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1.
长江中下游成矿带铜陵矿集区铜多金属矿床模型   总被引:49,自引:6,他引:43       下载免费PDF全文
通过对长江中下游成矿带的系统考察和对前人资料的阅读和研究,聚焦铜陵矿集区,初步提出了一个可以涵盖不同类型矿床的矿床模型.该模型表达为:在早白垩世高钾钙碱性花岗岩侵位过程中,通过岩浆的分馏演化,在岩体隆起部位及其内外接触带形成斑岩-矽卡岩型矿床,由于广泛发育石炭纪至三叠纪碳酸盐岩.钙质和镁质矽卡岩型矿床是最主要的矿床类型.作为斑岩-矽卡岩型矿床系统的一部分,在斑岩-矽卡岩铜金钼矿床外围分布有矽卡岩铜金矿床、脉状金矿床以及脉状铅锌银矿床.长江中下游地区在三叠纪曾作为大别-苏鲁造山带的前陆盆地,在后碰撞时期出现了大量滑覆构造和扩容空间,它们在不整合界面处十分发育.因此,在成矿过程中不仅形成了像新桥那样的厚大矿体,而且在位于不整合界面附近的矽卡岩往往退化蚀变成为具有典型层纹状和曲卷状构造的退化蚀变岩和矿石,甚至沿一些层位交代形成了层控矽卡岩型或Manto型矿体.此外,还提出了运用该模型开展勘查评价的建议.  相似文献
2.
冬瓜山铜(金)矿床中主矿体成层状,受石炭系层位控制,对于其物质来源尚存在较大分歧。为了查明冬瓜山铜(金)矿床成矿物质来源,本文对冬瓜山铜(金)矿床不同类型矿体的氢、氧、硫、铅同位素进行了系统地测定。并将冬瓜山铜(金)矿床与铜陵矿集区内典型矽卡岩型矿床的硫、铅同位素组成进行了对比研究。结果表明:冬瓜山铜(金)矿床不同类型矿体之间具有相同的物质成分来源,不同类型矿体的成矿流体主要来源于岩浆水,硫源均为岩浆硫,且与区域上典型矽卡岩型矿床的硫同位素组成一致,铅同位素特征表明,不同类型矿体铅的来源主要为与岩浆作用有关的幔源铅。  相似文献
3.
滇西南墨江金厂金镍矿床金、镍赋存状态及成矿过程探讨   总被引:2,自引:2,他引:0  
墨江金厂金镍矿床位于滇西南哀牢山造山带中段,是西南三江地区一个独特的金镍共生矿床。笔者通过野外地质观察,并结合室内显微镜下观察和电子探针分析手段,对矿区矿石中的金、镍矿物进行了研究。结果显示金厂矿床金的赋存形式主要为可见金和不可见金。其中可见金又有两种赋存状态:(1)粒间金(赋存在中细粒石英脉中的自然金颗粒);(2)包体金,主要被硫锑铜银矿包裹。而不可见金是以Au+形式赋存于黄铁矿中。含金矿物主要为自然金、黄铁矿、毒砂等。镍的赋存状态有两种:(1)以独立矿物,如针镍矿、辉砷镍矿及锑硫镍矿存在;(2)以离子态赋存于黄铁矿、毒砂等矿物中。含镍矿物主要为针镍矿、辉砷镍矿、锑硫镍矿、黄铁矿等。依据矿(化)脉切割关系、矿石结构构造及矿物共生组合,墨江金厂金镍矿床成岩-成矿期共发育4个世代黄铁矿。沉积变质期以草莓状黄铁矿和胶状黄铁矿为主,热液成矿期可划分为:早阶段石英-针镍矿-辉砷镍矿-锑硫镍矿-黄铁矿;主阶段石英-黄铁矿-毒砂-硫锑铜银矿-自然金;晚阶段方解石-石英-黄铁矿。对矿区赋金镍贯通性矿物黄铁矿进行详细的电子探针分析,结果显示4个世代黄铁矿微量元素有所差异。其中热液主阶段黄铁矿中含有Au、As、Sb、Pb、Zn、Cu、Co、Ni和Te,显示其流体成分复杂。不同阶段黄铁矿Ni含量不同,沉积变质期黄铁矿中Ni含量较低,为0.00%~0.82%,平均0.26%;热液早阶段黄铁矿中Ni含量最高,为0.43%~3.15%,平均1.38%;热液主阶段黄铁矿中Ni含量降低,为0.00%~0.99%,平均0.22%;热液晚阶段黄铁矿中Ni含量最低,为0.00%~0.09%,平均0.03%。研究结果表明墨江金厂金镍矿床中主要含金矿物和含镍矿物形成于热液期,含金矿物形成晚于含镍矿物。Ni在热液流体中的迁移能力与流体温度正相关,温度越高,Ni进入黄铁矿晶格的能力越强。基于上述金、镍成矿过程研究成果,并对比国内外热液镍矿床的地质-地球化学特征,推断墨江金厂金镍矿床是一个受岩浆热液改造的中-低温热液金镍矿床。  相似文献
4.
凤凰山铜矿床两类成矿岩体的厘定及其成因分析   总被引:2,自引:2,他引:0  
本文从地质、地球化学以及矿化蚀变特征等方面对凤凰山矿田内两类不同成矿岩体的特征进行了对比,指出凤凰山复式岩体由早期的花岗闪长岩和晚期的石英二长闪长斑岩所组成,与花岗闪长岩有关的成矿作用主要为矽卡岩型成矿作用,与石英二长闪长斑岩有关的成矿作用主要为斑岩型成矿作用.并对新发现的斑岩型矿化的大地构造背景、围岩、蚀变特征、控矿构造以及矿石类型进行了阐述.最后,在综合分析成矿物质来源、物理化学条件、成矿流体和成矿作用的基础上,对凤凰山铜矿床的成因进行了探讨,认为矿床的形成主要与中酸性岩浆活动有关,经历了多种成矿作用,形成了多种矿化型式,矿床成因属以岩浆热液为主的复合型热液矿床.  相似文献
5.
The Fenghuangshan Pluton is located in the Tongling polymineral-cluster district in the middle-lower section of the Yangtze metallogenic belt. In tectonic terms, it is in the middle of the Guichi-Fanchang faulted fold bundle of the lower Yangtze Platform fold belt between the Dabie Orogenic Belt and the Jiangnan Massif. Analyses of the structural deformation characteristics of both the contact zone and the interior of the pluton are used to explain its emplacement mechanism. The foliation and lineation of the pluton, consisting of the oriented distribution of dark minerals and xenoliths, mainly concentrate along the margin of the pluton. Toward the center of the pluton, the foliation structure becomes weak, showing intense compression formation at the margin, and reflecting the conformable intrusion of the pluton. The relatively gentle lineation is evidence of a rotatory emplacement mechanism. Relatively steep marginal foliation reflects compression expanding. Affected by the thermal power of the pluton,  相似文献
6.
流体包裹体的研究表明冬瓜山铜(金)矿床原生流体包裹体分为气液两相水溶液包裹体(Ⅰ型)和含子矿物多相水溶液包裹体(Ⅱ型),以Ⅰ型包裹体为主。同一矿物中多种类型包裹体共存,且均一温度相近、均一方式不同,显示成矿过程中流体可能发生过沸腾作用。流体包裹体均一温度大致可分为318.8~547.5℃、220.1~378.2℃和196.7~263.2℃三个区间,对应流体密度和均一压力分别为0.86~0.98 g/cm3和(219~661)×105 Pa、0.66~1.08 g/cm3 和(26~190)×105 Pa、0.88~0.96 g/cm3和(17~48)×105 Pa,盐度w(NaCleq)峰值为12%~16%和40%~48%。结合成矿流体的演化特征,对成矿过程进行了探讨,认为流体的不混溶是引起成矿物质沉淀富集成矿的重要因素。  相似文献
7.
Located in the East Qinling molybdenum metallogenic belt on the southern margin of the North China craton, the Nannihu Mo (-W) orefield comprising Nannihu, Sandaozhuang, and Shangfanggou deposits is a superlarge skarn-porphyry Mo (-W) orefield in the world. Re-Os dating was performed of six molybdenite samples from the Mo deposits in the Nannihu Mo orefield with inductively coupled plasma mass spectrometry (ICP-MS). The results show that the Re-Os model ages are 145.8±2.1-141.8±2.1 Ma for the Nannihu deposit, 145.4±2.0-144.5±2.2 Ma (averaging 145.0±2.2 Ma) for the Sandaozhuang deposit and 145.8±2.1-143.8±2.1 Ma (averaging 144.8±2.1 Ma) for the Shangfanggou deposit; dating of the six samples yields an isochron age of 141.5±7.8 Ma (2σ), which accurately determines the timing of mineralization. The results also suggest that the ore-forming materials were mainly derived from the lower crust, mixed with minor mantle components. These Mo deposits were formed during the transition of the Mesozoic tect  相似文献
8.
张宇  邵拥军  全伟  刘忠法  刘清泉 《地质论评》2015,61(5):1168-1176
为了探讨新桥Cu—S—Fe矿床的形成是否经历过海西期海底喷流沉积成矿作用,在详细的野外调研和室内工作基础上,对层状矿体下盘石英黄铁矿脉中的石英流体包裹体进行Rb Sr同位素定年分析。研究结果表明:下盘石英黄铁矿脉中的石英流体包裹体Rb Sr等时线年龄为138.0±2.3Ma(MSWD=5.4),与矶头复式岩株的成岩年龄相近(140.4±2.2Ma),而且下盘网脉状矿化石英流体包裹体中流体的n(87Sr)/n(86Sr)初始值(0.71138±0.00014)和矶头岩株的n(87Sr)/n(86Sr)初始比值相近,说明下盘网脉状矿化为岩浆热液成因,并非为海西期海底喷流通道。与典型海底喷流沉积矿床进行地质特征对比分析也发现,新桥Cu—S—Fe矿床地质特征有别于典型的海底喷流沉积矿床。综合分析认为,新桥Cu—S—Fe矿床应属于燕山期岩浆热液矿床。  相似文献
9.
The Shizitou molybdenum(Mo) deposit in Yongping, Jiangxi, is an important, recently discovered deposit in the eastern section of the Qin–Hang metallogenic belt. The Mo deposit is located in the outer contact zone between the porphyritic biotite granite and the Neoproterozoic migmatite, and present in the deep central part of the intrusion. Re–Os dating and S and Pb isotopic analysis have been conducted to assess the metallogenesis of the Shizitou Mo deposit. S, Pb and Re isotopes show that the ore–forming materials were derived from the porphyritic biotite granitic magma, which originated from the mixing of mantle and crust. Re–Os dating of molybdenite from the ores gives a model age from 156.9±2.2 to 158.5±2.4 Ma, with a weighted mean age of 158±1 Ma and an isochron age of 158.0±2.5 Ma. Geological and geochemical characteristics of the ore deposit and the related granitoids indicate that the Shizitou deposit is a Climax–type Mo deposit. Based on previous studies of the Qin–Hang metallogenic belt, two metallogenic events are believed to have occurred during 172–145 Ma and 137–132 Ma. These two metallogenic periods are consistent with the timing of two metallogenic peaks during the middle to late Jurassic and the Cretaceous in South China. These events represent responses to the partial back–arc extension associated with the subduction of the Izanagi plate beneath the Eurasian continent and the rapid northeastward movement of the subducting Izanagi plate.  相似文献
10.
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