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溆浦砂锡矿床床赋存在第四系冲积层中、锡石主要富集在度部砂砾石层。矿体呈层状，平均厚０．９２－１．６６ｍ，锡石平均品位６３２－１２２９ｇ／ｍ＾３。伴生锆石、独居石。本砂锡矿床与白马山风岗岩风化壳密切有关。矿床成因属第四系全新统冲积－堆积型细谷砂矿。 相似文献
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临武铁砂坪锡石-硫化物矿床位于香花岭多金属矿田内，属断裂充填交代型脉状锡矿床。矿区有锡石-硫化物和锡石-石英脉两种类型锡矿脉，严格受中泥盆统跳马涧组碎屑岩和棋子桥组灰岩中的NE、NW向断裂控制，IV号锡石-硫化物矿脉带长约2500m，宽500m，平均品位Sn0．36％，最高品位Snl．36％。矿脉产状与容矿断裂产状一致，赋存于棋子桥组的矿体为特殊的深浅相间的条纹岩，它是一种特殊的锡矿工业类型，在湘南地区具有找锡指导意义． 相似文献
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作者通过对曾家垅含锡矿物特征及赋存状态的分析认为，曾家垅含锡独立矿物以锡石为主，次为马来亚石及黄锡矿。在华南锡成矿带中，马来亚石的矿物组合在曾家垅锡矿床中首次发现，读矿物组合在岩浆期后不同的成矿阶段各具特色。矽卡岩晚期高温氧化物阶段和石英硫化物阶段早期是锡石、马来亚石的主要成矿期，所晶出的大量锡石构成了曾家垅锡矿床的主体。 相似文献
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临武铁砂坪锡石—硫化物矿床位于香花岭多金属矿田内，属断裂充填交代型脉状锡矿床。矿区有锡石—硫化物和锡石—石英脉两种类型锡矿脉，严格受中泥盆统跳马涧组碎屑岩和棋子桥组灰岩中的NE、NW向断裂控制，Ⅳ号锡石—硫化物矿脉带长约2 500 m，宽500 m，平均品位Sn 0.36 %，最高品位Sn 1.36 %。矿脉产状与容矿断裂产状一致，赋存于棋子桥组的矿体为特殊的深浅相间的条纹岩，它是一种特殊的锡矿工业类型，在湘南地区具有找锡指导意义。 相似文献
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来利山锡矿床与小龙河锡矿床是滇西地区典型的云英岩型锡矿床。为揭示它们在成因上深层次的差异性,对来利山锡矿和小龙河锡矿的锡石进行了电子探针成分分析、镜下观察以及成矿环境对比分析。结果表明,锡石中的铁多以Fe~(3+)的形式与Sn~(4+)发生类质同象,氧逸度越高,锡石中Fe~(3+)越多,宏观上表现为锡石的颜色越深。来利山矿区锡石中Fe含量明显低于小龙河矿区,且锡石颜色明显比小龙河矿区颜色浅,反映了来利山锡矿成矿环境相对开放,成矿流体氧逸度偏低,流体中Sn络合物迁移能力较强,在花岗岩体外接触带的围岩裂隙中形成外云英岩型锡矿床;而小龙河锡矿成矿环境相对封闭,成矿流体氧逸度偏高,流体中Sn络合物迁移能力较弱,多在花岗岩体顶部的构造裂隙中形成内云英岩型锡矿床。 相似文献
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铁嶂锡矿床赋矿围岩为下侏罗统金鸡组下部的砂页岩,其锡含量较高,为矿源层。矿体分布于北东向和北西向断裂构造中,可分为大脉型与细脉带型矿体。锡石有两类:一类为沉积的胶状锡石和由胶体变晶生成的微晶锡石,分布于富动植物化石和碳质的千枚状页岩和富锡的砂岩结核中;第二类为粒状锡石,与石英、硫化物一起呈脉状产出。矿床系沉积变质热液改造成因。 相似文献
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本文通过对江西省南城县岳口砂金矿中的砂金进行电子探针,分析了自然金的形态、粒度及矿物组合,阐明了砂金矿的成因,并探讨了砂金与原生金矿关系,提出了原生金矿的类型,指出了震旦系变质岩区为金成矿远景区。 相似文献
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论贵州中部九架炉组铝矿系冲洪积扇沉积特征 总被引：1，自引：0，他引：1
通过对贵州中部石炭系九架炉组铝矿系的较系统研究,认为该套沉积物是由冲洪积作用及湖泊作用在负地形堆积而成的陆相岩系,冲洪积扇是最常见的一种冲洪积相沉积物,贵州中部大部分大型铝土矿床都是由此种沉积作用形成的扇群席状砂体经铝土矿化改造而成。 相似文献
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秦岭地区砂金分布特征与成矿机理 总被引：1，自引：0，他引：1
秦岭地区砂金矿床大部分分布在嘉陵江、汉水及其它们的支流流域。总结了砂金矿床分布特征,并将３种类型进行了对比。系统地对矿源、搬运、储存和富集的成矿模式、成因机理进行了研究。地貌与产构造运动在成矿中占有重要地位。 相似文献
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塞拉利昂中部马卡利地区出露有大片的太古界花岗-绿岩带地质体,其金矿资源丰富。通过矿产勘查和成矿规律研究表明,金的来源与太古界花岗-绿岩带地体密切相关。岩金矿床类型为含铁建造金矿床,主要赋存于绿岩带的绿片岩中及含铁建造的片岩中,受褶皱和断裂构造控制;砂金矿的类型为河流冲积型砂金矿,主要分布在花岗-绿岩带内及其周边河流中的全新统冲积层中下部砂砾石层中。重砂异常和地球化学异常区内具备良好的岩金、砂金成矿地质背景和找矿前景,实施砂金-岩金综合找矿方法,找矿潜力巨大。 相似文献
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华亭矿区延安组形成于河流、湖泊三角洲-湖泊沉积体系,其中以湖泊三角洲平原占优势,其沉积相有河流相、冲积扇相、湖泊三角洲相、湖泊相.煤系沉积初期,以河流及冲积扇沉积为主,沉积中期则以湖泊三角洲沉积为主,晚期以湖泊环境为主,延安组各煤层大多是在湖泊三角洲平原上泥沼化形成的. 相似文献
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An elegantly simple, aqua regia-based, ICP-MS analytical procedure is used to compare the trace element composition of density-separated alluvial native Au from seven stream silt samples with three samples of geographically-associated Au from a prospective ore deposit in central British Columbia. Not all of the alluvial Au could have come from the ore deposit based on present drainage. The silt sample Au, averaging four alluvial grains and totaling 12–250 μg per sample, generally yielded measurable concentrations for V, Fe, Cu, As, Pd, Ag, Sb, Pt and Bi. The bedrock Au samples represent the three dominant rock types in the showing. Their Au trace element compositions largely bracket the alluvial Au. Multidimensional scaling (exploratory statistics) shows that trace elements in the native Au form lithophile, chalcophile and siderophile groupings. This indicates that a small set of geochemical processes formed all the Au in one geologic environment. Previous work shows that Au from individual deposits has distinct assemblages of detectable elements. Given these observations and that detectable elements are the same in both the deposit and alluvial Au, and that concentrations in the former bracket those of the latter, it is concluded that the source of the alluvial Au has probably been identified. Apparently neither mineral inclusions nor weathering impaired fingerprinting of the Au. The simplicity of the approach indicates that this is a useful exploration tool for determining the bedrock source of alluvial Au. The study also shows that silt sample exploration in glaciated terrains must recognize that paleo-ice movement and paleo-stream directions can yield geographic distributions of alluvial Au that cannot be explained by present-day drainage patterns. Thus this simple analytical/exploration technique is potentially very useful to the exploration industry. 相似文献
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The Vagran placer cluster is located on the eastern slope of Northern Urals. During > 100 years of gold mining history approximately 40 tons of gold have been extracted from the placer deposits.Bedrocks of the region consist of high metamorphic Upper Proterozoic and Paleozoic terrigeneous, terrigeneous-volcanogenic and igneous rocks. Gold placer deposits are mostly alluvial genesis deposits and of Quaternary to Oligocene (?) age. The alluvial deposits consist of gravel with pebbles, boulders, and sandy clay covered by sandy silt and a soil layer. The thickness of the alluvial sequence is usually 5–10 m and reaches 18 m in the main watercourses of the third order. Nearly all of the alluvial sediments are gold bearing but concentrations of economic importance prevail in the bottom part of the sequence above the bedrock.There are four different types of gold particles: (I) rounded and well-rounded particles of high fineness and homogeneous inner structure, (II) rounded to sub-rounded high fineness particles with a pure gold rim developed over a core, (III) crystallomorphic (idiomorphic) high fineness with a homogeneous inner structure, and (IV) irregular angular and subangular particles of medium fineness with a significant content of Ag (10–40 wt.%) and elevated Hg (up to 1.15 wt.%).The first type is prevalent and comprises up to 65% of the total gold particles; it is uniformly distributed throughout the territory. There are features with initially complicated dendritic and laminar shaped particles which were rounded during transportation. The second and third types have a propensity for zones of the inherited erosion–tectonic depressions. Apparently, types I, II and III are related with orogenic mesothermal gold-sulfide-quartz mineralization; the differences of these types depend on the primary zonation of ore bodies and supergenic transformation of the alloys. They were connected with middle-depth ore bodies of an orogenic gold-sulfide-quartz formation. The fourth type is evident of nearby transportation from primary sources and a short duration of supergenic influence. It is controlled by a zone of NW-SE orientation, diagonal to the main structures of Ural Fold Belt.The plot of Au content vs coefficient of heterogeneity (ratio of the Au content in the core and in the rim of the grains) is the distinguishing factor between the four types of gold grains both by primary hypogenetic characteristics and supergenetic features.No corresponding lode occurrence of gold-sulfide-quartz mineralization has been identified to date in this region. Placer gold concentrations are related to the intermediate hosts of the Mesozoic-Cenozoic surfaces of the Ural peneplain uplift in the Oligocene and eroded in Miocene-Quaternary time. This factor determines the widespread distribution of placer gold in the territory of the Vagran cluster.The large, Carlin-type Vorontsovsk gold deposit is located 60 km south-east from the Vagran area. It has a shallow erosional level, small size of native gold, and its distal location from the placer deposits makes it an unlikely primary source for the Vagran placers. However, mineralization of this type of deposit is noted within the cluster.Gold of the fourth type nearly resembles the gold of the Vorontsovsk deposit and, apparently, the source is related to the same hydrothermal mineralization event. ICP MS analyses of the quartz-sulfide lodes in the floor of gold-bearing valleys revealed a gold content of 2.0–6.9 g/t in the zone of type IV distribution. Therefore, gold of the fourth type can be used as an indicator for the exploration of primary bedrock mineralization. The geological setting and typomorphic features of this placer gold shows that the primary gold mineralization is similar to the Vorontsovsk deposit and within the zone of distribution of the placer gold of the fourth type. 相似文献
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库车坳陷古近系库姆格列木组是盆地内重要的含油气层段。本文应用高精度层序地层学的理论和方法，在库车坳陷古近系库姆格列木组地层中划分出3个三级层序、14个四级层序和数十个五级层序(准层序)。四级层序中发育有冲积扇、辫状河、曲流河、辫状河三角洲和滨浅湖等沉积体系，局部地区发育下切水道、干旱盐湖、泻湖—海湾、半深湖、浊流—重力流等沉积。该组下部四级层序：Psk1、Psk5和中上部四级层序Psk7、Psk12等的砂质沉积形成区内的主力储层，主要分布在盆地北—西北缘和东—东南缘，与其上覆的泥岩、膏泥岩形成有利的储盖组合。 相似文献
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Darío Andrés Giagante Salvador Aliotta Silvia Susana Ginsberg Laura Gabriela Vecchi Jorge Osvaldo Spagnuolo 《Quaternary Research》2011,75(3):614-623
The purpose of this research is to analyze the seismostratigraphic and paleoenvironmental features of an ancient fluvial deposit characterized by the presence of paleochannels and sedimentary structures in Bahía Blanca estuary, Argentina. To this end, high-resolution seismic methods were used. Paleochannels exhibiting v-shaped cuts were found at different topographic positions at the base of this deposit. It was observed that channel silting is indicative of the relative change of river base level and the consequent migration of fluvial tributaries. This alluvial deposit is composed of low compacted fine sand and its middle–upper facies is characterized by the presence of horizontal and discontinuous wavy reflectors. The upper boundary of this deposit is an erosive discontinuity resulting from Holocene sea-level rise during which the mouth of old fluvial courses underwent changes. The deposit was subsequently buried by sandy and clayey silt sediments. The paleodrainage at subbottom indicates that this deposit is associated with an ancient river mouth. Based on the seismostratigraphic and lithological characteristics and the paleochannel structures found in the study area, it can be concluded that the deposit analyzed is an alluvial sequence formed in the period from the Middle-Late Pleistocene to Holocene marine transgression. 相似文献