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1.
浅成低温热液金矿研究现状及其趋势 总被引：8，自引：0，他引：8
浅成低温热液金矿指产于陆相火山岩系中或相邻岩石中，形成温度低于３００℃，成矿流体是大气降水与岩浆热液形成的混合热液的一类金矿床。近几年对浅成低温热液金矿研究结果突破了浅成低温热液金矿只形成于中一新生代火山岩系中的概念，在石炭纪陆相火山岩中发现了浅成低温热液金矿。浅成低温热液矿床一般产于岛弧环境或大陆边缘环境中一酸性陆相火山夺系及相邻岩石中。根据矿物组合及蚀变特征，浅成低温热液矿床可分为高硫型、低硫 相似文献
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河南祁雨沟热液角砾岩体型矿床成硫流体研究 总被引：46，自引：12，他引：34
祁雨沟金矿床产于燕山期热液角砾岩筒内,通过对４号角砾岩体胶结物和石英－碳酸盐胶内流体包裹体研究表明,其中的包裹体类型非常复杂,有气体包裹体,气液包裹体,液体所裹体,含子矿物高盐裹体和含ＣＯ２包裹体五种类型,成矿的初始热液为高温高盐流体,它们来源于燕山期花岗岩浆热液,由于角砾岩体的隐爆,流体减压沸腾及古大气水的混入,热液中的金被沉淀成矿,形成胶结物型和脉型金矿化,金矿的开始成矿于温度较高（３１０～３ 相似文献
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新疆萨瓦亚尔顿金矿流体包裹体成分、矿床成因和成矿预测 总被引：4，自引：6，他引：4
新疆萨瓦亚尔顿金矿区发育含矿和无矿石英脉,无矿石英、含矿石英及主要载金矿物黄铁矿所含包裹体捕获的流体成分有明显差异,分别代表了成矿前、成矿早阶段和主成矿阶段的流体特征。早阶段成矿物质沉淀的主要机制为流体不混溶作用,形成含矿石英、含钠矿物和部分黄铁矿等;主成矿阶段则以流体浓缩及流体混合为主要机制,形成大量黄铁矿等载金矿物。萨瓦亚尔顿金矿的成矿流体成分特征与世界造山型的中温热液脉状金矿类似,尤其是与乌兹别克南天山造山带的穆龙套金矿类似,表明其为较典型的穆龙套式的造山型金矿床。Ⅺ、Ⅱ矿化带流体成分特征与矿化最好的Ⅳ带类似,勘探前景较好;相反,Ⅰ矿化带与Ⅳ带差异明显,不宜作为勘探重点。 相似文献
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新疆伊犁盆地砂岩型铀矿床层间氧化带中粘土矿物特征及与铀矿化关系研究 总被引：2，自引：0，他引：2
新疆伊犁盆地砂岩型铀矿床,由于规模大、成矿环境和成矿条件好,在同类型矿床中具有良好的代表性,研究矿床的成矿作用对今后找矿勘查以及开采具有重要理论意义。本文在区域赋铀层位沉积环境研究基础上,以赋矿围岩为研究主体,对伊犁盆地典型铀矿床沉积序列和矿床的控矿层位开展研究,通过对赋矿沉积层位中粘土质对铀矿成矿的控制作用及与铀矿的空间联系和成因分析,开展系统的铀矿床学、能谱测试、显微结构、扫描电镜、地球化学、氢氧同位素等研究,特别是开展了富矿砂体中粘土矿物的种类、成分、结构、同位素、成因等的研究,对粘土质矿物对铀矿成矿的控制作用进行了系统研究。通过研究粘土矿物在伊犁盆地蒙其古尔砂岩型铀矿床成矿过程中的作用及与铀矿的空间联系和成因分析表明:粘土矿物在层间氧化带中分布较为广泛,在主要矿体的氧化还原过渡带中,尤其是部分具有强烈粘土蚀变的砂岩层中铀含量较其他层位要高,反映出粘土矿物与铀成矿是有成因关联的。通过系统的扫描电镜、能谱测试研究,从微观证明粘土矿物与铀成矿有相关关系;粘土矿物的存在导致在近地表含氧含铀水在经过砂岩孔隙时被具有较强吸附能力和巨大表面自由能的粘土矿物所吸附,形成了铀含量较高的片状,团块状的粘土矿物,其在铀成矿作用中起到了吸附和界面的作用,有利于赋矿空间的形成及定位。结合沉积作用、构造活动和后期流体成矿作用等因素,分析了成矿机制和成矿作用,赋矿层位中的粘土矿物、其它成矿条件如岩性(赋矿层和矿源层)、构造(对铀矿化的动力和对地下水径流及铀矿体)等共同控制了铀成矿作用。 相似文献
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碳酸岩型稀土矿床是全球稀土最主要的来源。磷酸盐是该成矿体系中常见的组分,但对其在碳酸岩稀土成矿过程中的具体作用仍缺少系统的认识。笔者等综述了磷酸盐在碳酸岩岩浆形成、演化和稀土富集成矿过程中作用,并提出现存问题和研究展望。磷在碳酸盐熔体中具有很高的溶解度。磷的存在有利于稀土在地幔极低程度部分熔融过程和碳酸盐—硅酸盐液态不混溶过程中优先进入碳酸盐熔体,形成初始碳酸盐熔体中稀土的预富集。碳酸岩岩浆演化过程中,稀土将优先进入到不混溶的磷酸盐熔体或独居石和磷灰石等磷酸盐矿物中,这些熔体和矿物的行为很可能是控制体系中稀土行为和成矿潜力的关键因素。岩浆作用过程中形成的富稀土磷酸盐矿物还可为热液阶段稀土矿化提供成矿物质来源。磷酸盐还是热液过程中稀土的有效沉淀剂,有利于轻重稀土矿物在流体晚期阶段成矿。未来工作应更多关注磷酸盐在碳酸岩岩浆演化过程中的作用及其中重稀土的富集机理研究,针对具体成岩成矿过程开展实验岩石学和熔体包裹体研究。 相似文献
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宝国老金矿产于辽西太古宙高变质绿岩带,受近东西向韧性剪切带控制,多金属硫化物石英脉型,银金矿为主要含金矿物,矿石品位高。成矿经历火山－沉积作用、区域变质作用和动力变质三个阶段,成矿时间中含古元古代的信息,成矿流体可能为变质热液混合岩浆热液,成矿温度在１６０～３１０℃之间。 相似文献
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Industrial uranium orebodies have recently been found through in-depth uranium exploration in the Luohe Formation in the southwestern Ordos Basin, which is an important breakthrough in deep prospecting for sandstone-type uranium deposits. The composition, content and characteristics of clay minerals in the Luohe Formation in the Zhenyuan area were systematically studied by means of thin section identification, scanning electron microscopy, X-ray diffraction and altered mineral spectral scanning. Unlike the most important uranium-bearing rock series in the Zhiluo Formation in the northeast and southwest of the basin, the ore-bearing Luohe Formation sandstone has low contents of clay minerals while the clay mineral assemblages vary in different sand bodies. Among them, the main types of mudstone, oxidized sandstone, calcareous sandstone and mineralized sandstone are illite-smectite mixed-layer mineral and illite, followed by kaolinite and chlorite, the main types uranium-rich sandstone and gray-green sandstone are kaolinite and illite-smectite mixed-layer mineral, followed by illite and chlorite. Even though adsorption of clay minerals, such as chlorite, illite-smectite mixed-layer mineral, kaolinite, and illite may contribute to U enrichment and uranium mineral precipitation, no correlation between clays and uranium minerals have been observed, indicating that clay minerals are not the main factor affecting uranium enrichment during the deep metallogenic process. The study of clay minerals in the Luohe Formation sandstone demonstrated that there are at least two phases of chlorite and one phase of kaolinite in the study area, which respectively represent two phases of alkaline fluid and one phase of acid fluid activities, revealing a fluid phase transition of alkaline-acidic-alkaline. Therefore, the clay minerals can be used as an important indicator for uranium mineralization. © 2020, Science Press. All right reserved. 相似文献
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Youko Miyoshi Jun‐ichiro Ishibashi Kazuhiko Shimada Hiroyasu Inoue Seiichiro Uehara Katsuhiro Tsukimura 《Resource Geology》2015,65(4):346-360
Iheya‐North‐Knoll is one of the small knolls covered with thick sediments in the Okinawa Trough back‐arc basin. At the east slope of Iheya‐North‐Knoll, nine hydrothermal vents with sulfide mounds are present. The Integrated Ocean Drilling Program (IODP) Expedition 331 studied Iheya‐North‐Knoll in September 2010. The expedition provided us with the opportunity to study clay minerals in deep sediments in Iheya‐North‐Knoll. To reveal characteristics of clay minerals in the deep sediments, samples from the drilling cores at three sites close to the most active hydrothermal vent were analyzed by X‐ray diffraction, scanning electron microscope and transmission electron microscope. The sediments are classified into Layer 0 (shallow), Layer 1 (deep), Layer 2 (deeper) and Layer 3 (deepest) on the basis of the assemblage of clay minerals. Layer 0 contains no clay minerals. Layer 1 contains smectite, kaolinite and illite/smectite mixed‐layer mineral. Layer 2 contains chlorite, corrensite and chlorite/smectite mixed‐layer mineral. Layer 3 is grouped into three sub‐layers, 3A, 3B and 3C; Sub‐layer 3A contains chlorite and illite/smectite mixed‐layer mineral, sub‐layer 3B contains chlorite/smectite and illite/smectite mixed‐layer minerals, and sub‐layer 3C contains chlorite and illite. Large amounts of di‐octahedral clay minerals such as smectite, kaolinite, illite and illite/smectite mixed‐layer mineral are found in Iheya‐North‐Knoll, which is rarely observed in hydrothermal fields in mid‐ocean ridges. Tri‐octahedral clay minerals such as chlorite, corrensite and chlorite/smectite mixed‐layer mineral in Iheya‐North‐Knoll have low Fe/(Fe + Mg) ratios compared with those in mid‐ocean ridges. In conclusion, the characteristics of clay minerals in Iheya‐North‐Knoll differ from those in mid‐ocean ridges; di‐octahedral clay minerals and Fe‐poor tri‐octahedral clay minerals occur in Iheya‐North‐Knoll but not in mid‐ocean ridges. 相似文献
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Ezz El Din Abdel Hakim Khalaf 《Arabian Journal of Geosciences》2014,7(7):2603-2624
Wadi Queih basin hosts a ～2,500-m thick Neoproterozoic volcanoclastic successions that unconformably lie over the oldest Precambrian basement. These successions were deposited in alluvial fan, fluviatile, lacustrine, and aeolian depositional environments. Diagenetic minerals from these volcaniclastic successions were studied by X-ray diffractometry, scanning electron microscopy, and analytical electron microscopy. The diagenetic processes recognized include mechanical compaction, cementation, and dissolution. Based on the framework grain–cement relationships, precipitation of the early calcite cement was either accompanied or followed by the development of part of the pore-lining and pore-filling clay cements. Secondary porosity development occurred due to partial to complete dissolution of early calcite cement and feldspar grains. In addition to calcite, several different clay minerals including kaolinite, illite, and chlorite with minor smectite occur as pore-filling and pore-lining cements. Chlorite coating grains helps to retain primary porosity by retarding the envelopment of quartz overgrowths. Clay minerals and their diagenetic assemblages has been distinguished between primary volcaniclastics directly produced by pyroclastic eruptions and epiclastic volcaniclastics derived from erosion of the pre-existing volcanic rocks. Phyllosilicates of the epiclastic rocks display wider compositional variations owing to wide variations in the mineralogical and chemical compositions of the parent material. Most of the phyllosilicates (kaolinite, illite, chlorite, mica, and smectite) are inherited minerals derived from the erosion of the volcanic basement complex, which had undergone hydrothermal alteration. Smectites of the epiclastic rocks are beidellite–montmorillonite derived from the altered volcanic materials of the sedimentary environment. Conversely, phyllosilicate minerals of the pyroclastic rocks are dominated by kaolinite, illite, and mica, which were formed by pedogenetic processes through the hydrothermal influence. 相似文献
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应用X射线衍射(XRD)对南海北部陆架海域225个站位表层沉积物黏土组分进行分析,结果表明,研究区黏土矿物总体以伊利石和绿泥石为主,高岭石和蒙脱石质量分数少,绿泥石、高岭石与蒙脱石质量分数呈明显的负相关关系。根据南海北部陆架海域表层沉积物中黏土矿物空间分布特征,结合邻近河流的黏土矿物组分以及洋流搬运作用,雷州半岛东部海域伊利石主要来源于广东沿海河流和珠江,绿泥石来自台湾岛,蒙脱石主要由吕宋河流提供,高岭石则由广东沿海河流和海南岛入海河流提供;雷州半岛西部海域伊利石来源于珠江,绿泥石和高岭石由红河提供,蒙脱石可能受广西入海河流携带的沉积物影响。 相似文献
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X. L. Sun X. G. Zhang J. L. Lin Z. X. Zhao D. W. Huang 《Australian Journal of Earth Sciences》2013,60(8):1163-1174
AbstractThe characteristics and distribution of clay minerals and their effects on reservoir quality in the Huagang sandstones in the Xihu Sag, East China Sea Basin were studied by using X-ray diffraction, casting thin-sections, scanning electron microscopy, electron microprobe analysis, fluid inclusion analysis, constant-rate mercury injection and nuclear magnetic resonance. Clay minerals consist of kaolinite, chlorite, illite and illite–smectite mixed layer (I/S); kaolinite forms from dissolved feldspars, chlorite occurs as clay coatings that are transformed from clay precursors owing to the flocculation of suspended detrital clays or the crystallisation of pore fluids, and illite forms from the illitisation of detrital smectite, authigenic kaolinite and K-feldspars. Clay distribution is controlled by sedimentary environments, burial history and lithologies. Typical reservoirs in the western sub-sag are thin and developed in braided river facies at relatively shallow burial depths with clays dominated by kaolinite. However, typical reservoirs in the central inversion tectonic zone are thicker and developed in a braided delta front facies at deeper burial depths with clays mainly consisting of chlorite, illite and I/S. High-quality reservoirs are characterised by coarse granularity, high quartz content and low clay content with widespread development of chlorite coatings that inhibit quartz cements at low temperatures. At higher temperatures, the high-quality reservoirs develop more pores providing growth space for quartz cements and result in the coexistence of chlorite coatings and quartz cements. The high-quality reservoirs are controlled by their lithological characteristics rather than chlorite coatings. Illite and I/S clays create severe damage to reservoirs by reducing the size and connectivity of pore-throats. 相似文献
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The results of the study of clay mineral alterations in Upper Pleistocene sediments of the southern trough in the Guaymas Basin (Gulf of California) due to the influence of hydrothermal solutions and heat produced by sill intrusions are discussed. Core samples from DSDP Holes 477 and 477A were taken for the analysis of clay minerals. Application of the method of modeling X-ray diffraction patterns of oriented specimens of the finely dispersed particles made it possible to establish the phase composition of clay minerals, determine their structural parameters, and obtain reliable quantitative estimates of their contents in natural mixtures. The modeling data allowed us to characterize reliably the transformation of clay minerals in sediments of the hydrothermally active southern trough in the Guaymas Basin. In Upper Pleistocene sandy–clayey sediments of the southern trough, changes in the composition of clay minerals occurred under the influence of a long-living hydrothermal system. Its lower part (interval 170.0–257.5 m) with maximum temperatures (~300°C) was marked by the formation of chlorite. Terrigenous clay minerals are not preserved here. Saponite appears at a depth of 248 m in the chlorite formation zone. Higher in the sedimentary section, the interval 146–170 m is also barren of terrigenous clay minerals. Sediments of this interval yielded two newly formed clay minerals (chlorite and illite), which were formed at lower temperatures (above 180°C and below 300°C, approximately up to ~250°C), while the relatively low-temperature upper part (110–146 m) of the hydrothermal system (from ~140°C to ~180°C) includes the mixture of terrigenous and newly formed clay minerals. Terrigenous illite is preserved here. Illitization of the mixed-layer illite–smectite was subjected to illitization. The terrigenous montmorillonite disappeared, and chlorite–smectite with 5–10% of smectite layers were formed. In the upper interval (down to approximately 110 mbsf), the composition of terrigenous clay minerals remains unchanged. They are composed of the predominant mixed-layer illite–smectite and montmorillonite, the subordinate illite, mixed-layer chlorite–smectite with 5% of smectite layers, mixed-layer kaolinite–smectite with 30% of smectite layers, and kaolinite. This composition of clay minerals changed under the influence of sill intrusions into the sedimentary cover at 58–105 m in the section of Hole 477. The most significant changes are noted in the 8-m-thick member above the sill at 50–58 m. The upper part of this interval is barren of the terrigenous mixed-layer illite–smectite, which is replaced by the newly formed trioctahedral smectite (saponite). At the same time, the terrigenous dioctahedral smectite (montmorillonite) is preserved. The composition of terrigenous clay minerals remains unchanged at the top of the unit underlying the sill base. 相似文献
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The clay mineralogy of the Scottish Dalradian meta-limestones has been studied mainly by X-ray diffraction. In the samples from the north-east part of the Dalradian outcrop, which often show evidence of intense metamorphism, clay minerals found include saponite, regularly and irregularly interstratified smectite-chlorite, swelling chlorite, normal chlorite, illite and kaolinite. Limestones from the weakly metamorphosed South-West Highlands area contain only kaolinite, illite and chlorite. The genesis of the clay minerals is considered, particular attention being paid to the swelling minerals from the north-east region. 相似文献
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通过X射线衍射系统分析了杭州湾地区SE2孔全新世沉积物的黏土矿物组成,结果显示研究层段黏土矿物主要由伊利石、绿泥石、高岭石和蒙脱石组成;伊利石结晶度较好,化学风化指数普遍大于0.5,表明以化学风化为主,且风化趋势自下而上呈递减趋势。通过对比中国东南部主要河流沉积物的黏土矿物组成,认为钱塘江下切河谷全新世沉积物的黏土矿物组成具有较好的物源指示意义: 全新世 Ⅰ 段(即古河口湾和河漫滩)沉积物主要来自钱塘江上游,特征黏土矿物为高岭石,河口外物质贡献不大;Ⅱ 段(即现代河口湾和近岸浅海)沉积物包含较多蒙脱石,表明不仅包括钱塘江上游物质,河口外长江物质也开始进入钱塘江河口。黏土矿物中,高岭石对气候有较好的指示作用:中全新世高岭石含量达到最高值,反映气候最为湿热,化学风化程度最高;晚全新世含量逐渐降低,反映气候逐渐回冷,化学风化强度降低。 相似文献
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通过X射线衍射系统分析了杭州湾地区SE2孔全新世沉积物的黏土矿物组成,结果显示研究层段黏土矿物主要由伊利石、绿泥石、高岭石和蒙脱石组成;伊利石结晶度较好,化学风化指数普遍大于0.5,表明以化学风化为主,且风化趋势自下而上呈递减趋势。通过对比中国东南部主要河流沉积物的黏土矿物组成,认为钱塘江下切河谷全新世沉积物的黏土矿物组成具有较好的物源指示意义: 全新世 Ⅰ 段(即古河口湾和河漫滩)沉积物主要来自钱塘江上游,特征黏土矿物为高岭石,河口外物质贡献不大;Ⅱ 段(即现代河口湾和近岸浅海)沉积物包含较多蒙脱石,表明不仅包括钱塘江上游物质,河口外长江物质也开始进入钱塘江河口。黏土矿物中,高岭石对气候有较好的指示作用:中全新世高岭石含量达到最高值,反映气候最为湿热,化学风化程度最高;晚全新世含量逐渐降低,反映气候逐渐回冷,化学风化强度降低。 相似文献
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We analyzed the clay mineral assemblages, content and mineralogical characteristics of Hole U1438A sediment recovered from Amami Sankaku Basin during International Ocean Discovery Program (IODP) expedition 351. The results show that the clay minerals are mainly composed of illite (average 57%), smectite (average 26%), chlorite (average 14%) and minor kaolinite(average 3%). The crystallinity of illite in all samples are good (<0.4 Δ° 2θ), and the chemical indexes of illite in all samples are low (<0.4). Both indicate that illite in Hole U1438A formed in cold and dry climate. By comparing clay mineral assemblages of hole U1438A and the potential sediment sources, we suggest that smectite be mainly derived from the volcanic materials around Amami Sankaku Basin. Illite, chlorite and kaolinite are mainly derived from the Asian dust. The ratios of (illite+chlorite)/smectite show a phased increase over the last 350 ka, which is consistent with the cold and drying trend of the Asian continent since late Pleistocene. The high ratios of (illite+chlorite)/smectite and (illite+chlorite)/kaolinite during glacial period indicate that much more Asian dust was input into the Amami Sankaku Basin, which are responded to the aridity of Asian continent and strengthened east Asian Monsoon during glacial period. 相似文献