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1.
大水沟碲矿床作为世界唯一碲独立成矿矿床,从它的偶然发现至今,一直倍受关注,但一直缺乏相关的探寻与对类似碲矿床的地球化学理论方法研究。石棉地区主要富集与基性岩浆活动有关的亲基性场元素或氧化物,Te、Bi成矿元素的整体含量不高,发生不同程度的贫化,碲在二叠系、志留系通化岩组、奥陶系大河边组、震旦系及二叠—三叠纪侵入岩中具有较好的局部富集和成矿潜力。虽然碲矿区内各元素含量水平不高,但Te、Bi平均含量高于石棉地区平均含量,接近西南五省背景值。根据碲成矿地质背景、石棉地区与碲矿区的地球化学特征,建立碲矿的地球化学找矿模型,运用模型为石棉地区提供了最具潜力的碲找矿靶区与方向,部分靶区已发现碲矿脉或矿化。 相似文献
2.
归来庄贫硫氧化型低温热液碲金矿床中金及碲化物矿物主要有自然金、碲金矿、碲金铜矿、碲银矿、碲金银矿、碲铅矿、碲镍矿、碲汞矿及自然碲等。金元素主要来源于泰山群山草峪组的片麻岩及寒武一奥陶系海相碳酸盐岩;碲元素主要是由铜石杂岩体的二长质、正长质等中偏碱性岩浆从地球深部的上地幔、下地壳带入矿区并进入由岩浆水及大气降水等组成的成矿热液中,与金元素形成碲金络合物进行搬迁、富集,因成矿体系的ｐＨ、Ｅｈ等物理化学 相似文献
3.
G. Paolo Sighinolfi 《Contributions to Mineralogy and Petrology》1974,46(3):189-200
Petrological and geochemical studies were carried out on early Precambrian carbonate rocks metamorphosed under granulite facies conditions from three areas of Bahia State (Brazil). Older rocks attributable to the Archean or lower Proterozoic consist of carbonates (mainly dolomite) and abundant, partially-serpentinized forsterite. Chemical data confirm their strong magnesian character and the almost complete absence of elements like Al, Ti, Na, K, Zr etc., which are normally found in the non-carbonate detrital part of impure carbonate rocks. Comparison with other carbonate rocks of similar silica content further emphasizes the scarcity of these elements. Samples of probably more recent origin belonging to migmatized complex of Central Bahia are more calcic in character and have a higher Sr and Ba content. The MgCO3 solvus thermometer in calcites coexisting with dolomite was determined both by chemical and X-ray procedures. Temperature values for carbonates under granulite facies range between 472 and 640° C. These temperatures seem to represent quench or recrystallization temperatures. The general geochemistry of carbonate rocks suggests two main hypotheses for their formation: a) chemical precipitation of pure carbonates during the Archean and later silica enrichment by metasomatic reactions; b) chemical co-precipitation in the Archean or early Proterozoic of carbonates and silica from silica-rich sea water. In this case precipitation would have occurred locally owing to increasing CO2 pressure (due, for example, to exhalative volcanism) or in limited evaporitic basins in areas of temporary stability bordering the continents. 相似文献
4.
Mohamed Abdallah Gad Darwish 《Environmental Earth Sciences》2017,76(23):804
The Marahiq area represents a portion of the Pan-African belt from the Neoproterozoic age in south Egypt and includes metamorphosed ultramafic rocks, metavolcanic rocks, and granodiorite pluton. The area is characterized by the ancient abandoned Au mine and the recent active talc mines. The present paper provides a preliminary assessment of stream sediments for gold (Au) placer and environmental hazard. Steam sediments from 36 stations were analyzed using ICP-MS for determining the concentration of 53 elements. Various statistical techniques, graphical representations, a set of complementary sediment quality assessment methods, and different mapping methods have been applied. The results showed that Au and the investigated elements were influenced by long history of the ancient mining activities and weathering processes, leading to elevate Au and some heavy metal(loid)s concentrations and exhibit enrichment ratios as follows: Te > As > Au > Cu > Cd > Co > Ni > V. Whereas Cd, Co, and V were attributed to geogenic origin, As, Au, Cu, Ni, and Te were derived from anthropogenic mining activities. It is found that the anomalies of Au and the element of interest are indicative of Au placer and point out a new perspective Au-sulfide mineralization hosted along the favorable tectonic zones that were the main source of Au placer. Both As and Te are good pathfinders to explore Au placer and related mineralization. Environmentally, the excess of As, Cu, Ni, and Te could generate moderate levels of contamination and low level of ecological risk in the sediments. Although As, Cu and Ni posed medium–low potentially adverse effects and low toxicity levels, they cannot cause harmful influences on biological life. Accordingly, streambed sediments are considered as safe and acceptable as inoffensive materials for environmental management. Overall, this study is as reference values for governmental organizations for appraising future environmental pollution in the area. Also, it is fruitful for Au placer and promising with success for Au exploration along the shear zones and strike-slip faults. 相似文献
5.
Adriana Heimann Paul G. Spry Graham S. Teale Colin H. H. Conor Norman J. Pearson 《Mineralogy and Petrology》2011,101(1-2):49-74
Garnet-rich rocks occur throughout the Proterozoic southern Curnamona Province, Australia, where they are, in places, spatially related to Broken Hill-type Pb-Zn-Ag deposits. Fine-scale bedding in these rocks, their conformable relationship with enclosing metasedimentary rocks, and their enrichment in Mn and Fe suggest that they are metamorphosed chemical precipitates. They formed on the floor of a 1.69?Ga continental rift basin from hydrothermal fluids mixed with seawater and detritus. Garnet in garnet-quartz and garnet-amphibole rocks is generally light rare earth element (LREE) depleted, and has flat heavy REE (HREE) enriched chondrite-normalized REE patterns, and negative Eu anomalies (Eu/Eu*?<?1). Garnet in garnet-rich rocks from the giant Broken Hill deposit has similar REE patterns and either positive (Eu/Eu*?>?1) or negative Eu anomalies. Manganese- and Mn-Ca-rich, Fe-poor garnets in garnetite, garnet-hedenbergite, and garnet-cummingtonite rocks at Broken Hill have Eu/Eu*?>?1, whereas garnet in Mn-poor, Fe-rich quartz garnetite and quartz-garnet-gahnite rocks from Broken Hill, and quartz garnetite from other locations have Eu/Eu*?<?1. The REE patterns of garnet and its host rock and interelement correlations among REEs and major element contents in garnet and its host rock indicate that the Eu anomaly in garnet reflects that of its host rock and is related to the major element composition of garnet and its host rock. The value of Eu/Eu* in garnet is related to its Mn, Fe, and Ca content and that of its host rock, and the distribution of REEs among garnet and accessory phases (e.g., feldspar). Positive Eu anomalies reflect high amounts of Eu that was preferentially incorporated into Mn- and Mn-Ca-rich oxides and carbonates in the protolith. In contrast, Eu/Eu*?<?1 indicates the preferential discrimination against Eu by Fe-rich, Mn-poor precursor minerals. Precursors to Mn-rich garnets at Broken Hill formed by precipitation from cooler and more oxidized hydrothermal fluids compared to those that formed precursors to Mn-poor, Fe-rich garnet at Broken Hill and the other locations. Garnet from the Broken Hill deposit is enriched in Zn (> 400?ppm), Cr (> 140?ppm), and Eu (up to 6?ppm and positive Eu anomalies), and depleted in Co, Ti, and Y compared to garnet in garnet-rich rocks from other localities. These values, as well as MnO contents ?>?15 wt. % and Eu/Eu*?>?1 are only found at the Broken Hill deposit and are good indicators of the presence of Broken Hill-type mineralization. 相似文献
6.
碲（Te）属于稀散元素,是我国的战略性关键矿产资源之一,富碲化物金矿床是碲元素的重要载体.将富碲化物金矿床划分为3种成因类型,分别为造山型金矿床、浅成中-低温热液型金矿床以及与碱性岩浆岩有关的金矿床.富碲化物金矿床可以形成于岛弧、大陆边缘、弧后盆地、绿岩带等多种构造环境,常受区域性断裂构造控制,其围岩专属性不强,矿床中存在大量碲化物,与自然金和硫化物伴生产出.成矿作用常可划分为3个阶段:石英-黄铁矿阶段、石英-多金属硫化物-碲化物阶段、石英-碳酸盐阶段,其中金和碲主要在第二阶段发生沉淀富集.成矿流体一般为中-低温、中-低盐度,呈弱酸性-中性,具有较高的fTe2.富碲化物金矿床中的碲主要来源于地幔、岩浆热液和赋矿围岩.碲在流体中可以呈碲氯络合物、碲硫络合物、碲氢络合物等形式迁移,也可呈气态迁移.引起碲发生沉淀的因素主要为温度或/和压力的变化、水岩反应、流体混合、流体不混溶（沸腾）、含碲气体的冷凝以及多因素的叠加.在碲的成矿作用研究中,应重视碲化物结构和成分的微区原位分析、碲同位素分析以及热力学分析. 相似文献
7.
Extreme Enrichment of Tellurium in Deep-Sea Sediments 总被引：2，自引：0，他引：2
LI Yanhe WANG Yimin SONG Hebin and YUE Guoliang Laboratory of Isotope Geology Ministry of Land Resources Beijing E-mail: lyh@mx.cei.gov.cn Institute of Mineral Resources Chinese Academy of Geological Sciences Beijing National Geoanalysis Center Beijing 《《地质学报》英文版》2005,79(4):547-551
Tellurium is a sort of scattered rare element on the earth. Its concentration is very low in earth＇s crust, only 1.0 ng/g. However, it has extremely high abundance in Co-rich crusts, marine polymetallic nodules, deep-sea sediments and aerolites. To find out the origin of tellurium enrichment in deep-sea sediments, we analyzed and compared tellurium concentrations and helium isotope compositions in the magnetic parts and those in the bulk parts of deep-sea sediments. The result indicates that the helium content, 3He/4He ratio and tellurium concentration are obviously higher in the magnetic parts than those in the bulk parts. The 3He abundance varies synchronously with the tellurium concentration. 3He and Te have a distinct positive correlation with each other. It is the first time that the paper brings forward that the extreme enrichment of tellurium in deep-sea sediments, like helium isotope anomalies, probably results from the input of interplanetary dust particles （IDPs）. Similarly, the extreme enrichment of tellurium in marine polymetallic nodules and Co-rich crusts is possibly related to IDPs. 相似文献
8.
There is very little understanding of tellurium (Te) distribution and behaviour in sedimentary rocks. A suite of 15 samples of reduction spheroids (centimetre‐scale pale spheroids in otherwise red rock), including samples from eight localities in Triassic red beds across the British Isles, were mapped for Te using Laser Ablation–Inductively Coupled Plasma–Mass Spectrometry. Almost all showed enrichment in Te in the cores of the spheroids relative to background red bed concentrations, by up to four orders of magnitude. Some were also enriched over background in gold and/or mercury. In one case, discrete telluride minerals were recorded. The data show that Te is mobile and can be concentrated in low‐temperature sedimentary environments, controlled by redox variations. The consistency in enrichment across widely separate localities implies that the enrichment is a normal aspect of red bed diagenesis and so likely to be controlled by a ubiquitous process, such as microbial activity. 相似文献
9.
1 Introduction China’s widespread marine carbonate rock series are mostly characterized by intensive thermal evolution and low abundance of organic matter, especially the Lower Paleozoic carbonate rocks have experienced multi-episodes of tectonics and ap… 相似文献
10.
A. A. Makhnach B. G. Pokrovsky O. V. Murashko O. L. Petrov 《Lithology and Mineral Resources》2020,55(1):24-35
The behavior of stable carbon and oxygen isotopes in carbonates during the deposition and diagenesis of sediments in the bioproductive Upper Famennian Pripyat Trough (southern Belarus) is discussed. Limestones and clayey limestones (Corg 0.92 ± 0.11%) are characterized by very low δ13C values (–9.6 ± 0.3‰). Parental sediments of these rocks were deposited in the shallow-water zone during slow downwarping episodes of the seafloor. Lithification of the sediments took place in oxidative conditions of the diagenesis zone. Organic matter was actively oxidized by free oxygen. Carbon dioxide with isotopically light organic carbon formed in this process was used during the crystallization of diagenetic carbonates that are visually indiscernible from the sedimentational variety. Marls, clayey marls, and carbonate-bearing clays (Corg 6.02 ± 0.80%) are characterized by δ13C values as high as –3.5 ± 0.6‰. In combustible shales (Corg >10%), δ13C value is ‒1.2 ± 0.6‰). The clayey rocks mark the episodes of sedimentation in relatively deep-water conditions that appear during the uncompensated sagging of the basin floor. The diagenetic zone with free oxygen was significantly decreased or absent at all. Here, oxygen of marine sulfates was the main or single oxidizer of organic matter (sulfate reduction). The sulfate oxygen is a weaker oxidizing agent than free oxygen. Therefore, much more organic matter was retained and fossilized in clayey rocks than in carbonate rocks. Organic carbon released during the sulfate reduction and mobilized later for the diagenetic carbonate formation was insufficient for the significant decrease of δ13C values relative to the marine carbonate standard. Isotopic composition of carbonate oxygen in the studied rocks is invariable and does not depend on the content of clay and organic matter. In these rocks, δ18O values are at the level (approximately –5‰) shown for the Famennian in the Global Chemostratigraphic Chart. This fact is consistent with the supposition that oxygen isotope composition of atmospheric precipitates, which influenced the rock formation via continental flow, is close to that of sea water in low latitudes where the territory of Belarus was located in the Late Devonian. 相似文献
11.
Most of the economic ore deposits of Ecuador are porphyry-Cu and epithermal style gold deposits associated with Tertiary continental arc magmatism. This study presents major and trace element geochemistry, as well as radiogenic isotope (Pb, Sr) signatures, of continental arc magmatic rocks of Ecuador of Eocene to Late Miocene (~50–9 Ma, ELM) and Late Miocene to Recent (~8–0 Ma, LMR) ages. The most primitive ELM and LMR rocks analyzed consistently display similar trace element and isotopic signatures suggesting a common origin, most likely an enriched MORB-type mantle. In contrast, major and trace element geochemistry, as well as radiogenic isotope systematics of the whole sets of ELM and LMR samples, indicate strikingly different evolutions between ELM and LMR rocks. The ELM rocks have consistently low Sr/Y, increasing Rb/Sr, and decreasing Eu/Gd with SiO2, suggesting an evolution through plagioclase-dominated fractional crystallization at shallow crustal levels (<20 km). The LMR rocks display features of adakite-type magmas (high Sr/Y, low Yb, low Rb/Sr) and increasing Eu/Gd and Gd/Lu ratios with SiO2. We explain the adakite-type geochemistry of LMR rocks, rather than by slab melting, by a model in which mantle-derived melts partially melt and assimilate residual garnet-bearing mafic lithologies at deeper levels than those of plagioclase stability (i.e., >20 km), and most likely at sub-crustal levels (>40–50 km). The change in geochemical signatures of Tertiary magmatic rocks of Ecuador from the ELM- to the LMR-type coincides chronologically with the transition from a transpressional to a compressional regime that occurred at ~9 Ma and has been attributed by other investigations to the onset of subduction of the aseismic Carnegie ridge.The major districts of porphyry-Cu and epithermal deposits of Ecuador (which have a small size, <<200 Mt, when compared to their Central Andean counterparts) are spatially and temporally associated with ELM magmatic rocks. No significant porphyry-Cu and epithermal deposits (except the epithermal high-sulfidation mineralization of Quimsacocha) appear to be associated with Late Miocene-Recent (LMR, ~8–0 Ma) magmatic rocks. The apparent infertility of LMR magmas seems to be at odds with the association of major porphyry-Cu/epithermal deposits of the Central Andes with magmatic rocks having adakite-type geochemical signatures similar to LMR rocks. The paucity of porphyry-Cu/epithermal deposits associated with LMR rocks might be only apparent and bound to exposure level, or real and bound (among other possibilities) to the lack of development of shallow crustal magmatic chambers since ~9 Ma as a result of a prolonged compressional regime in the Ecuadorian crust. More work is needed to understand the actual metallogenic potential of LMR rocks in Ecuador.Editorial handling: J. Richards 相似文献
12.
The average K, Rb, T1 abundances in 26 Mid-Atlantic Ridge basalts are 2,660 p.p.m., 6.6 p.p.m., 205 p.p.b.; abundances in 19 Hawaiian basalts and other rocks are 12,430 p.p.m., 32 p.p.m., 84 p.p.b.; 20 continental rocks (mostly basic) average 12,580 p.p.m., 56 p.p.m., 305 p.p.b. Abundances were obtained also for 8 meteorites. 相似文献
13.
14.
Alteration and primary geochemical dispersion associated with the Bulletin lode-gold deposit, Wiluna, Western Australia 总被引：1，自引：0，他引：1
The Bulletin lode-gold deposit is within the northernmost part of the Norseman–Wiluna greenstone belt in the Archaean Yilgarn Block, Western Australia. It is located within a brittle–ductile shear zone and hosted by tholeiitic metavolcanic rocks. Syn-metamorphic wallrock alteration envelops the gold mineralisation and is pervasive throughout the entire shear zone and extends up to 150 m into the undeformed wallrocks. Alteration is characterised by the sequence of distal chlorite–calcite, intermediate calcite–dolomite, outer proximal sericite and inner proximal dolomite–sericite zones. The thickness of the alteration envelope, and the occurrence of dolomite in the alteration sequence, can be used as a rough guide to the width, extent and grade of gold mineralisation, because a positive correlation exists between these variables. Mass transfer evaluations indicate that chemical changes related to the wallrock alteration are similar in all host rocks: in general, Ag, As, Au, Ba, CO2, K, Rb, S, Sb, Te and W are enriched, Na and Y are depleted, and Al, Cr, Cu, Fe, Mg, Mn, Nb, Ni, P, Se, V, Zn and Zr are immobile, while Ca, Si and Sr show only minor or negligible relative changes. The degree of mobility of each component increases with proximity to gold mineralisation. The largest potential exploration targets are possibly defined by regional As (>6 ppm) and Sb (>0.6 ppm) anomalies. These anomalies, if real, extend laterally for >150 m from the mineralised shear zone into areas of apparently unaltered rocks. Anomalies defined by Te (>10 ppb), W (>0.6 ppm), carbonation indices, local enrichment of Sb (>2.0 ppm) and As (>28 ppm), and potassic alteration indices also form significant exploration targets extending beyond the HJB shear zone and the Au anomaly (>6 ppb) and, locally, into apparently unaltered rock. Gold, itself, has a restricted dispersion, with an anomaly extending for 1–35 m from ore, and being restricted to within the shear zone itself. Amongst individual geochemical parameters, only As and Sb define significant, consistent and smooth trends (vectors) when laterally approaching the ore. However, the respective dimensions of individual geochemical anomalies can be used as an extensive, though stepwise, vector towards ore. 相似文献
15.
P. Voudouris 《Mineralogy and Petrology》2006,87(3-4):241-275
Summary Several magmatic-hydrothermal systems in northeastern Greece (western Thrace and Limnos Island) are highly enriched in tellurides
which, in addition to native gold and electrum, represent major carriers of precious metals in the ore. Deposition near the
porphyry-epithermal transition for several systems is indicated by field relations and by the presence of key minerals (Pb-
and Ag-rich tellurides, Bi-sulfosalts and Bi-tellurides/tellurosulfides). Hessite, stützite, sylvanite, petzite, coloradoite,
altaite, unnamed Ag-sulfotelluride, native tellurium and electrum are abundant in intermediate sulfidation quartz-carbonate
veins together with zincian tetrahedrite-group minerals, chalcopyrite and galena. The presence of hessite, goldfieldite, native
gold and enargite or famatinite suggests deposition at a high sulfidation state. The main stage of telluride deposition took
place at ∼275 °C at log fTe2 values of −8.5 to −7.1 and log fS2 values of −10.8 to −9.0, based on the Fe-content in sphalerite and the sulfide-telluride mineralogy. The close spatial association
of telluride mineralization with intrusive centers of intermediate composition, the base metal enrichment and the trace element
signature involving Au, Ag, Te, Bi, Sn and Mo suggest that ore-forming components were introduced at the porphyry-epithermal
transition. Potential sources of tellurium are the high-K calc-alkaline (western Thrace) to shoshonitic (Limnos) intrusive
rocks. 相似文献
16.
17.
The chemistry and mode of occurrences of native tellurium in the epithermal gold ores from Teine, Kobetsuzawa, Mutsu, Kawazu, Suzaki and Iriki in Japan are examined. Mineral assemblages in contact with native tellurium are: quartz‐sylvanite at Teine, quartz‐hessite‐sylvanite‐tellurantimony at Kobetsuzawa, quartz at Mutsu, quartz‐stutzite‐hessite‐sylvanite‐tetradymite at Kawazu, quartz at Suzaki, and quartz‐goldfieldite at Iriki. The peak patterns of XRD for native tellurium from these six ores are nearly identical to that of JCPDS 4–554. Their chemical compositions of Te range from 98.16 to 100.73 wt.%, showing nearly pure tellurium. Other elements detected are: Se of 0–0.85 and Cu of 0–0.74 at Teine, Sb of 0.45–0.47 and Se of 0.19–0.27 at Kawazu, Se of 0.22–1.11 and Sb of 0–0.49 at Suzaki, and Cu of 0.69–0.98, As of 0.22–0.28 and Bi of 0–0.22 wt.% at Iriki. No other elements are detected in the ores of Kobetsuzawa and Mutsu. The ranges of associated minor compositions are consistent with those of the experimental phase. The differences would be related to associate minerals. The mineral assemblages in these ores agree well with the previously proposed experimental phase relations in Au‐Ag‐Te ternary system for 120–280°C. The Suzaki ore has high Te‐Au assemblage: from calaverite‐sylvanite‐krennerite via native tellurium to petzite, with changing mineralization stage, whereas the Kobetsuzawa and the Kawazu ores have high Te‐Ag assemblage of tellurium‐hessite, and native tellurium‐stutzite‐hessite‐sylvanite, respectively. The Teine ore has intermediate assemblage of native tellurium‐sylvanite. The mineral assemblages in the Au‐Ag‐Te system are related to the hydrothermal environment especially to the pH condition, i.e. Au rich assemblages under acidic and Ag rich assemblages under intermediate pH conditions, being supported by alteration mineral species. The other telluriferous epithermal gold deposits not in association with native tellurium such as Agawa, Date, Takeno, Chugu, Chitose, Sado and Kushikino are estimated to have been formed under higher pH conditions as adularia and calcite occur in these deposits. The pH‐Eh diagram for aqueous tellurium species and tellurium minerals at 250°C indicates that the region of native tellurium occurs between those of aqueous telluride and tellurous species at lower pH, being consistent with their mineral assemblages in ores and alteration envelopes. 相似文献
18.
Abstract: Carbonate rocks of Cambrian (18 samples) and lower-middle Ordovician (11 samples) ages from South Korea were analyzed for sulfur contents of structurally substituted sulfate (SSS) and sulfides and their δ34 S values. The δ34 S values of SSS ranging from +25.9 to +45.2 permil, are averaged as +33.6 and +33.5 permil for the Cambrian and Ordovician rocks, respectively, which indicate high δ34 S values of the Cambro-Ordovician seawater. The SSS contents in the carbonate rocks are low being 2.9 to 17.3 ppm S (averaged as 7.0 ppm S). Sulfide sulfur, on the contrary, is much abundant containing 3 to 1,880 ppm S and the δ34 S values range widely between –17.6 and +31.1 permil. Sulfide sulfur of the studied rocks excluding impure carbonates has an average content of 187 ppm S and δ34 S value of +12.8 permil (n=24). The estimated δ34 S (sulfate–sulfide) values, which range from 13.8 to 25.4 permil in general with a few exceptions from 36.5 up to 52.3 permil for some impure carbonates, may provide evidence for the persistent oceanic anoxia with its temporary recovery during the Cambro-Ordovician time.
The SSS and sulfide sulfurs have often higher δ34 S values than the Mesozoic-Cenozoic ore sulfur (Ishihara et al., 2000). Since carbonate rocks are very reactive with circulating hydrothermal ore solution, high δ34 S values of the Korean ore deposits might be caused to some extent by 34 S enrichment from the host carbonates, resulting in the low SSS contents observed. 相似文献
The SSS and sulfide sulfurs have often higher δ
19.
武山铜矿床是长江中下游成矿带九瑞矿集区内典型的层控-接触带矽卡岩型铜多金属矿床,铜资源量达到大型,此外还共生硒、碲、钴、镓、铊等关键金属矿产,具备良好的矿产资源综合利用前景,但矿床中关键金属的分布规律、赋存状态和富集机制等研究尚未开展。本文以武山铜矿床为研究对象,系统采集了矿床南矿带接触带矽卡岩型矿体3条勘探线(W3-2、S4-2、N6-1)、北矿带层控硫化物型矿体3条勘探线(E9-2、E2-1、W4-1)和层控矽卡岩型矿体1条勘探线(E7-3)代表性岩矿石样品。通过光学显微镜和扫描电镜的观察,结合全岩地球化学和矿物原位LA-ICP-MS分析,查明了矿床中硒、碲、钴等关键金属的空间分布规律与赋存状态,初步探讨了硒、碲、钴的迁移沉淀机制。研究结果表明矿床中伴生硒、碲、钴的估算资源量分别为5513t、611t和9597t,均达到大-中型规模;武山矿床是成矿带内硒含量最高、潜在资源量最大的矿床。北矿带矿体中Se、Te、Co含量明显高于南矿带,北矿带中部成矿中心向东西远端,矿体中Se、Te、Co含量规律性增高。矿石中Se、Te、Co含量与S含量具有较强的正相关性,矿石中硫化物的含量是关键金属含量主要控制指标;Se和Co富集于含铜黄铁矿矿石、含铜白云岩矿石、含铜矽卡岩矿石(高硫)中;Te富集于含铜黄铁矿矿石和含铜白云岩矿石中。矿床中硒、碲主要以独立矿物和硫化物中类质同象替换两种赋存形式,钴则主要以Co^(2+)类质同象形式进入黄铁矿矿物晶格。矿床中硒、碲随着成矿流体温度降低、硫逸度升高、氧逸度降低、pH值升高逐渐沉淀富集;钴主要随着硫化物的沉淀富集在黄铁矿中。 相似文献
20.
Published data on extremely magnesian olivine (> 96 mol.% forsterite) in igneous rocks were generalized and compared with data of new high-precision electron probe microanalyses of olivine from oxidized lavas of the Tolbachik Volcano (Kamchatka), chromitites from the Ray-Iz deposit (Russia), alkaline ultrabasic lavas from San Venanzo volcanoes (Italy), and skarns from the Kuh-i-Lal deposit (Tajikistan). All the found olivines resulted from low-temperature processes, such as subsurface oxidation, interaction with carbonates, and subsolidus re-equilibration. Low-temperature formation of olivine is reflected in its structure (hematite lamellae and abundance of inclusions of ore minerals) and abnormal contents of minor components (Mn, Ni, and Ca). The Mg content of olivine increases under the influence of postmagmatic processes and can be manifested in different rocks. This gives grounds to refine the genesis of olivine of exotic composition (93-96 mol.% forsterite) in some kimberlites, komatiites, and peridotites. 相似文献