新疆西天山东段航磁推断断裂构造特征   总被引：2，自引：1，他引：1  

张玄杰  郑广如  范子梁  宋燕兵  张婉  温世新 《物探与化探》2011,35(4):448-454

在最新的高精度航磁图上,新疆西天山东段存在3条磁场特征十分显著深大断裂,它们不仅是区内重要的构造分界线,也是重要的控矿构造带.笔者以西天山东段最新高精度航磁资料为依据,论述了区内深大断裂的磁场特征,并根据航磁资料解释和实际应用结果对深大断裂与成矿的关系进行了探讨.区内沿着深大断裂分布有4处已知的大中型铁矿.根据最新航磁...  相似文献   

Zircon U-Pb ages and Hf isotopic characteristics of the Dehe biotite monzonitic gneiss pluton in the North Qinling orogen and their geological significance   总被引：1，自引：0，他引：1  

LEE Ben 《中国地球化学学报》2011,30(2):204-216

The Dehe granitic pluton intruded the Xiahe Group which is in the core complex of the North Qinling Orogenic Belt(NQOB).It shows gneissic bedding and possesses typical S-type granite minerals such as muscovite and garnet.LA-ICP-MS U-Pb isotopic dating of the Dehe granite yielded a weighted average age of 925±23 Ma which represents the emplacement age of the pluton.Most of the εHf(t) values are negative,and the two-stage model ages are consistent with the age of the Qinling Group.The isotope data show that the Dehe granite was formed in the following geological setting:in the syn-collision setting of the NQOB in the Neoproterozoic,crustal thickening induced partial melting of materials derived from the Qinling complex,and then the maga upwelled and intruded into the Xiahe Group.The formation of the Dehe S-type granite implied the occurrence of a convergent event in the QOB during the Neoproterozoic.  相似文献   

Re–Os and U–Pb Geochronology of the Erlihe Pb–Zn Deposit, Qinling Orogenic Belt, Central China, and Constraints on Its Deposit Genesis     

ZHANG Fan  LIU Shuwen  LI Qiugen  SUN Yali  WANG Zongqi  YAN Quanren  YAN Zhen 《《地质学报》英文版》2011,85(3):673-682

The Erlihe Pb–Zn deposit is an important mine of the Pb–Zn metallogenic zone in the South Qinling Orogen. It has been considered a sedimentary exhalative deposit in previous investigations because the ore body occurs concordantly at the transitional location of an upright fold. Re and Os isotopic analyses for paragenetic pyrites with sphalerite and galena from the ore body have been used to determine the timing of mineralization and to trace the source of metallogenic materials. The Re–Os isotopic data of four pyrite samples construct an isochron, yielding a weighted average age of 226±17 Ma (mean square weighted deviation=1.7), which is considered the main mineralization age. A dioritic porphyrite vein sample, showing weaker mineralization, was also dated using the SHRIMP zircon U–Pb isotopic method to constrain the youngest metallogenic age of the ore deposit, because it distributes along a group of tensional joints cutting not only the upright fold in the deposit field, but also the main ore bodies. The dioritic porphyrite sample yields a weighted mean 206Pb/238U age of 221±3 Ma, which is slightly younger than the Re–Os isotopic isochron age of the pyrites, considered as the upper age limit of the mineralization, namely the ending age of the mineralization. The Os isotopic compositions of sulfide minerals distribute within a range between Os isotopic compositions of the crust and the mantle, indicating that the ore deposit can be derived from magma-related fluid, and the metallogenic materials are most likely derived from the mixing source of the crust and the mantle. The Erlihe Pb–Zn deposit and associated dioritic porphyrite vein, important records of Qinling tectonic–magmatism–mineralization activities, were formed during the Triassic collisional orogeny processes.  相似文献   

山西新发现大理岩玉的宝石矿物学特征     

刘云贵  陈涛  李奇  肖姗 《地质科学译丛》2011,(2):13-19

山西北部六棱山地区新发现了一种玉石品种——大理岩玉,其主要有黄色和黄褐色两种颜色,结构较致密,透明度较好,是一种优质的饰面石材和玉雕原料。采用薄片观察、环境扫描电子显微镜、X射线粉末衍射、LA-ICP-MS和常规宝石学仪器等测试手段对该大理岩玉样品的宝石矿物学特征进行了测试与研究。结果显示,该大理岩玉为经变质作用形成的方解石大理岩,所含CaCO3的质量分数为96%～97%,推测Fe元素是该玉石的致色元素;微量的碳质和铁质粉末阻碍了柱状方解石的重结晶,形成条纹结构;方解石为不规则的多边形柱体,呈镶嵌的不规则他形变晶结构。通过分析大理岩玉的结构特征,认为平行于其层纹方向切磨,可使得其成品表面光洁度好,光泽强,不易破损。  相似文献   

Monitoring Glacial Shrinkage Using Remote Sensing and Site-Observation Method on Southern Slope of Kalik Mountain, Eastern Tian Shan, China     

王文彬  李开明  高建芳 《中国地质大学学报(英文版)》2011,(4)

Currently, one of the effective means in monitoring glacier change in regional scale is remote sensing and site-observation method. In this article, we present a study of comparing glacier area in 2005 derived from SPOT5 satellite image with area in 1972 derived from topographic maps. Moreover, Miaoergou (庙儿沟) flat-summit glacier is site observed to verify glacial change in regional scale. During the study period, glaciers located in the southern slope of Kalik (喀尔里克) Mountain re-duced their area by 12.3%. ...  相似文献   

甘肃天水夏家坪金矿地质特征          下载免费PDF全文

牛浩斌  丁俊  范文玉  廖震文  杨波 《沉积与特提斯地质》2011,31(1):94-99

夏家坪金矿位于西秦岭反＂S＂弧形构造东段Au-Ag-Cu-Fe-Pb-Zn成矿带中,矿体产出受下古生界李子园群沉积-火山岩系控制。矿体多呈带状、透镜状产出,具收缩膨大、尖灭再现及分支复合特征。容矿岩石主要为变砂（泥）岩、破碎石英脉、硅化角砾岩等。矿石类型以构造蚀变岩型为主,局部为石英脉型。围岩蚀变具分带性,矿化可分为早期的金和晚期的银铅锌两个主要成矿阶段。  相似文献   

祁连山冻土区天然气水合物科学钻探试验井中侏罗统的沉积学特征   总被引：1，自引：0，他引：1  

庞守吉  苏新  杨旭  王平康  李永红  郭星旺  李清海 《地质通报》2011,(12)

对青海祁连山冻土区天然气水合物钻井(DK-3)岩心进行了沉积学分析。根据对钻井地层特征、粒度、矿物含量的综合分析,在DK-3钻井揭露的中侏罗统中识别出4种沉积相类型,并完成了沉积微相的划分。伴随地层由老到新,沉积环境由最初发育的辫状河过渡到相对稳定的湖泊(辫状河→湖泊→曲流河三角洲→湖泊)。在133~156m和225.1~240m井段的岩层中发现的天然气水合物,主要呈薄层状分布于岩石裂隙面上;而在367.7~396m井段,天然气水合物除存在于岩石裂隙中外,在砂岩孔隙中亦大量存在。天然气水合物的产出与沉积环境、构造条件有着密切的联系。  相似文献   

祁连山冻土区天然气水合物烃类气体组分 的特征和成因   总被引：6，自引：1，他引：5  

黄霞  祝有海  王平康  郭星旺 《地质通报》2011,30(12):1851-1856

祁连山冻土区天然气水合物DK-2科学钻探试验孔水合物储集层岩心气样的烃类气体组分和C同位素分析测试结果表明,祁连山冻土区天然气水合物烃类气体组分复杂,除甲烷外,还含有较高的乙烷和丙烷;δ13C1均大于-50‰,R值普遍小于100,显示出明显的热解气特征。结合钻探区的地质背景和岩性特征,初步判断气体大多来源于深部迁移上来的油型气,并有部分原地煤成气的混合。  相似文献   

青海祁漫塔格山乌兰乌珠尔斑状正长花岗岩 LA-MC-ICPMS锆石U-Pb定年及地质意义   总被引：5，自引：2，他引：3  

郭通珍  刘荣  陈发彬  白旭东  李红刚 《地质通报》2011,30(8):1203-1211

青海祁漫塔格地区乌兰乌珠尔正长花岗岩具有高硅、高碱(AR为3.02~5.88,NK/A为1.04~1.17,A/CNK为0.96~1.07)、高TFeO/MgO和贫CaO、MgO的特征;∑REE较高,LREE略富集,轻重稀土元素分馏不十分明显,Eu负异常明显,稀土元素配分模式呈稍右倾的V字形;明显富集Rb、K、Th等大离子亲石元素,相对富集Zr、Hf等高场强元素,相对亏损Ba、Sr、P、Ti、Nb等。这些资料显示了A2型铝质花岗岩的特征,其来源可能与洋壳、岛弧建造组成的年轻地壳有关。采用LA-MC-ICPMS锆石U-Pb定年方法,获得乌兰乌珠尔正长花岗岩体的206Pb/238U年龄为388.9Ma±3.7Ma(MSWD=3.1),代表该岩体的形成年龄。结合岩石地球化学、构造特征和区域地质背景,认为该岩体形成于后造山或造山作用演化晚期相对伸展的环境。  相似文献   

大兴安岭幔枝构造与银多金属成矿作用   总被引：3，自引：0，他引：3  

牛树银  聂凤军  孙爱群  江思宏  王宝德  张建珍  马宝军  白大明  陈超 《吉林大学学报(地球科学版)》2011,41(6):1944-1958

通过对大兴安岭地区构造演化、区域地质、地球物理、地球化学特征的研究,认为燕山期以来是该区地幔热柱强烈活动时期.最明显的表现是强烈的构造运动和大规模的岩浆活动,最显著的标志是兴蒙地区盆岭构造的形成和大规模的成矿作用.大兴安岭中南段是一较典型的幔枝构造,具有明显的核部岩浆-变质杂岩、外围拆离滑脱层及上叠断陷盆地,是该区重要...  相似文献