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1.
L. T. Rakov 《Geochemistry International》2006,44(10):1004-1014
Mechanisms of the incorporation of isomorphic impurities of Al, Ti, and Ge into quartz were studied by EPR techniques. For
this purpose, laboratory experiments were carried out on quartz annealing, which allowed us to model the processes of impurity
atom introduction into the quartz lattice. The investigation of the kinetics of these processes showed that they are described
by diffusion-controlled reactions. In many samples, a proportional relationship was observed between the concentrations of
Al and Ti impurities incorporated into the quartz structure during laboratory annealing. A comparison of the experimental
results with the character of the natural distribution of isomorphic impurities in quartz revealed their similarity. Based
on the analysis of the results of our investigations, two main mechanisms were proposed for isomorphic substitutions in quartz.
One of them is referred to as the capture mechanism and corresponds to the incorporation of isomorphic impurities during mineral
formation. The second, diffusion mechanism operates after the crystallization of quartz. The isomorphic impurities incorporated
into the quartz structure by this mechanism are either formed through the decomposition and transformation of composite complexes
or as a result of diffusion from crystalline and gas-liquid inclusions. It was suggested that both mechanisms are responsible
for the incorporation of Al and Ge impurities into the mineral lattice, whereas Ti is introduced mainly by the diffusion mechanism.
The accounting for the mechanisms of isomorphic substitutions provides a means to significantly increase the reliability of
the interpretation of genetic information recorded in the distribution of structural impurities in quartz.
Original Russian Text ? L.T. Rakov, 2006, published in Geokhimiya, 2006, No. 10, pp. 1085–1096. 相似文献
2.
Vsevolod Prokofiev Ivan Baksheev Lidiya Zorin Boris Belyatsky Vladimir Ustinov Nadezhda Krivitskaya 《地学前缘(英文版)》2012,3(1):59-71
Zoned tourmaline（schorl-dravite） in the matrix of hydrothermal explosive breccia and ore veins in gold deposits,Chita region.Eastern Transbaikalia.Russia,are associated with Na- and K-rich porphyry-type subvolcanic intrusives.δ18O values of tourmaline from three gold deposits（Darasun. Talatui,Teremkinskoye） are +8.3‰,+7.6‰,and +6.0‰and calculatedδ18O values of fluids responsible for the tourmalinization are +7.3‰,+7.7‰,and +4.2‰,respectively.These data imply an igneous fluid source,except at the Teremkin deposit where mixing with meteoric water is indicated.Wide ranges of Fe3+/Fetot,and the presence of vacancies characterize the Darasun deposit tourmaline indicating wide ranges of f（O2） and pH of mineralizing fluids.Initial stage tourmalines from the gold deposits of the Darasun ore district are dravite or high mg schorl.Second stage tourmaline is characterized by oscillatory zoning but with Fe generally increasing towards crystal rims indicating decreasing temperature.Third stage tourmaline formed unzoned crystals with xMg（mole fraction of Mg） close to that of the hrst stage tourmaline,due to a close association with pyrite and arsenopyrite.From Fe3+/Fetot values,chemical composition and crystallization temperatures.logf（O2） of mineralizing fluids ranged from ca.—25 to—20. much higher than for the gold-bearing beresite—listvenite association,indicating that tourmalinization was not related to gold mineralization. 相似文献
3.
I. V. Chernyshev V. Yu. Prokof’ev N. S. Bortnikov A. V. Chugaev Yu. V. Goltsman V. A. Lebedev Yu. O. Larionova L. D. Zorina 《Geology of Ore Deposits》2014,56(1):1-14
The Darasun ore field situated in the southern West Stanovoi Terrane near the Mongolia-Okhotsk Suture comprises the Darasun (>100 t Au), Talatui (～38.2 t Au), and Teremki (3 t Au) lode gold deposits. In the opinion of many researchers, the Darasun deposit is spatially and paragenetically linked to granodiorite porphyry of the Amudzhikan Complex and related metasomatic rocks (beresites). Whole-rock samples of granodiorite porphyry, monomineralic fractions of plagioclase, K-feldspar, and biotite, as well as sericite from beresite (26 samples in total), were analyzed by the Rb-Sr method. Eight biotite and sericite samples were analyzed by the K-Ar method. The Rb-Sr mineral isochrons obtained for individual granodiorite porphyry samples yielded initial 87Sr/86Sr ratios varying from 0.70560 to 0.70591. The consistent results of both methods allowed us to accept the ages of granodiorite porphyry and beresite as 160.5 ± 0.4 and 159.6 ± 1.5 Ma, respectively. The age of granodiorite porphyry of the Amudzhikan Complex of 160.5 ± 0.4 Ma corresponds to the boundary between the Early and Middle Jurassic and marks the completion of collision between the East Siberian and Mongolia-China continents and related orogeny. Since that time, the eastern Transbaikal region has been involved in the postorogenic (within-plate) stage of evolution, characterized by the formation of large gold, uranium, and other ore deposits. 相似文献
4.
V. Yu. Prokof’ev L. D. Zorina V. A. Kovalenker N. N. Akinfiev I. A. Baksheev A. N. Krasnov G. A. Yurgenson N. V. Trubkin 《Geology of Ore Deposits》2007,49(1):31-68
The mineral composition of the Talatui gold deposit has been studied with modern methods. Previously unknown minerals (ilmenite, siegenite, glaucodot, wittichenite, matildite, hessite, pilsenite, zircon, tremolite, cummingtonite, hercynite, and goethite) have been identified in the ore. A high Re content has been detected in molybdenite. The spatiotemporal separation of Au and Ag is caused by different mineral species of these elements and their diachronous precipitation during the ore-forming process. Gold crystallized along with early mineral assemblages, beginning from virtually pure gold (the fineness is 996). Silver precipitated largely at the end of the process as hessite (Ag2Te) and matildite (AgBiS2). The temperature of ore deposition varied from 610 to 145°C, the pressure was 3370–110 bar, and the salt concentration ranged from 56.3 to 0.4 wt % NaCl equiv. The heterogeneous state (boiling) of fluid at the early stages has been documented. The chemical and isotopic compositions of the fluid testify to its magmatic nature and the participation of meteoric water at late stages in the ore-forming process. Thermodynamic modeling reproduces the main specific features of ore formation, including separation of Au and Ag. A physicochemical model of the gold mineralization in the Darasun ore district has been proposed. On the basis of several attributes, the Talatui deposit has been referred to the prophyry gold-copper economic type. 相似文献
5.
V. I. Gvozdev K. N. Dobroshevsky A. S. Vakh N. A. Goryachev V. A. Stepanov D. G. Fedoseev 《Russian Journal of Pacific Geology》2016,10(1):34-49
Original data on the ore composition are obtained by studying samples from mining workings. In terms of mineral composition, gold-productive veinlets are subdivided into three types: sulfide–quartz, sulfide–carbonate–quartz, and sulfide. The wall-rock metasomatites and typomorphic features of the minerals are studied and the genetic problems of the ores and deposit are discussed. It is established that the Malinovka deposit is ascribed to the gold–tourmaline type (gold–quartz formation), which is identified for the first time in Primorye. In terms of many parameters, the ores of this type are close to those of the large deposits from the Transbaikalian and Amur regions (Klyuchevsky, Kariy, Kirov, Darasun, and others), which are genetically related to granitoid magmatism. 相似文献
6.
Quartz from granites, greisens and quartz veins from a 1596 m long vertical section through the Cínovec/Zinnwald Li-Sn-W deposit (Czech Republic) was studied using cathodoluminescence (CL) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP MS). The trace contents of Al, Ti, Li and the Ge/Ti and Al/Ti values in quartz reflect the degree of fractionation of parental melt from which primary quartz crystallized. From the biotite granite to the younger zinnwaldite granite, quartz is characterized by increasing contents of Al (from 136–176 to 240–280 ppm) and decreasing Ti (from 16–54 to 6–14 ppm), while the contents of Li and Ge are similar (15–36 and 0.8–1.7 ppm, respectively). Quartz of the greisen stage and vein stage is poor in all measured elements (26–59 ppm Al, 0.5–1.6 ppm Ti, 2–13 ppm Li, 0.8–1.6 ppm Ge). The youngest low-temperature quartz forming thin coatings in vugs in greisen and veins differs in its extreme enrichment in Al (>1000 ppm) and Li (∼100 ppm) and very low Ti (<1 ppm). Within the greisen, remnants of primary magmatic quartz should be distinguished from metasomatic greisen-stage quartz in their higher intensity of CL and relatively higher Ti contents. A part of primary magmatic quartz may by secondarily purified via infiltration of hydrothermal fluids and dissolution–reprecipitation processes. Such quartz parallels newly formed greisen-stage quartz in its chemical and CL properties; the share of greisen-stage quartz may by therefore overestimated. 相似文献
7.
石英是一种在地壳上大量分布,有着广泛工业用途和广阔应用前景的矿物。当石英晶体形成演化时,受结晶时环境条件、流体性质、结晶后遭受改造(如变质作用、构造变形和热扰动等)等影响,杂质元素如P、Ti、Ge、Al、B、Be、Ca、Na、K、H、Li等会或多或少存在于石英晶体中,因此在自然界不存在纯SiO2组分的石英。同时,基于石英的微量元素组成,可以反演石英源区和形成演化过程,并用于研究岩石及矿床成因等科学问题。石英晶体内部杂质元素以类质同象替代、气液包裹体、矿物包裹体(不能按尺度分,应该按照状态划分存在形式)3种形式存在。石英中杂质元素的种类、含量、赋存形式,特别是包裹体特征将直接影响石英资源的品质和工业用途。本文还系统地阐述了石英的发光特性、工艺性能以及高纯石英的质量分类与标准和高纯石英原料来源等方面的内容。在本研究中,通过光学显微镜和激光拉曼测试,初步地查明了苏北张锦庄石英砂和广西姑婆山花岗岩石英中流体包裹体的分布和矿物包裹体的种类,这是开展后续研究的基础。高纯石英是优质石英资源经纯化加工得到的高品质石英原材料,可用于石英玻璃、石英坩埚、半导体、高温灯管、光纤、精密光学、微电子和太阳能等高新技术产业中。研究高纯石英原料的评价体系、理想源岩和形成机制有益于持续性地供给高纯石英原料, 极大地提高了石英原料的工业附加值。 相似文献
8.
《Russian Geology and Geophysics》2007,48(11):923-932
The face effect was observed in all individual compounds with beryl structure having grown at a rate of 1–8 unit cells a second, with spontaneous crystallization in the system beryl (or cordierite)–Mg,Ca/Cl,F–impurity, where impurities are Ti, V, Cr and/or Fe oxides. By “face effect” is meant a difference in chemical compositions and symmetry of growth pyramids of crystallographically nonequivalent crystal faces. In the studied compounds of beryl structural type the simple crystal forms, prism and pinacoid, are characterized by hexagonal (pseudohexagonal in cordierite) and rhombic symmetry of face patterns. Degrees and characters of distinction of growth pyramids of prism and pinacoid faces of beryls, beryllian indialites, cordierites and their varieties vary in a wide range depending on the accumulation of species-forming and impurity elements. Most likely, this effect appears when crystallographically nonequivalent faces entrap chemically different “building units” (clusters spontaneously formed in a feeding medium and composed of fragments of beryl-type structure). It is supposed that the final isomorphous substitution of an impurity for the species-forming element occurs immediately on the face and/or attached unit. The character, direction, and degree of isomorphism depend on the initial composition of the medium, type of the main compound to be formed, and the presence of synchronous impurity phases. The same ratio of Si and Al concentrations in building units of the prism-pinacoid couple of cordierite with and without Ti and V suggests the persistent action of the patterns of these faces on the medium in the range of sampled concentrations of impurities and rates of growth. The contrasting face effect with respect to Si and Al in an indialite-cordierite individual is due to a drastic dissymmetry of the latter. The Ti- or V-related effects of cordierite faces are negligible. The study of beryllian indialite and its varieties showed that in some cases changes in Si-Al-Mg composition of units feeding faces with different crystallographic patterns are quite the same, with the considerable evolution of the total composition of the crystal-forming medium. As to the face effects of beryllian indialites (chiefly, with respect to Ti, V, Cr, and Fe impurities), they are owing to a considerable difference in degree of isomorphism with the participation of these elements in the building units that feed pinacoid and prism faces. Beryls demonstrate drastically contrasting face effects with respect to Ti (up to 0.20 f.u.) and in the presence of impurities, to Al (up to 0.21 f.u.); distinct effects were related to Cr (0.06 f.u.), in all varieties to Mg (up to 0.10 f.u.), and quite rarely, to Fe (0.01 f.u.), which is seen from comparison of the schemes of isomorphism implemented in prism and pinacoid. The effects under consideration and their evolution in the process of development of individuals are also clearly recognized from crystallochemical formulas of the building units feeding faces with different crystallographical patterns. By the example of beryl, it has been shown that the face effect inversion with respect to a component during the crystal growth indicates the inversion of the degree of isomorphous substitution of this element in the process of evolution of the individual (because of a drastic change in phase formation in the system) rather than the absence of relationship between face pattern and effect. Thus, in the system beryl–Mg,Ca/F,Cl–TiO2 the inversion of Mg-related effect (resulting from inversion of degrees of substitution Al3+ → Mg2+) is linked to a drastic increase in rutile amount (TiO2) crystallized together with beryl at a certain stage of solution cooling. 相似文献
9.
作为战略性矿产资源之一,高纯石英已广泛应用于集成电路、半导体芯片、太阳能等高新技术产业中,但是能够生产高纯石英的原料矿床极为稀缺,我国尤为紧缺高纯石英原料矿。鄂东南地区是湖北省脉石英矿床的主要分布区。本文针对鄂东南付家山脉石英矿床,通过光学显微镜、扫描电子显微镜观察了脉石英的脉石矿物类型和包裹体特征,采用电感耦合等离子发射光谱法(ICP-OES)对原矿进行了微量元素分析,旨在获得付家山脉石英矿床的杂质元素特征,进而评价矿床用作高纯石英原料的潜力。结果表明,付家山脉石英矿石SiO2含量大于99.95%,杂质元素主要为Al、K、Fe、Ti、Ca等,脉石矿物主要有白云母、钾长石、铁氧化物等,流体包裹体较为发育。杂质元素分析结果表明,付家山脉石英原矿质量达到低端高纯石英标准,经传统工艺提纯后,可能具有生产中高端高纯石英的潜力。 相似文献
10.
南秦岭安康地区志留系梅子垭组千枚岩中赋存丰富的脉石英矿产资源, 但其作为高纯石英原料研究程度低, 尤其是对其中影响石英提纯的痕量杂质元素含量及其赋存状态缺乏系统认识, 很大程度制约了该区高纯石英原料的质量评价和进一步的找矿突破。本文在厘定安康地区脉石英地质发育特征的基础上, 对研究区产出的3件脉状石英样品(AK200、AK201、AK202)开展了样品杂质元素检测, 对样品矿物学特征、杂质赋存形式和可提纯性能进行了研究, 进而进行了提纯实验, 结果显示, 3件样品提纯后SiO2含量分别为99.993 11%、99.997 66%和99.998 58%, 均达到高纯石英产品质量要求, 其中AK202样品提纯后达到4N8级。研究表明, 提纯后Al、Ti、Na、K为主要杂质元素, Al可能以杂质矿物、晶格杂质两种方式存在; Ti可能多以晶格杂质的方式存在; Na、K多以流体包裹体的方式存在; 杂质矿物、流体包裹体、晶格杂质对该区脉石英质量均产生不同程度影响, 其中流体包裹体为主要影响因素, 晶格杂质次之, 杂质矿物影响最小。这一结论对于评价该区的脉石英矿产资源质量、明确今后找矿目标体特征具有重要参考意义。 相似文献
11.
石英与金矿床关系十分密切,石英中含有众多的信息.通过对它的研究,可提取出许多找金矿的信息或标志.石英热发光曲线反映金的矿化强度,矿体中的石英热发光曲线呈双蜂或多峰;而矿化带中则呈包含多种隐伏峰的单蜂曲线.与成矿有关的石英红外吸光度D_2、D_2/D_1可定性地评价其含金性.含金石英中的Al_2O_3、K_2O、Na_2O、H_3O~(+)的含量随着矿体埋藏深度的增大而增加,可用其判别矿体的埋藏深度. 相似文献
12.
13.
利用电子显微镜(EM)及能谱仪(EDS),分析研究了变生热液形成的载金石英的化学成分、离子扩散作用以及金在石英中的赋存状态等问题,探讨了它们的形成和变化机理。研究结果表明:Al~(3+)、Ti~(3+)、TFe、Na~(+)、K~(+)、Ca~(2+)等在石英中为类质同像混入物;石英和黄铁矿之间的离子相互扩散作用,表现为石英中Al离子的带出和Fe离子的带入,黄铁矿中Fe离子的带出和Al离子的带入;石英中呈分散状态分布的金主要为离子金,它们充填在石英结构中,起平衡电价的作用。 相似文献
14.
云南富乐铅锌矿床黄铁矿微量(稀散)元素组成及成因信息:LA-ICPMS研究 总被引：2，自引：2，他引：0
川滇黔铅锌矿集区是华南大面积低温成矿域的重要组成部分,区内铅锌矿床是否属于MVT型矿床长期存在争议。该区铅锌矿床以富集Ge等稀散元素为特征,闪锌矿是其主要载体矿物,但稀散元素在黄铁矿中是否富集、赋存状态及微量元素组成特征等研究基本属于空白。本文通过LA-ICPMS研究富乐黄铁矿中微量元素(尤其是稀散元素)的富集特征,发现黄铁矿中也相对富集Ge。本研究样品选自富乐矿床的富乐和富盛两个矿段,包括1350、1410和1536三个中段(由深到浅),LAICPMS分析结果表明,该矿床黄铁矿以富集Cu、As、Co、Ni为特征,局部富集Pb(Sb)和Zn(以方铅矿和闪锌矿显微包裹体形式赋存于黄铁矿中),该类黄铁矿富集的稀散元素主要为Se、Ge及少量Tl、Te,而Cd和In以类质同象形式赋存于含Zn的显微包裹体(闪锌矿)中,类质同象是其余稀散元素主要赋存形式,且黄铁矿中Ge与Cu存在较好相关关系,可能存在Cu~(2+)+Ge~(2+)?2Fe~(2+)耦合置换方式。此外,黄铁矿中稀散元素的富集与成矿元素(特别是Cu)的富集密切相关,随着成矿作用的进行,从矿体深部到浅部,成矿温度逐渐降低,Se/Te比值逐渐升高,且稀散元素与成矿元素呈逐渐增加趋势。研究表明,该矿床黄铁矿的Co/Ni比值基本都小于1. 00,暗示其属于沉积改造型黄铁矿,在Co-Ni和稀散元素Se-Tl含量投影图上,富乐矿床黄铁矿的投影点与MVT型矿床投影区基本一致,而明显有别于SEDEX、VMS和矽卡岩型矿床中黄铁矿的投影区,结合富乐矿床类似于MVT型的地质特征,我们认为富乐矿床属于MVT型铅锌矿床。 相似文献
15.
湖南锡矿山锑矿床中石英是与矿化作用密切相关的硅化作用的产物。通过野外地质调查和室内矿物学研究表明石英可分为 3个世代 :Ⅰ世代石英产于由交代作用形成的早期硅化岩中 ,Ⅱ、Ⅲ世代石英产于由充填作用形成的矿体中。石英的微量元素成分分析、红外吸收光谱、包裹体红外相对光密度、稀土元素含量比值揭示了成矿溶液的某些重要信息 ;石英的晶胞参数与其类质同象元素Al、Ti、Na的含量呈正相关关系 ;主矿化阶段形成的Ⅱ世代石英的发光强度随矿化强度呈现明显的变化规律 ,可以作为矿区石英的找矿标型特征。石英的稀土元素配分模式显示热液中的硅质很可能来源于壳源花岗岩浆。该研究成果对分析锑矿床的形成过程及机制和找矿具有十分重要的意义。 相似文献
16.
石英的微量元素记录了石英生长的物理化学条件。通过微量元素对石英原岩进行分类的研究历史已久,经典工作是在以微量元素为坐标轴的图解上绘制各类型石英的分布范围,以区分石英类型。经典图解包括Rusk(2012)提出用于区分三种矿床类型石英的Al-Ti二元图解,和Schr9n et al.(1988)提出的用于判别不同岩浆岩类型石英的Ti-Al-Ge三元图解。越来越多的研究表明,上述图解不能满足对更多石英类型进行分类的需求,同时也出现与部分已知产状类型的石英微量元素判别相矛盾的情况。随着石英原位微区测试方法的成熟,高精度石英微量元素数据逐渐丰富为系统开展机器学习提供了大数据基础,为石英微量元素研究提供了新的角度和可能性。本研究运用机器学习分类方法对石英微量元素进行精确数学分析,提出Ti/Ge-P图解为石英成因研究提出新的地球化学指标。本文同时测试了六种经典机器学习分类算法,提高Ti/Ge-P图解在石英成因分类研究上的精度。此Ti/Ge-P图解适用于多种矿床研究,包括但不局限于斑岩型矿床、矽卡岩型矿床、浅成低温热液型矿床、卡林型矿床以及造山型矿床中的石英。这项工作是大数据技术与机器学习技术在地球化学研究中的积极探索。 相似文献
17.
The effect of the formation conditions of pegmatites in the Mama-Chuya mica belt on the distribution of isomorphic Al, Ti, and Ge impurities in quartz detected by electron paramagnetic resonance (EPR) has been estimated using the isogen method, which takes into account the relationship between this distribution and geological time. It has been revealed that each of the studied types of pegmatite veins is described by special isogens that reflect interrelations between concentrations of various isomorphic impurities. The typification of veins, enrichment of parental melt in water, and other factors affect the isogens. New potentialities of the isogen method for genetic analysis of quartz have been established. 相似文献
18.
The Central Aldan ore district (CAOD) is considered as an integral ore-forming magmatogenic system (IOMS) consisting of ore-forming
systems of different ranks. The epicenter of the IOMS is occupied by the main (head) magma conduit expressed at the present
erosion level as the Western El’kon magmatic area. The systematic radial position of the main ore-bearing zones relative to
the IOMS’s epicenter is considered as an indication of their relation to the head magma conduit. There are daughter ore forming
systems of the first order (the El’kon (EOS), Kuranakh (KOS), and Tommot (TOS)), as well as ore systems of higher orders.
Ore zoning distinctly observed in the EOS and KOS and outlined in the TOS consists of the change of the gold or molybdenum
(EOS) mineralization for gold-uranium mineralization toward the head of the magma conduit. The ore objects are derivatives
of magmatic reservoirs (chambers) located at different levels of the staged magmatogenic system. The gold and uranium mineralization
is mainly related to the pervasive potassic metasomatism. The CAOD is considered as a superproductive area promising for revealing
new large ore deposits and recommended as a priority object for large scale gold and uranium exploration. 相似文献
19.
昆嵛山花岗岩是牟平—乳山金矿成矿带的围岩，在其成因和定位时代上长期存在争议。本文对岩体地质和地球化学特征进行了系统研究，并就岩体成因及其与金矿的关系进行了讨论。作者认为，昆嵛山花岗岩是在中生代由岩浆缓慢冷凝结晶形成的大型复式岩基，并非交代成因。它由垛崮顶片麻状花岗闪长岩（１４７Ｍａ）、八门邹家斑状花岗闪长岩（１３５Ｍａ）、瓦善—水道弱片麻状二长花岗岩及五爪山片麻状含榴二长花岗岩（１２０Ｍａ）组成，成分具贫铝富碱的特点。岩浆来源于中下地壳中酸性变质火山岩系部分熔融形成的岩浆，其形成温度为６５０—７５０℃。岩体经历了韧性和脆性变形作用，不同方向的片麻状构造是岩浆结晶期韧性变形作用的结果。脆性变形形成的断裂和破碎带是本区主要的导矿和容矿构造。花岗岩定位、韧和脆性变形作用与金矿成矿作用有十分密切的关系 相似文献