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41.
鄂东南地区铜山口花岗闪长斑岩体是与斑岩铜钼矿床共生的岩体,但殷祖花岗闪长岩体是与金属成矿无关的岩体。铜山口和殷祖侵入岩的元素地球化学特征与埃达克岩的地球化学特征非常类似,如高Al2O3、Sr含量与La/Yb、Sr/Y比值,富Na2O(Na2O/K2O>1.0),亏损Y与Yb,极弱负Eu异常-正Eu异常以及正Sr异常等。但是铜山口和殷祖侵入岩也存在 明显的差别:前者比后者更偏酸性,但具有较高的K2O,MgO,Cr,Ni和Sr含量,较低的Y和Yb含量,轻重稀土元素分异更明显,并主要显示出正铕异常,区别于后者的极弱负Eu异常-不明显Eu异常。这表明铜山口埃达克质侵入岩的岩浆来源可能比殷祖埃达克质侵入岩的岩浆来源更深:前者可能由拆沉的下地壳熔融形成,残留物主要含石榴子石;而后者可能由增厚的下地壳熔融形成,残留物可能为石榴子石±斜长石±角闪石。另外,热的地幔上涌,底辟(diapir)进入下地壳,导致含角闪石的榴辉岩发生熔融也可形成铜山口埃达克质岩浆。铜山口埃达克质岩浆在穿过地幔的过程中,将会与地幔橄榄岩发生交换反应:一方面由于受橄榄岩的混染而使得岩浆的MgO,Cr和Ni增高;另一方面岩浆中的Fe2O3不断加入到地幔中,导致地幔的氧逸度(fo2)增高,地幔中金属硫化物被氧化并进入岩浆中,富含Cu-Mo等成矿物质的岩浆上升很容易形成斑岩铜钼矿  相似文献   
42.
青藏高原东缘古近纪粗碎屑岩沉积学及其构造意义   总被引:10,自引:0,他引:10       下载免费PDF全文
青藏高原东缘古近纪盆地的填图和沉积学研究表明,在青藏高原东缘区域性走滑-挤压构造背景下形成的古近纪盆地内广泛发育厚层—巨厚层状的紫红色粗碎屑岩系。其沉积特征指示为一种近源快速堆积的泥石流和辫状河道沉积体,形成于干旱炎热气候条件下的典型陆内冲积扇环境。盆地充填序列、粗碎屑岩层序、动植物化石和盆地内岩浆岩~(40)Ar-~(39)Ar年代学等综合研究结果表明,古近纪盆地内粗碎屑岩大约形成于38~29 Ma。该时期与青藏高原东缘北段(横断山地区)古近纪盆地的形成和南段(兰坪—思茅地区)大盆地的裂解时间基本一致,这很可能预示着青藏高原在晚始新世—早渐新世期间曾发生过整体的快速构造隆升。  相似文献   
43.
洪江 《贵州地质》2003,20(1):56-59
为矿产勘察开发提出完整可靠的选矿验证,资源量验证及岩土力学原始资料,引进三套管(NQ3)取心工艺并进行了应用试验,重点介绍了该工艺的原理以及在金矿勘查60°斜孔施工中的应用.  相似文献   
44.
In order to constrain the crustal wave velocity structure in the southern Tibetan crust and provide insight into the contribution of crustal composition, geothermal gradient and partial melting to the velocity structure, which is characterized by low average crustal velocities and widespread presence of low-velocity zone(s), the authors model the crustal velocity and density as functions of depth corresponding to various heat flow values in light of velocity measurements at high temperature and high pressure. The modeled velocity and density are regarded as comparison standards. The comparison of the standards with seismic observations in southern Tibet implies that the predominantly felsic composition at high heat flow cannot explain the observed velocity structure there. Hence, the authors are in favor of attributing low average crustal velocities and low-velocity zone(s) observed in southern Tibet mainly to partial melting. Modeling based on the experimental results suggests that a melting percentage  相似文献   
45.
对鄂东地区上泥盆统五通组砂岩的成因,一直存在河流相和滨海相的不同认识。野外研究和室内分析表明:该组主要为一套成熟度较好纯净的石英砂岩和含海绿石石英砂岩。概率累积曲线斜率较大,以跳跃组分为主,悬浮组分和滚动组分含量低,有的砂岩跳跃组分具两段式,粒度参数属于分选好的滨海砂范围。微相和粒度分析都表明其具有明显的高能碎屑海岸的滨海沉积特征。砂岩中发育大型冲洗交错层理、大型不对称浪成波痕、不规则的坑凹面等典型的海滩沉积构造。纵向上为临滨下部一临滨上部一临滨下部一临滨上部一前滨一后滨沉积特征,上部为一个完整的退积型海滩沉积序列。区域古地理分析反映下扬子的鄂东地区晚泥盆世时期处于滨浅海环境,其北部可能与秦岭古海洋相通。  相似文献   
46.
老林沟石榴石矿产于黄陵背斜北部类孔兹岩系中一套富铝铁质正常沉积的泥质粉砂岩、泥质岩中,在区域热动力变质作用下,铁铝榴石与夕线石共生,属于巴罗变质系列中夕线石带产物,根据矿物共生组合、指相特征矿物得出形成该矿产的区域变质的温压条件为:t为7 00℃,P为7 30MPa,变质相属低角闪岩相至高角闪岩相。  相似文献   
47.
Different scales of structural data reveal a complex deformation history of ultrahigh- pressure (UHP) rocks exposed in the Weihai-Rongcbeng area, NE Sulu (northern Jiangsu-eastern Shandong), eastern China. Excluding pre-UHP deformations, at least five major sequential deformational stages (D1-Ds) are recognized. The first deformation (DO produced a weak foliation and lineation in massive eclogites. The foliated eclogite with a dominant foliation containing a stretching and mineral lineation was developed during the I)2 deformation. Both the D1 and D2 deformations occurred under UHP metamorphic conditions, and are well preserved in the eclogite bodies. D3 structures which developed shortly after the formation of granulite/amphibolite facies symplectites are characterized by imbricated associations marked by a regional, steeply dipping foliation, compositional layering, eclogite boudinage, isoclinal folds and reverse ductile shear zones. The D3 deformation was accompanied by decompressional partial melting. A regional, gently dipping amphibolite facies foliation and stretching lineation, low-angle detachments, and dome- and arc-shaped structures formed during the D4 deformation stage dominate to some degree the map pattern of the Weihai-Rongcbeng UHP domain. The last stage of deformation (Ds) gave rise to the final exhumation of the UHP rocks. Ds is characterized by development of brittle-dominated high-angle faulting associated with emplacement of large volmnes of undeformed granite plutons and dykes dated at 134-100 Ma. The deformational and metamorphic sequence followed by the UHP rocks in the Weihai-Rongcheng area is similar to that studied in the entire Dabie-Sulu UHP and HP metamorphic belts from microscopic to mapping scale. Based on structural data, combined with available petrographic, metamorphic and geochronological data, a speculative tectonic evolutionary model for the Dabie-Sulu UHP and IIP belts is proposed, involving continental subduction/collision between the Sino-Korean and Yangtze cratons and subsequent polyphase exhumation histories of the UHP and IIP metamorphic rocks.  相似文献   
48.
1 Introduction The Songpan-Zoigê Block (SRB) lies in the east of the Qinghai-Tibet Plateau. It is a triangle block confined and surrounded by three structure belts: the east Kunlun-west Qinling belt (EK-WQLB) to the north, the Sichuan Basin to the southeast and the Garzê-Litang-Jinsha River belt to the southwest. This block is also the joint part of three tectonic domains: the North China, South China and Qinghai-Tibet domains (Huang and Chen, 1987). The development and evolutio…  相似文献   
49.
The Ordos Basin is well-known for the coexistence of oil, natural gas, coal and uranium. However, there has been little research to discuss the genetic relationship between them. In this paper, a case study of the Zaohuohao area in Dongsheng, Inner Mongolia, China, is conducted to investigate the genetic relationship between the natural gas and the uranium accumulation. Fluid inclusion data from the uranium-bearing sandstone samples indicate that the fluid inclusions formed in a gas-water transition zone. Using the homogeneous temperatures of aqueous inclusions coeval with hydrocarbon-bearing inclusions, combined with the buried history and paleo-temperature data, the gas-water transition zone reached the area at about 110 Ma. On the basis of this, the contents of Uranium (U) and Total Organic Carbon (TOC) of the samples were analyzed, and there was no obvious relation between them. With regard to the available data from both publications and this study, it is found that the U mineralization has a spatiotemporal accordance with the gas-water dispersal zone. Thus, it is believed that the natural gas in the gas-water zone is an effective reducer to the U-bearing ground water abundant in oxygen, which is the main factor to U accumulation. This result can be used as the reference to the U mines predicting and prospecting.  相似文献   
50.
地理信息系统(GIS)是处理空间数据的软件系统,其基本模块包括空间数据的组织、查询、可视化及空间关系分析与决策支持,主要功能为空间数据的获取、管理、分析及可视化表达。作为地理信息科学的重要组成部分,地理信息系统在社会生活的各领域已得到了越来越广泛的应用,它的广泛应用为油气勘探开发研究中的古构造重建、储层研究、油气运移路径分析及资源评价等提供了新的信息处理辅助手段和工具。本文分析了地理信息系统在油气勘探开发中的地位和作用,详细介绍了它在油气勘探开发中的应用的历史和现状,并结合当前地理信息系统领域的研究热点和油气勘探开发研究的实际,探讨了其在油气勘探开发领域应用的前景及发展方向。  相似文献   
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