Resources  Lhasa  China 《中国科学D辑(英文版)》2004,47(3)

It is recognized that there are at least two sorts of significant environments for porphyry copper deposits, i.e. magmatic arcs and collisional orogens[14]. The deposits in the former environments are exampled by the circle-Pacific porphyry copper belt, such as An-dean-type deposits, which mainly formed in the period of the Andean tectonic cycle characterized by trans- pressional and transtensional movements along the arc-parallel strike-slip fault zone in the Late Eo-cene-Early Oligocene[5…  相似文献   

青藏高原东缘新生代构造层序与构造事件   总被引：28，自引：7，他引：28       下载免费PDF全文

李　勇侯中健  司光影Ａ．Ｌ．Ｄｅｎｓｍｏｒｅ 周荣军 Ｍ．Ａ．Ｅｌｌｉｓ李永昭  梁兴中 《中国地质》2002,29(1):30-36

新生代龙门山前盆地和盐源盆地是青藏高原东缘龙门山－锦屏山冲断带内及前缘地区发育和保存最好的新生代沉积盆地，本次以地层不整合面和ESR测年资料为主要依据，将该区新生代构造地层序列划分为5个构造层序，即TS1（65－55Ma)、TS2(40-50Ma)、TS3（23－16Ma)、TS4(4．7-1.6Ma)和TS5（0．74－0Ma)，据此将青藏高原东缘新生代构造变形和隆升事件划分为5期，其中TS1与喜马拉雅地体和拉萨地体拼合事件相关，TS2与印亚碰撞事件相关，TS3与青藏高原第一次隆升事件相关，TS4与青藏高原第二次隆升事件相关，TS5与青藏高原第三次隆升事件相关。  相似文献   

空间地图投影分类研究   总被引：3，自引：0，他引：3  

任留成  施全杰等 《测绘学院学报》2002,19(3):230-231

为了进一步完善空间地图投影的系统理论，对空间地图投影进行了科学分类，主要是借鉴静态地图投影的分类研究成果，介绍按4种不同投影性质对空间地图投影进行科学分类的方法。  相似文献   

莺歌海盆地DF1-1底辟断裂系统及其对天然气成藏的控制   总被引：4，自引：1，他引：4  

殷秀兰  李思田等 《地球科学》2002,27(4):391-396

莺歌海盆地的巨厚充填，高地温梯度及大规模的超压流体活动等特殊的地质背景，造就了DF1－1底辟构造的独特性，其内天然气的总体特征与底辟区的断裂系统存在着密切的联系。底辟区内的超压流体活动使其上覆地层产生众多的断裂和裂缝。这些垂向上的断裂和裂隙既构成了异常压力体系能量释放的主要通道。同时也形成了天然气运多的垂向输导体系。在断裂开启过程中上升的活动流体主要取决于断裂下延的深度及断裂上延所连通的中深一浅层的渗透性砂体，因此由断裂与砂体的相互配置所构成的输导体系在DF1－1气田的成藏中起着重要的作用。根据DF1－1的成藏特点，强调断裂系统与天然气运聚的相互促进关系，建立了断裂系统与天然气成藏关系模式。  相似文献   

张北地震区的断裂构造特征   总被引：5，自引：0，他引：5  

蔡华昌  张四昌  张振江  刘玉枝  任俊峰  何春贵  张启富  刘真友 《华北地震科学》2002,20(2):1-9

1998年1月10日张北6．2级地震发生在张家口坝上地区，震区被中、上新世溢流玄武岩覆盖，第四系地层0－3m。电磁波遥感探测结果表明，张北震区存在NEE、NWW和NE向三组断裂。野外调查证实NWW向的小水泉－－满井断裂，尚义县套里庄乡东水泉南北向断裂和赤城－－尚义大断理解的东西向次级断裂都明显错断中、上新世玄武岩及其夹层。热释光（TL）年龄测定结果表明，这三条断裂的最新活动时代分别为16．7万年，20．3万年和14．3万年。张北地震发生在NEE、NE和NWW向三组断裂的交汇区附近，NWW向的小水泉－－满井断裂是发震断裂。  相似文献   

A numerical experimental study of some dynamical effects on Southern Asiatic High     

Si Gongwang  Donald R. Johnson 《大气科学进展》1985,2(2):133-146

Using a barotropic, steady and linearized vorticity equation and using 250 hPa observed basic flow and global divergence field from the active summer monsoon phase (00 GMT 26 June－12 GMT 29 June) 1979, the dynamical effects of linear absolute vorticity advection, vorticity generation due to divergence and vorticity dissipation due to frictional damping have been tested to understand their influence on Southern Asiatic High (SAH). The key experimental results are: (1) The SAH, one of the major planetary-scale disturbances, is generated from the upper basic flow by the forcing of the upper tropospheric divergence over southeast Asia during the active summer monsoon phase. (2) Linear absolute vorticity advection and frictional damping of vorticity play an important role in the determination of the location of the SAH. (3) The destruction and recovery of planetary-scale geostrophic balance is an important mechanism for the west-east oscillation of the SAH.  相似文献