共查询到20条相似文献，搜索用时 31 毫秒
1.
辽宁五龙金矿铋矿物与金矿化关系研究 总被引：6，自引：0，他引：6
辽宁五龙金矿的铋矿物为辉铋矿，自然铋和辉铅铋矿，它们与金矿化关系非常密切，在高温条件下，Ｂｉ与Ａｕ呈固溶体形式或某种化合物形式存在，随着温度的下降，Ｂｉ与Ａｕ分离构成两种独立矿物，二者紧密共生，在含金石英矿体中，铋矿物的多少直接影响矿石品位，铋矿物是重要的金矿化指示矿物。 相似文献
2.
国内难溶性钾矿资源及其开发利用 总被引：2，自引：0，他引：2
国内难溶性钾矿资源较丰富,可分为含钾岩石和含钾矿物两大类及若干亚类。含钾沉积岩有:富钾火山沉积凝灰岩(绿豆岩),含钾砂、页岩,含钾泥灰岩,含钾石膏泥,含钾磷块岩等;含钾岩浆岩有:霞石正长岩、霓辉石石英正长岩、流纹斑岩、正长斑岩、花岗伟晶岩、钾长粗面凝灰熔岩等;含钾变质岩有:钾长浅粒岩、云母片岩、钾长混合片麻岩等;可作钾矿资源的含钾矿物有:钾长石、明矾石、伊利石、白榴石、海绿石等。目前,绿豆岩,含钾砂、页岩,流纹岩,海绿石,白榴石等已可单独开采利用,制作钾肥;霞石正长岩、伊利石、钾长石、明矾石等可被综合回收利用;粗面岩、响岩、粗玄岩,含钾泥灰岩、钾长浅粒岩等尚待开发利用。 相似文献
3.
Crystallization conditions of the Wiborg rapakivi batholith, SE Finland: an evaluation of amphibole and biotite mineral chemistry 总被引：5，自引：0，他引：5
B. A. Elliott 《Mineralogy and Petrology》2001,72(4):305-324
Summary The wiborgite and dark wiborgite rapakivi granite phases of the Wiborg batholith in southeastern Finland compose about 80%
of the total batholith area. A new study of the dominant mafic silicate minerals, in comparison with mafic silicates from
more evolved granite phases, hybridized granite and mafic magmatic enclaves provide insights into the overall petrogenesis
of the Wiborg batholith. All of the mafic silicate minerals are iron-rich, reflective of the whole rock compositions. Biotite
is annitic, calcic amphibole is ferro-edenite to hastingsite, and subsolidus Fe-Mg amphibole is found as accessory grunerite.
Temperatures derived from amphibole-plagioclase thermometry suggest crystallization at about ∼ 740 °C. Pressure estimates
derived from Al in amphibole barometry range between 2.5 and 5.4 kilobars. This is noticeably higher than the previous estimates
of 1 kbar for the Wiborg batholith. Oxygen fugacity estimates from biotite suggest low fO2 initial values and increase from FMQ to above NNO for late stage granite phases.
Received February 29, 2000; revised version accepted December 27, 2000 相似文献
4.
物源分析是古地理重建与盆地分析的关键,典型的物源区包括岩浆弧、大陆地块、再旋回造山带等。重矿物种类多样,蕴含丰富的母岩信息,是物源分析的重要对象。现代砂的研究表明,不同大地构造背景下形成的沉积物具有不同的重矿物组合。遗憾的是,由于古代沉积的重矿物组合在成岩过程中会被改造,现代砂的重矿物组合与物源区的耦合规律并不能直接应用于古代砂岩。科学界尚不清楚岩浆弧与大陆地块来源的古代砂岩的重矿物特征。西藏日喀则弧前盆地与特提斯喜马拉雅侏罗纪—古近纪砂岩物源明确,要么来自亚洲大陆的冈底斯弧,要么来自印度大陆地块,是探讨岩浆弧与大陆地块来源的古代砂岩重矿物特征的绝佳场所。16件砂岩重矿物定量分析结果表明,两个物源区来源的砂岩重矿物组合均被成岩作用严重改造,辉石、角闪石等不稳定矿物消失,绿帘石等自生矿物出现;冈底斯弧来源的砂岩以出现大量绿帘石或磷灰石为特征,ZTR指数小于40;印度大陆地块来源的砂岩以出现大量锆石、电气石和金红石为特征,ZTR指数大于75。这一结果指示岩浆弧与大陆地块来源的砂岩的重矿物组合具有明显差异性,可以用来探讨物源的大地构造背景。 相似文献
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Kentaro Nakamura 《Geochimica et cosmochimica acta》2004,68(22):4595-4618
Early Archean (3.46 Ga) hydrothermally altered basaltic rocks exposed near Marble Bar, eastern Pilbara Craton, have been studied in order to reveal geological and geochemical natures of seafloor hydrothermal carbonatization and to estimate the CO2 flux sunk into the altered oceanic crust by the carbonatization. The basaltic rocks are divided into basalt and dolerite, and the basalt is further subdivided into type I, having original igneous rock textures, and type II, lacking these textures due to strong hydrothermal alteration. Primary clinopyroxene phenocrysts are preserved in some part of the dolerite samples, and the alteration mineral assemblage of dolerite (chlorite + epidote + albite + quartz ± actinolite) indicates that the alteration condition was typical greenschist facies. In other samples, all primary minerals were completely replaced by secondary minerals, and the alteration mineral assemblage of the type I and type II basalts (chlorite + K-mica + quartz + carbonate minerals ± albite) is characterized by the presence of K-mica and carbonate minerals and the absence of Ca-Al silicate minerals such as epidote and actinolite, suggesting the alteration condition of high CO2 fugacity. The difference of the alteration mineral assemblages between basalt and dolerite is probably attributed to the difference of water/rock ratio that, in turn, depends on their porosity.Carbonate minerals in the carbonatized basalt include calcite, ankerite, and siderite, but calcite is quite dominant. The δ13C values of the carbonate minerals are −0.3 ± 1.2‰ and mostly within the range of marine carbonate, indicating that the carbonate minerals were formed by seafloor hydrothermal alteration and that carbonate carbon in the altered basalt was derived from seawater. Whole-rock chemical composition of the basaltic rocks is essentially similar to that of modern mid-ocean ridge basalt (MORB) except for highly mobile elements such as K2O, Rb, Sr, and Ba. Compared to the least altered dolerite, all altered basalt samples are enriched in K2O, Rb, and Ba, and are depleted in Na2O, reflecting the presence of K-mica replacing primary plagioclase. In addition, noticeable CO2 enrichment is recognized in the basalt due to the ubiquitous presence of carbonate minerals, but there was essentially neither gain nor loss of CaO. This suggests that the CO2 in the hydrothermal fluid (seawater) was trapped by using Ca originally contained in the basalt. The CaO/CO2 ratios of the basalt are generally the same as that of pure calcite, indicating that Ca in the basalt was almost completely converted to calcite during the carbonatization, although Mg and Fe were mainly redistributed into noncarbonate minerals such as chlorite.The carbon flux into the Early Archean oceanic crust by the seafloor hydrothermal carbonatization is estimated to be 3.8 × 1013 mol/yr, based on the average carbon content of altered oceanic crust of 1.4 × 10-3 mol/g, the alteration depth of 500 m, and the spreading rate of 1.8 × 1011 cm2/yr. This flux is equivalent to or greater than the present-day total carbon flux. It is most likely that the seafloor hydrothermal carbonatization played an important role as a sink of atmospheric and oceanic CO2 in the Early Archean. 相似文献
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接触热变质带的划分对变质岩变质过程的研究提供了有力的依据。基于京西羊屎沟地区地层中变质矿物组合及其空间分布情况,对该区的接触热变质带进行划分,并分析变质作用的形成阶段。由于燕山期房山岩浆岩体侵入,使围岩发生不同程度的接触热变质作用,形成各种特征变质矿物。在特定岩石类型中,特征变质矿物有规律的组合。采用偏光显微镜透射法和X射线衍射分析,分为透辉石-透闪石带、二云母带、红柱石白云母带和绢云母带,表明距离岩体由近至远,岩石变质程度由高到低呈分带现象。伴随着岩浆侵入不同阶段形成不同的特征变质矿物,将接触热变质作用分为5个渐进的阶段。 相似文献
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决定大区域成矿类型的究竟是什么，是否是岩浆岩的时代和成分、含矿岩基侵蚀断面的深度、沉积岩的成分和分散在其中的金属受到岩浆的同化作用？根据近年来最新研究资料，对这些问题作了否定回答，并提出了决定区域成矿特性的一系列因素。 相似文献
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The pegmatite complex of epi‐Permian age at Bismuth near Torrington, N.S.W., consists of an elongated intrusion of a granitoid quartz‐topaz rock (silexite) together with a series of pegmatites of varying composition. The principal pegmatite consists of orthoclase, biotite, quartz and beryl with concentric zoning passing outwards into fine‐grained biotite‐beryl rock containing a number of ore minerals: arsenides of Co, Fe and Ni, wolframite, bismuth, bismuthinite, molybdenite, joseite, cassiterite, rutile, uraninite and monazite. Small pegmatite veins issuing from this main body contain, in addition to the silicate minerals, high temperature tetrahedrite, chalcopyrite and sphalerite. A second group is characterised by quartz, orthoclase and beryl with occasional patches of tourmaline. Emplacement at no great depth is indicated by breccia veins and stock‐works filled with pegmatite. The origin of a silica hydromagma is considered in terms of existing experimental work and in terms of field occurrence. Structural evidence suggests that the quartzose intrusion preceded the injection of the pegmatite fluids, both being derived from the parent Mole biotite granite. 相似文献
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岩石与矿物的地球化学成分数据具有高维度特征。传统的岩矿地球化学成分研究主要采用二元/三元图解判别法,准确率不高,在数理统计方法上有欠缺。机器学习方法非常适用于对大样本高维度的岩矿成分数据进行数理统计处理。本文在介绍机器学习常见算法基本原理的基础上,总结近5年来国内外学者将机器学习方法应用于岩石矿物成分数据研究的实例,包括：① 根据矿物成分溯源其母岩（源岩）、判别矿床类型,② 新生代火山岩溯源,③ 判别变质岩原岩,④ 依据岩浆岩成分判别大地构造环境等。已有的研究实例显示,机器学习方法的准确度明显优于传统的低维度判别法。机器学习本质是分析大样本数据的高维度变量之间的相关、归类等多元统计问题。推广机器学习的应用需要建设开放获取（Open Access）的矿物、岩石成分数据库,同时全面实施开放研究（Open Research）的发表策略。 相似文献
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秘鲁马尔科纳(Marcona)铁矿区北部TA-02勘查区蕴含丰富的铜矿和铁矿资源,并伴生锌、钴等矿产资源。TA-02勘查区处于环太平洋构造-岩浆活动带的东侧,西南部发育有圣尼古拉斯(San Nicolás)岩基,胡斯塔(Justa)断裂控制了区内的铁、铜矿化及阳起石化蚀变带,是勘查区内(铁)铜矿体的主要控矿构造;胡斯塔断裂内常充填磁铁矿体、铜矿体及不同种类的脉岩,矿体形态以脉状为主;矿石中含铜矿物主要为黄铜矿,伴生/共生金属矿物主要为磁铁矿、赤铁矿、钴矿物、闪锌矿等,铜矿化与铁矿化具有高度的一致性,共/伴生关系密切,二者呈正相关关系,因此铜矿区呈现较高的磁异常;此外,矿体穿切地层,赋矿围岩无专属性,围岩蚀变以阳起石化蚀变为特征。研究认为,TA-02勘查区铜多金属矿属于IOCG型(氧化铁型铜-金)矿床。 相似文献
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江西兴国县地下水中富含偏硅酸,水资源丰富,但对矿泉水资源禀赋等研究相对薄弱,开展该县偏硅酸矿泉水水化学特征和健康功能研究,可为当地发展矿泉水产业、实施乡村振兴战略提供基础支撑。本文应用数理统计、水化学分析、离子比值等多种分析方法研究了兴国县潜在偏硅酸矿泉水的分布、水化学特征以及成因与物质来源,并基于感官指数和健康指数对其健康功能进行了评价。结果表明：潜在偏硅酸矿泉水主要分布在岩浆岩裂隙含水岩组、碎屑岩孔隙裂隙含水岩组和变质岩裂隙含水岩组中,这三类含水岩组的调查水样中,发现潜在偏硅酸矿泉水的比例分别为48.5%、45.7%、29.6%,且主要分布在海拔400m以下区域。潜在偏硅酸矿泉水的偏硅酸含量多集中在32~40mg/L之间,主要来自硅酸盐矿物的水解;在变质岩、岩浆岩裂隙含水岩组区,偏硅酸的富集以溶滤作用为主;在碎屑岩孔隙裂隙含水岩组区,偏硅酸的富集受溶滤作用和阳离子交替吸附作用共同影响。该县岩浆岩裂隙含水组区潜在偏硅酸矿泉水口感最佳,深层碎屑岩孔隙含水组区潜在偏硅酸矿泉水健康指数相对较高。本文认为,兴国县矿泉水勘查开发靶区宜以岩浆岩裂隙含水岩组区和深层碎屑岩孔隙裂隙含水岩组区为主。研究成果可为揭示兴国县偏硅酸矿泉水资源价值和功能提供参考。 相似文献
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湖南东坡矿田金船塘、红旗岭锡多金属矿床Rb-Sr、Sm-Nd同位素年代学研究 总被引：5，自引：0，他引：5
与千里山岩体有密切时空联系的东坡矿田是我国主要钨锡多金属矿产资源基地之一。在前人对千里山复式岩体成岩时代和金船塘与千里山岩体第一期似斑状花岗岩侵入活动有关的成矿作用研究的基础上,笔者选择金船塘及红旗岭矿床含矿石英脉中的石英和金船塘矿床矽卡岩矿石中的单矿物,进行石英流体包裹体Rb-Sr和矽卡岩矿物(包括符山石和石榴石)Sm-Nd同位素年代学研究,得出金船塘及红旗岭矿床石英流体包裹体Rb-Sr等时线年龄分别为133.4±5.9 Ma(MSWD=1.3)和143.1±8.7 Ma(MSWD=47),金船塘矿床矽卡岩矿物Sm-Nd等时线年龄为141±11 Ma(MSWD=0.27)。同位素年代学研究表明金船塘矿床至少存在164 Ma±、133~141 Ma两期成矿作用,在测定误差范围内,它们分别与千里山岩体第一期似斑状花岗岩(152 Ma)和第二期等粒黑云母花岗岩(136~137Ma)的侵入活动有关,而红旗岭矿床的成矿作用与千里山岩体第二期岩浆侵入活动有关。 相似文献
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甘肃小柳沟钨矿床矿石特征 总被引：3，自引：3，他引：3
文章对甘肃小柳沟钨矿床矿石类型、矿石结构构造、矿石矿物化学成分、主要有用组分赋存状态及其镶嵌关系、矿石比重特征进行了详细论述,指出(1)小柳沟钨矿床矿石类型简单;(2)矿石结构构造较为复杂;(3)矿石中矿物组成较复杂,种类多;矿石中有用元素主要有钨,此外含硫、铜、铋、钼、锌、锡等,钨是矿石中主要回收对象,而硫、铜、铋等具有一定的综合利用价值,可以考虑综合回收;(4)矿石中钨主要呈白钨矿存在,有少量钨华及黑钨矿;矿石中铜主要呈黄铜矿存在,有少量斑铜矿或辉铜矿;矿石中铋主要呈辉铋矿存在;矿石中钼主要呈辉钼矿存在,部分呈类质同象分布于白钨矿中,这部分钼难以用选矿方法分离;矿石中含硫矿物主要为黄铁矿,次为磁黄铁矿,其他含硫的矿物有黄铜矿、辉铋矿、辉钼矿,但是量都很少;(5)1号矿体及4号矿体所处矿化带中矿体的比重值不尽相同,进行资源/储量估算时应区别对待. 相似文献
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波孜果尔碱性岩型Nb-Ta-Rb-Zr-REE矿床位于塔里木克拉通北缘与南天山造山带的接合地段,是近年来在塔里木北缘碱性岩带中发现的规模最大的稀有-稀土综合性矿床。本文通过对含矿岩体中的独居石和晶质石墨包体开展成矿年代学和岩浆形成条件研究,结合含矿碱性岩全岩成分,揭示波孜果尔碱性岩型稀有-稀土金属矿床的岩石地球化学特征、晶质石墨对成岩/成矿的指示、稀土成矿时代和成矿动力学背景,并进一步总结区域成矿指示意义。研究发现,波孜果尔碱性岩以富含碱性暗色矿物(钠铁闪石和霓石)为特征,岩性以正长岩为主,有较高的稀土总量,富集轻稀土元素和高场强元素(Nb、Ta、Zr、Hf、Th、U等),亏损重稀土元素和Ba、Sr等大离子亲石元素,显示强烈的负Eu异常。通过对晶质石墨的研究发现,不同岩相组中石墨的拉曼谱峰相似,显示具有较高的结晶程度,岩浆演化从细晶到伟晶阶段,石墨的无序度增大,可能与烧绿石和锆石等含放射性元素矿物增多使得辐射加强的影响有关。估算石墨的结晶温度介于700~800℃之间,其形成早于碱性岩浆,指示碱性岩浆早期为还原环境,晚期趋于氧化。独居石LA-ICP-MS U-Th-Pb结果显示波孜果尔稀土矿化时代约为280Ma,结合前人已获得的锆石U-Pb年龄,表明波孜果尔碱性岩浆活动时间从~290Ma到280Ma,持续了至少10Myr。进一步研究发现,从时间和空间上,波孜果尔含矿碱性岩所在的碱性岩带形成与塔里木地幔柱有关。地幔柱就位诱发被先前俯冲物质交代富集稀有-稀土元素和挥发性成分的岩石圈地幔低程度部分熔融形成富成矿元素的碱性岩母岩浆,随后在岩浆演化晚期富集成矿。 相似文献
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The calc-alkaline Ladakh batholith (NW Himalayas) was dated to constrain the timing of continental collision and subsequent deformation. Batholith growth ended when collision disrupted subduction of the Tethyan oceanic lithosphere, and thus the youngest magmatic pulse indirectly dates the collision. Both U-Pb ages on zircons from three samples of the Ladakh batholith and K-Ar from one subvolcanic dike sample were determined. Magmatic activity near Leh (the capital of Ladakh) occurred between 70 and 50 Ma, with the last major magmatic pulse crystallizing at ca. 49.8+/-0.8 Ma (2sigma). This was followed by rapid and generalized cooling to lower greenschist facies temperatures within a few million years, and minor dike intrusion took place at 46+/-1 Ma. Field observations, the lack of inherited prebatholith zircons, and other isotopic evidence suggest that the batholith is mantle derived with negligible crustal influence, that it evolved through input of fresh magma from the mantle and remelting of previously emplaced mantle magmatic rocks. The sedmimentary record indicates that collision in NW Himalaya occurred around 52-50 Ma. If this is so, the magmatic system driven by subduction of Tethys ended immediately on collision. The thermal history of one sample from within the Thanglasgo Shear Zone (TSZ) was determined by Ar-Ar method to constrain timing of batholith internal deformation. This is a wide dextral shear zone within the batholith, parallel to the dextral, N 30 degrees W-striking crustal-scale Karakoram Fault. Internal deformation of the batholith, taken up partly by this shear zone, has caused it to deviate from it regional WNW-ESE trend to parallel the Karakoram Fault. Microstructures and cooling history of a sample from the TSZ indicate that shearing took place before 22 Ma, implying that (1) the history of dextral shearing on NW-striking planes in northern Ladakh started at least 7 m.yr. before the <15 Ma Karakoram Fault, (2) shearing was responsible for deviation of the regional trend of the Ladakh batholith, and (3) dextral shearing occured within a zone apporximately 100 km wide that includes the Ladakh batholith and portions of the younger Karakoram batholith. 相似文献
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A. O. Mazarovich V. A. Simonov A. A. Peive S. V. Kovyazin G. A. Tret'yakov Yu. N. Raznitsin G. N. Savel'eva S. G. Skolotnev S. Yu. Sokolov N. N. Turko 《Lithology and Mineral Resources》2001,36(5):460-462
The analysis of data on the location of hydrothermal fields, seismicity, and satellite altimetry evidences that in mid-ocean ridges with low spreading velocity hydrothermal fields tend to be grouped in areas with generally low seismic activity and at intersections of discontinuities and rift zones. Based on this assumption, the Sierra Leone Fracture Zone was studied in 2000 during cruise 22 of the R/V Akademik Nikolaj Strakhov.The study of gabbrodolerite and dolerite showed that sulfide ore minerals in them were formed both by hydrothermal and magmatic processes. The analysis of melt inclusions demonstrated that magmatic complexes formed from a high-temperature (1210–1255°C) low-potassium melt of the N-MORB type. Investigations of fluid inclusions revealed that gabbro and dolerite formed under the influence of an active hydrothermal system at a temperature of 205–226°C. Thus, the Sierra Leone Fracture Zone is considered to be perspective for the discovery of a new hydrothermal field. 相似文献
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Petrogenetic studies of carbonatites are challenging, because carbonatite mineral assemblages and mineral chemistry typically reflect both variable pressure–temperature conditions during crystallization and fluid–rock interaction caused by magmatic–hydrothermal fluids. However, this complexity results in recognizable alteration textures and trace-element signatures in the mineral archive that can be used to reconstruct the magmatic evolution and fluid–rock interaction history of carbonatites. We present new LA–ICP–MS trace-element data for magnetite, calcite, siderite, and ankerite–dolomite–kutnohorite from the iron-rich carbonatites of the 1.3 Ga Grønnedal–Íka alkaline complex, Southwest Greenland. We use these data, in combination with detailed cathodoluminescence imaging, to identify magmatic and secondary geochemical fingerprints preserved in these minerals. The chemical and textural gradients show that a 55 m-thick basaltic dike that crosscuts the carbonatite intrusion has acted as the pathway for hydrothermal fluids enriched in F and CO2, which have caused mobilization of the LREEs, Nb, Ta, Ba, Sr, Mn, and P. These fluids reacted with and altered the composition of the surrounding carbonatites up to a distance of 40 m from the dike contact and caused formation of magnetite through oxidation of siderite. Our results can be used for discrimination between primary magmatic minerals and later alteration-related assemblages in carbonatites in general, which can lead to a better understanding of how these rare rocks are formed. Our data provide evidence that siderite-bearing ferrocarbonatites can form during late stages of calciocarbonatitic magma evolution. 相似文献