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81.
“战略性新兴产业矿产调查”工程积极倡导绿色调查新理论新方法在大型资源基地勘查开发中的应用,绿色调查是川西大型锂铍资源基地综合调查评价工作的主要内容之一。本文梳理了水化学找矿法的发展历程与现状,提出了水化学找矿法应用于矿产勘查及环境调查评价中存在的主要问题。在川西九龙湿润半湿润高寒山区,尝试应用水化学找矿法对地表水中的化学异常进行研究,初步阐明应进一步详细调查的锂远景区。实验方法是在野外现场运用多参数测试仪测定地表水的温度(T)、pH值、电导率(EC)、溶解氧(DO)、总溶解性固体(TDS)五个参数,结合电感耦合等离子体质谱法(ICP-MS)测定锂硼铷锶镍钨钪等微量元素,进而分析水体元素含量特征与矿化的关系。结果表明:研究区水体中的锂硼锶镍含量明显高于背景值,在采集的60件样品中,17%的样品以上微量元素含量超过异常下限(7.76μg/L),其中流经乌拉溪岩体东南角(石头沟)的水体锂含量达到最大值20.1μg/L,是研究区水体锂含量背景值的4.5倍,是异常下限的2.6倍,与矿化的关系密切,其明显的变化规律可作为水化学找锂的找矿标志。研究区内乌拉溪岩体东南部及洛莫岩体周边水体水化学异常与矿化关系明显,可作为下一步详细调查的远景区。研究认为,在当前环境保护战略地位不断提升、绿色勘查力度持续加大、资源调查与环境保护并重的现实条件下,水化学方法对前期找矿部署有指导意义。研究成果为解决川西高原生态脆弱区找矿部署与环境保护等实际问题提供了参考依据。 相似文献
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英云闪长岩-奥长花岗岩-花岗闪长岩(TTG)是地球早期大陆地壳最重要的组成部分。TTG的Nb/Ta比值变化不仅与它的成因相关,而且与早期构造环境和地壳分异过程关系紧密。本文选择阴山地块出露的TTG片麻岩及下地壳斜长角闪岩/麻粒岩包体作为研究对象,开展了寄主花岗闪长岩和同源镁铁质包体中的角闪石和黑云母的原位微区矿物的微量元素分析工作,以及TTG与非同源斜长角闪岩包体的全岩主微量元素分析工作。矿物化学研究结果表明,花岗闪长岩和同源镁铁质包体的角闪石具有相似的Mg#值,但是两者具有明显不同的Nb/Ta比值。镁铁质包体中的角闪石更富Cr、Ta,Nb/Ta比值为30~50;TTG岩石中的角闪石Cr和Ta含量偏低,但具有更高的Nb/Ta比值(38~70)。TTG和镁铁质包体中的角闪石Cr含量与Nb/Ta具有较好的负相关关系。全岩地球化学分析结果揭示,TTG片麻岩的具有高Nb/Ta比值(13~65,平均值31),斜长角闪岩和麻粒岩包体具有变化的Nb/Ta比值(10~56)。太古宙绿岩带中玄武质岩石的Nb/Ta平均值为~15,阴山地块斜长角闪岩和麻粒岩包体具有高的Nb/Ta比值,反映了这些代表基性下地壳的岩石经历了部分熔融作用或后期的交代作用,使其Nb/Ta比值发生改变。研究区具有高Nb/Ta比值的TTG可能来源于高Nb/Ta比值基性下地壳部分熔融,并继承了源区高Nb/Ta比值的特征。通过本文研究揭示,高Nb/Ta比值的TTG并非一定形成于俯冲带洋壳榴辉岩相部分熔融,下地壳富角闪石和黑云母的岩石部分熔融是形成高Nb/Ta比值TTG的一种重要途径。 相似文献
83.
We studied the sedimentary characteristics of a Paleocene-Eocene salt lake in the Jiangling Depression through field core observation,thin section identification,scanning electron microscopy,and X-ray diffraction analysis.On the basis of sedimentary characteristics we have summarized the petrological and mineralogical characteristics of the salt lake and proposed 9 types of grade IV salt rhythms.The deposition shows a desalting to salting order of halite-argillaceous-mudstone-mud dolostonemud anhydrock-glauberite-halite.The relationship among grade IV rhythms,water salinity and climate fluctuations was analyzed.Based on the analysis of the relationship between boron content and mudstone color and by combining the mineralogy and sedimentary environment characteristics,we propose that the early and late Paleocene Shashi Formation in the Jiangling Depression was a paleolacustrine depositional environment with a high salt content,which is a representation of the shallow water salt lake depositional model.The middle Paleocene Shashi Formation and the early Eocene Xingouzui Formation were salt and brackish sedimentary environments with low salt content in a deep paleolake,which represents a deep salt lake depositional model. 相似文献
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A new 3D geological model and interpretation of structural evolution of the Rio Tinto world-class VMS deposit are presented in this work. The Rio Tinto volcanogenic massive sulfide (VMS) deposit is located in the Spanish segment of the Iberian Pyrite Belt and is hosted by felsic porphyritic volcanic rocks and tuffs. Computer generated 3D modeling of the different orebodies and host rocks has been carried out using data from around 3000 drill-core logs, allowing us to build 93 cross-sections and 6 plants (both 50 m spacing). This has enabled us to recognize the geometry and relationships between the mineralization and the earliest Carboniferous transtensional tectonics through the development of an extensional pull-apart basin with two sub-basins separated by the NW-SE trending Eduardo Fault. The sub-basins, Cerro Colorado and San Dionisio, were limited by two E-W strike-slip faults, the Northern and Southern faults, and bounded in the east and west by the NW-SE-trending Nerva and Western faults, respectively. The generated pull-apart basin was first filled by a basaltic magmatism of mantle origin and later, following the deposition of the intermediate complex sedimentary unit, by rhyodacitic volcanic rocks of crustal origin. The evolution of the subsiding basins caused the development of an E-W oriented rollover anticline that affected these filling rocks.As a result of a counterclockwise rotation of the stress axes, the primitive pull-apart basin evolved into a basin affected by E-W transtensional sinistral shearing. Its northern and southern limits were favorable areas for increased hydrothermal fluid flow, which gave way to the huge concentration of VMS mineralization located near the limits. The Northern and, to a lesser degree, the Southern extensional faults thus become channel areas for feeding and discharging of the VMS and stockwork ores. The main mineralizing period was related to this stage. Subsequently, during the Variscan transpressional phase, the E-W extensional faults were reactivated as inverse faults, affecting the volcanic sequence of mafic to felsic composition and the intermediate complex sedimentary unit. Fault propagation folds developed above these faults, affecting the massive sulfides, the transition series and the Culm flysch sediments, with buttressing playing a significant role in the geometry of tectonically inverted structures. The VMS mineralization and cupriferous stockworks were folded and dismembered from the original conduits in the volcanic series, and a dextral reactivation of the NW-SE trending faults also developed.Finally, it should be emphasized that this new 3D geological model is an approach to provide a better insight into the 3D structure of the world-class VMS Rio Tinto deposit and could be a key-point for further studies providing a new tool to increase knowledge of the VMS mineralizations and exploration guidelines elsewhere in the IPB. 相似文献
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A step-wise numerical calculation method was developed to provide predictions of when and where carbonate deposits might be found through reservoirs during CO2 sequestration. Flow experiments through porous media using a supersaturated carbonate fluid were also performed in order to observe flow rates. In order to evaluate precipitation rates and permeability change in the formation, calculated flow rates based on the proposed geochemical clogging model were compared with the experimentally observed data. Both high and low temperature cases were studied to understand how hydrothermal conditions can affect precipitation rates of carbonate. According to chemical kinetics, growth rates of minerals are generally proportional to the saturation index (S.I.) that depends on temperature. Thus, a supersaturated fluid has the advantage of improving the filtration and the amount of C fixation (σ). However, when the ratio of filtration coefficient (λ) to pore fluid velocity (u) increases, the permeability around the injection point tends to be significantly reduced by carbonate accumulation, and thus, this might result in insufficient injection of CO2. Therefore, it is essential to understand how to control both λ and u so that the precipitation of carbonate can be located as far away from the inlet as possible. 相似文献
87.
川西甲基卡308号脉的矿物学特征及其岩浆- 热液演化示踪 总被引：1，自引：0，他引：1
甲基卡稀有金属矿床是亚洲规模最大的伟晶岩型锂矿床，308号脉为其中出露面积最大的伟晶岩脉。308号脉具有完善的分带性:细粒白云母- 钠长石- 石英带（Ⅰ）、中粗粒钠长石- 石英- 微斜长石带（Ⅱ）、中粒电气石- 钠长石- 石英带（Ⅲ）、中粗粒锂辉石- 钠长石- 石英带（Ⅳ）和中细粒锂辉石- 钠长石- 石英带（Ⅴ），并且富含稀有金属矿物（如锂辉石、绿柱石、锡石和铌钽氧化物），因此是系统研究伟晶岩演化历史和成岩成矿机制的理想实验对象。308号脉的矿物学研究较为薄弱，其岩浆- 热液演化过程及该过程中熔- 流体性质的变化规律，以及稀有金属的富集过程和影响因素尚不清楚。本文选取该脉各结构带中的贯通性矿物云母、磷灰石，以及稀有金属矿物锂辉石和特征性矿物电气石，通过详细的电子探针工作，分析它们的产状、结构特征、化学组成及其变化，结果表明:① 308号脉边部Ⅰ带（高温结晶）中电气石的出现（~5%）反映伟晶岩初始熔体具有富B的特征（>2%）；锂辉石在Ⅳ和Ⅴ带内的大量结晶说明初始熔体可能具有富Li的性质；主要含氟矿物电气石、磷灰石和云母类在岩石中的含量均较低，并且原生磷灰石具有相对偏低的F浓度（<3%），仅能形成于富F环境中的锂云母矿物也十分稀少，这些特征均表明308号脉初始熔体很可能具有较低的F含量；② 伟晶岩体系演化至Ⅴ带时发生流体出溶现象，自此进入岩浆- 热液过渡阶段，出溶流体可能具有富Cs和贫F的性质；③ 原生白云母和电气石化学成分的规律性变化说明308号脉的演化过程很可能不存在外来流体的加入；④ 308号伟晶岩的成岩和锂成矿过程主要受分异结晶作用支配，有限的出溶流体规模和伟晶岩分异演化程度（仅演化至岩浆- 热液过渡阶段，未充分进入热液阶段）对锂辉石的结晶和保存都起到了重要作用。 相似文献
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宁芜玢岩型铁矿矿集区是中国东部重要的铁矿矿集区之一。宁芜矿集区在早白垩世135~126 Ma间连续发育了成分和源区相似的4组火山作用旋回,并伴随有两大类侵入岩发育：一类为辉石闪长玢岩-闪长玢岩,与玢岩型铁矿床的形成密切相关,主要发育于大王山火山旋回晚期（约131 Ma）;另一类为花岗岩类侵入岩,形成于铁矿化之后,成岩时代与姑山和娘娘山火山旋回相近（130~126 Ma）。两类侵入岩源区的差异与联系目前尚未揭露。本次研究通过对两类侵入岩锆石年代学、Hf-O同位素特征的研究,区分了不同侵入岩源区差异。结果表明,与成矿母岩同旋回侵入岩锆石的δ18O集中于6.0‰~6.5‰,εHf（t）集中于-6.0~-5.0;成矿后形成的花岗岩类侵入岩锆石的δ18O集中于7.0 ‰至8.0 ‰,εHf（t）分布于-8.7~-1.2。结合前人研究,区内岩浆活动存在有富集地幔、太古代地壳和新元古代地壳3个岩浆源区,4个火山作用旋回的岩浆源区在130 Ma左右发生了改变。130 Ma之前的龙王山和大王山火山旋回的岩浆岩源区主要为受太古代地壳混染的富集地幔,而130 Ma之后的姑山和娘娘山火山作用旋回的岩浆岩源区主要为受新元古代地壳混染的富集地幔。多阶段火山作用中只有大王山旋回的闪长玢岩与玢岩型铁矿的形成有关。相比较其他火山旋回,大王山旋回具有更高的富集地幔组分以及更少的新元古代地壳的混染。因而,岩浆中较高比例的富集地幔含量是控制玢岩型铁矿形成的关键因素之一。 相似文献
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SHENG Jifu LIU Lijun WANG Denghong CHEN Zhenghui YING Lijuan HUANG Fan WANG Jiahuan ZENG Le 《《地质学报》英文版》2015,89(4):1359-1374
Tungsten ore resources are abundant in China with relatively complete types of deposits. Skarn type and quartz vein type deposits are dominated in the tungsten resources, whereas quartz vein type wolframite deposits are most important in terms of exploitation and utilization. Skarn type tungsten deposits are concentratedly distributed in the central Nanling region, such as South Hunan, South Anhui and the eastern Qinling region, while quartz vein type tungsten deposits occur mainly in South China, such as West Fujian, South Jiangxi, North Guangdong and South Hunan. The most important metallogenic epoch of tungsten is the Mesozoic, while the metallogenic tectonic setting is featured by an intracontinental environment after orogeny with sever tectonic movements, deep-seated faults and frequent magmatic activities, especially Mesozoic granitoids closely related to tungsten-tin mineralization. 22 metallogenic series of ore deposits characterized by or significantly related to tungsten were defined based on precise statistic information of 1199 tungsten mining areas and thorough the summary of metallogenic regularities. Based on studies of the metallogenic regularity of tungsten deposits, skarn type (or greisen type), quartz vein type and massif-type of tungsten deposits are thought to be the key prediction types. 65 tungsten-forming belts and 22 key ore concentration areas were ascertained and a distribution map of tungsten-forming belts of China was compiled, which provided a theoretical basis for evaluation and prediction of potential tungsten resources. 相似文献
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ZHANG Changqing LIU Huan WANG Denghong CHEN Yuchuan RUI Zongyao LOU Debo WU Yue JIA Fudong CHEN Zhenghui MENG Xuyang 《《地质学报》英文版》2015,89(4):1333-1358
Lead and zinc resources are abundant in China, with the reserves of 100 million tons ranking only second in the world. There are more than 3000 lead-zinc mine areas nationwide. The classification of lead-zinc (Pb-Zn) deposits has been a highly controversial issue. From the standpoint of evaluating the potential of mineral resources, we construct a Pb-Zn deposit predictive type of classification scheme, and propose a Pb-Zn deposit comprehensive classification scheme (including 5 classes and 13 sub-types) that regards mineralization as the primary factor and the ore rock as secondary. According to the temporal and spatial distribution of Pb-Zn deposits, we conclude that a multi-period, multi-cycle orogenic environment is the most favorable for lead-zinc deposit growth, that the Proterozoic is the major eon for the growth of igneous-type deposits, the Paleozoic is an important development era for sedimentary Pb-Zn deposits, and the Mesozoic and Cenozoic are the heyday eras of magmatic type lead-zinc deposits. On this basis, we analyse the relationship between tectonic evolution and Pb-Zn metallogenic, and propose that the key factors determining geological mineralization are the metallogenic epoch of mineralization and tectonic environment, which determine the temporal and spatial distribution. 相似文献