我国夕卡岩矿床中的辉石和似辉石特征及其与金属矿化的关系

根据我国３７个夕卡岩矿床中辉石和似辉石的成分和共生矿物特征等的综合研究分析，指出不同金属矿化夕卡岩中的辉石、似辉石类型和成分特征各不相同，因而作为鉴别夕卡岩含矿性的翻来覆去矿的地球化学标志，岩浆期镁夕卡岩中的辉石为铝透辉石，可伴生磁铁矿化；岩浆期后镁夕卡岩中的为较纯的透辉石，可能伴生Ｆｅ、Ｃｕ、Ｍｏ、Ｓｎ、Ａｕ等矿化；钙夕卡岩中的辉石主要为透辉石，而似辉石成分多为硅灰石，随着辉石中钙铁辉石和钙鳃辉     

矽卡岩矿床共生单科辉石—石榴石氧逸度计及主要金属矿化类型矽岩生成的氧逸度条件

基于我国主要类型矽卡岩矿床的研究，结合Ca-Fe-Si-C-O体系的实验成果，以共 生矿物固溶体热力学分析为手段，建立了共生单斜辉石一石榴石氧逸度计。对我国主要类型矽卡 岩的研究表明:不同金属矿化及不同产出条件的矽卡岩形成于不同的氧逸度环境，具有不同的氧 逸度变化趋势和温度一氧逸度效应。共生单斜辉石一石榴石矿物对是形成介质的良好氧逸度计、酸度计。它有助于判别矽卡岩的金属矿化类型。     

中国矽卡岩矿床找矿新进展和时空分布规律

近年来,中国矽卡岩矿床找矿取得了很大的新进展:西藏冈底斯成矿带和班公湖-怒江成矿带发现和探明了十余个大中型矽卡岩铜、金多金属矿床;在青海西部祁漫塔格成矿带发现和探明了不少铁多金属矽卡岩矿床;在东部地区发现和探明了一批大型隐伏的矽卡岩矿床,如河北白涧铁矿床、江西朱溪钨多金属矿床、湖南锡田锡钨矿床、福建上房钨矿床等。在新疆西天山发现和探明了一批大(中)型与火山-侵入活动有关的矽卡岩铁矿床。另外,在新疆发现白干湖、沙沟等大型钨矿床,在甘肃也发现和探明了大型钨矿床。学者们对上述矿床进行了较详细的研究。中国主要矽卡岩矿床最新同位素测年资料表明,矽卡岩矿床的生成时代从元古宙、古生代、中生代到新生代都有,但最重要的成岩成矿期是中生代的燕山期。在空间分布上,赵一鸣等(1990)曾划分出14个重要的矽卡岩成矿带,通过广大地质工作者的努力,在西藏、新疆和青海等省(区)找矿工作的重大进展,又新增4个矽卡岩成矿带,即西藏冈底斯成矿带、班公湖-怒江成矿带、青海祁漫塔格成矿带和新疆西天山成矿带。     

湖北铜绿山铜铁矿床成矿机制探讨

以铜绿山铜铁矿为例,探讨了浅成岩体冷却过程中夕卡岩及夕卡岩矿床在接触带上的形成过程及其耦合条件。在铜绿山矿区,矿体主要产出于石英二长闪长玢岩与下三叠统大冶群碳酸盐岩的半岛状 岛链状残留、捕虏体接触带中,矿体与夕卡岩密切共生。此次工作根据大量野外观察,结合对已有资料综合研究,提出成矿空间为冷缩低压区的概念,即夕卡岩及夕卡岩矿床形成的起因是在岩浆固结后的岩石冷凝收缩过程中,在接触带上形成了一个能使流体持续汇聚和长期驻留的低压区--冷缩低压区系统。这个系统与岩浆期后热液的耦合,在超临界流体、CO2气体和临界转换作用的配合下,满足了夕卡岩型矿床成矿的需求,形成了铜绿山矿床。     

关于层控式矽卡岩型矿床——以安徽省内下扬子坳陷中一些矿床为例

矽卡岩型矿床是矿床学上的一个重要成因类型。它在我国(特别是东部成矿域)已知矿产资源中占有突出的地位,在成矿作用和富集规律的研究方面也获得了许多有意义的成果,构成我国矿床理论和实践上的一大特色。根据矽卡岩型矿床的成矿控制因素,矿体与岩体和容矿岩层的关系,可把这类矿床归纳为几个“式”:(1)接触式(矿体就位于岩体接触带包括捕虏体接触带上);(2)层控式(矿体沿一定层位在外接触带作单层或多层产出);(3)裂隙充填式(脉状含矿矽卡岩沿裂隙充     

论中国斑岩、矽卡岩型铜、钼矿床的形成与地壳演化的关系

根据中国120个斑岩、矽卡岩型铜、钼矿床的研究表明:中国斑岩、矽卡岩钢、钼矿床形成于地壳发展的一定阶段,一定构造单元。即形成于吕梁期之后的地槽褶皱区和印支期之后的地洼区,特别是后者,它是中国斑岩、矽卡岩铜、钼矿床发育最盛时期。它们分别占中国该类铜、钼矿床总量的84.7％,96.6％斑岩、矽卡岩铜、钼矿床的形成主要是由于地洼或地槽褶皱时期构造、岩浆活动改造或活化、迁移、富集原地层中的成矿物质或矿源层、层状铜(钼)矿的结果。     

Geology of gold-bearing skarn deposits in the middle and lower Yangtze River Valley and adjacent regions

The middle and lower Yangtze River Valley and adjacent regions are the most important metallogenic belt of gold (and copper)-bearing skarn deposits in China. The total gold reserves in this belt have been estimated at more than 600 t. The gold-bearing skarns are mainly distributed in the southeastern Hubei, Tongling and northern Anhui regions. Favorable tectonic settings are depressions and fold zones of the platforms, i.e., mobile belts. These skarns are hosted by platformal limestone, dolomitic limestone and dolomite of the Triassic, Carboniferous-Permian and Middle to Lower Cambrian formations. The related intrusions are Yenshanian (180 to 113 Ma) calc-alkaline quartz monzodiorite, granodiorite, quartz monzonite, monzogabbro, and their hybabyssal facies. The intrusions have high Fe₂O₃/FeO (>0.5) and intermediate initial ⁸⁷Sr/⁸⁶Sr ratios (0.7046 to 0.7087). Their REE distribution patterns are LREE-enriched and exhibit smooth, right-dipping curves. These suggest that the source materials mainly came from upper mantle, with contamination by sialic crustal components. The auriferous skarns are both calcic and magnesian, but calcic skarns are most common. The constituent minerals of the calcic skarns are diopside, garnet, wollastonite, vesuvianite and scapolite, whereas magnesian skarns are dominated by forsterite, spinel, diopside, phlogopite, chondrodite and clinohumite, with abundant superimposed serpentine, clinochlore and brucite. The compositions of coexisting pyroxenes and garnets are diopside and andradite, indicating the high oxygen fugacity and low acidity conditions. Gold is closely associated with Cu (Pb, Zn) sulfides and exists mainly in the form of native gold and electrum. Arsenides, tellurides, bismuthides and selenides are present in many ore deposits. Therefore, Cu, As, Bi, Te, Ag, Pb, Zn, Se and Co are the major metals present in the deposits and are important geochemical ore-searching indicators. In some Au (Fe, Cu) magnesian skarns, magnesiomagnetite, magnesioferrite and ludwigite are locally abundant. The metasomatic zoning in many gold skarn deposits is very distinct consisting of an outward sequence of: Fe (Cu)→Cu (Mo)→Cu (Au)→Au (Cu)→Au (Pb, Zn). The geologic characteristics of Au (Cu) skarn deposits that formed in the mobile platformal setting of China have distinct differences compared to Au skarns formed in orogenic belts at convergent plate margins in British Columbia and the western USA.     

Application of the sphalerite geobarometer to some skarn-type ore deposits

Based on the equation recently determined, formation pressures of skarn-type ore deposits were estimated from the composition of sphalerite coexisting with pyrite and hexagonal pyrrhotite. As criteria for equilibrium among sphalerite, pyrite and hexagonal pyrrhotite, the following three points were carefully checked on each specimen: 1) the presence of hexagonal pyrrhotite, 2) no time sequences among the formation of sulfide minerals, and 3) no compositional variation in sphalerite. Most of the Cu-Fe skarn deposits studied were formed under pressures of more than 1 kb, whereas Zn-Pb(-Cu-Fe) deposits tend to have formed at relatively shallow environments, namely under less than 1 kb. The calculated pressures are qualitatively consistent with the depth of formation of deposits estimated from the geological evidences. The sphalerite geobarometry is quite sensitive even at low pressure ranges, and it is applicable to the deposits formed under shallow conditions.     

Zircon U–Pb geochronological,trace element,and Hf isotopic constraints on the genesis of the Fe and Cu skarn deposits in the Qiman Tagh area,Qinghai Province,Eastern Kunlun Orogen,China

Fe and Cu skarn deposits are very important skarn types worldwide, but it is currently unclear whether the nature of intrusions related to Fe and Cu skarn deposits exerts a key influence on variations in metal associations between Fe and Cu skarn deposits. The Qiman Tagh area of Qinghai Province (QTQP), located in the Eastern Kunlun Orogen (EKO), provides a good opportunity to address this issue. Here, integrating new zircon U–Pb ages, trace elements and Hf isotopes from this study with published data, we constrain the sources of magma associated with Fe and Cu skarn deposits within the QTQP and discuss their role in controlling differences between Fe and Cu skarn deposits.Combined with published data, two discrete suites of the intrusions associated Fe and Cu skarn deposits have been recognized in the QTQP: (1) 245.1 ± 1.5 Ma granodiorite (related to a 245.5 ± 1.6 Ma Cu skarn deposit) has zircon εHf(t) values of −11.9 to −2.1; (2) 235–224 Ma monzonites, quartz monzonites, granodiorite porphyries, monzogranites, and granites associated with 234–225 Ma Fe skarn deposits are characterized by relatively high zircon εHf(t) values (−5.1 to +5.9). The Sr–Nd–Hf isotopic data suggest that the intrusions of Suite 1 and 2 were dominantly derived by partial melting of a Mesoproterozoic juvenile mafic lower crust. Suite 2 intrusions associated with Fe skarn deposits have more mantle components in their magma sources than rocks of Suite 1 that are related to a Cu skarn deposit. Furthermore, zircon εHf(t) values of intrusions associated with Fe and Cu skarn deposits in the QTQP show a negative correlation between mantle components in the magma sources and the contents of Cu and Zn in these deposits. Zircon trace elements indicate that the intrusions associated with Fe skarn deposits are relatively less oxidized than the rock associated with Cu skarn deposit in the QTQP, reflecting a positive correlation between crustal components in the magma sources and oxygen fugacity of the magmas. This indicates that different proportions of mantle and crustal materials in the magma sources may affect oxygen fugacity and Fe contents of the magmas, which possibly leads to the variations in metal associations between Fe and Cu skarn deposits in the QTQP. Zircon U–Pb ages, trace elements and Hf isotopic compositions, combined with geological, geochronological, and geochemical evidence, indicates that having different proportions of mantle components in the magma sources of intrusions associated with Fe and Cu skarn deposits is one of the most critical factors controlling differences in metal association between Fe and Cu skarn deposits.     

广西富钟贺地区钨锡多金属矿床成矿系列研究

富钟贺地区位于湘桂褶皱系湘中南褶皱带与华夏褶皱带的交汇处,区内良好的成矿条件形成了各种不同类型的钨锡多金属矿床.钨、锡多金属矿床主要赋存于泥盆纪地层中,在空间上从花岗岩内部的云英岩型—矽卡岩矿床→内外接触带的矽卡岩型钨锡矿床→外接触带或远离接触带的锡多金属硫化物型和钨锡石英脉型矿床;成矿时代主要是在燕山中、晚期,成因上...     

矽卡岩岩浆对中国北方某些矽卡岩型矿床形成的制约——来自包裹体激光拉曼分析证据

本文将报道中国北方主要矽卡岩型矿床矿物熔融包裹体和流体-熔融包裹体的激光拉曼分析结果。研究目的是确认这些矿化矽卡岩矿物是否含熔融包裹体和流体-熔融包裹体,获取有关它们相态特征和相组成以及它们的分布状况(是局部的、偶然性的,还是广泛的)的信息。文章对邯邢铁矿、蒙库铁矿和杨家杖子钼矿等9个矿床12块标本中石榴石、辉石和方解石或白云石中23个包裹体进行了共聚焦激光拉曼光谱仪分析。拉曼分析结果表明,所研究的矽卡岩矿物均含熔融包裹体和/或流体-熔融包裹体,它们是岩浆矽卡岩的直接证据。结合本文激光拉曼分析结果、地质背景和其他地区岩浆矽卡岩矿物包裹体测温学研究,对所研究矽卡岩的形成机制和岩浆矽卡岩对中国北方某些矽卡岩型矿床的制约进行了讨论。认为含有熔融包裹体和/或流体-熔融包裹体的矿化矽卡岩系岩浆成因,其分布范围广泛,规模不小。中国北方某些矽卡岩型矿床的时空分布和规模受控于该地区分布的岩浆矽卡岩。希望本文有助于拓宽矽卡岩型矿床成矿规律研究和深部找矿勘探的思路。     

Rare Earth Elements as an Indicator to Origins of Skarn Deposits: Examples of the Kamioka Zn-Pb and Yoshiwara-Sannotake Cu(–Fe) Deposits in Japan

Abstract: Systematic data of rare earth elements (REEs) are presented in order to put some constraints on the origin of hydrothermal fluids responsible for two contrastive skarn deposits in Japan; the Kamioka Zn-Pb and Yoshiwara-Sannotake Cu(-Fe) deposits. Carbon and oxygen isotopic studies have demonstrated that the hydrothermal fluids responsible for the Kamioka Zn-Pb deposits are of meteoric water origin whereas those for the Yoshiwara-Sannotake Cu(-Fe) deposits are of magmatic water origin. The REE abundances of epidote skarn derived from aluminous rocks, garnet and clinopyroxene in calcic exoskarn derived from limestone, and interstitial calcite associated with sulfide minerals were determined for these contrastive skarn deposits by inductively-coupled plasma mass spectrometry (ICP-MS). A significant difference in the REE concentrations is not found between epidote skarn and aluminous original rock (plagioclase-clinopyroxene rock, called Inishi rock) from the Kamioka Zn-Pb deposits, indicating that the REEs are generally immobile during the formation of epidote skarn, and that the REE concentrations of the hydrothermal fluid are considerably low relative to the aluminous original rock. In contrast, the epidote skarn exhibits enrichment of Eu with increasing total REE concentrations relative to the aluminous original rock (quartz diorite) in the Yoshiwara-Sannotake Cu(-Fe) deposits, implying a contribution of magmatic fluid derived from granitoids during the skarn formation. Limestone generally has much lower REE concentrations related to surrounding aluminous rocks, and thus the REE concentrations of garnet and clinopyroxene in calcic exoskarn, originated from limestone, are variable due to the interaction with the hydrothermal fluids. The chondrite-normalized REE patterns of garnet, clinopyroxene, and interstitial calcite exactly provide useful information on origins of hydrothermal fluids. The REE patterns of these minerals from the Kamioka Zn-Pb deposits show lower (Pr/Yb)cn ratios, and negative Ce and Eu anomalies inherited from limestone with the decrease of This suggests that the hydrothermal fluids responsible for the Kamioka Zn-Pb deposits were depleted in REEs, and were not magmatic water in origin, but presumably meteoric one. In striking contrast, the REE patterns of exoskarn minerals and calcite from the Yoshiwara-Sannotake Cu(-Fe) deposits exhibit a positive Eu anomaly, and high (Pr/Yb)cn ratios with the considerable increase of σREE and the disappearance of negative Ce anomaly, implying that the fluids were dominantly of magmatic origin. The REE indices are very likely to be an excellent indicator to origins of the skarn deposits.     

云南镇康地区铅锌多金属矿成矿规律

镇康地区位于西南"三江"成矿带南段,是云南省重要的铅锌铁铜多金属矿矿集区之一。区内以铅锌矿为主,次为铁、锡,伴生铜、银;已发现超大型铅锌矿1个,中型铅锌矿3个,小型锡矿1个。文章认为区内的寒武系沙河厂组、核桃坪组及保山组碳酸盐岩地层和奥陶系是本区重要的赋矿层位,铅锌多金属矿床受构造控制明显,多分布在区域褶皱核部断裂带上,往往与夕卡岩型铁矿及夕卡岩体相伴,且产于花岗岩体与围岩接触带上。因此,区内的磁异常及区域低重力场中的次级重力高异常是寻找铅锌多金属矿的主要标志,而铅、锌、铜、银等元素的化探异常及重砂异常范围可指示铅锌矿的存在区域。     

我国含银夕卡岩矿床的分布和地质特征

含银夕卡岩矿床在我国银矿床中占有重要位置,它们主要分布于南岭、长江中下游、华北地台北缘和东南沿海等一些重要褶皱带中,其控矿地层较多,其中以石炭－二叠系最重要。与成矿有关的岩浆岩为燕山期壳源重熔型中酸性和酸性浅成侵入岩,次为华力西期和印支期。Ag(Pb,Zn)矿化与猛质夕卡岩紧密伴生,往往产于离岩体接触带有一定距离的碳酸盐围岩中,并常与含Fe,Cu,Au,W,Sn钙（镁）夕卡岩构成明显的交代矿化分带,成为重要的找矿标志。     

夕卡岩矿床研究的某些重要新进展

夕卡岩矿床是一种具有重要工业意义的矿床类型，是世界上富铁矿，钨、锡、铋、铅锌，金和金云母，透辉石，硅灰石等金属和非金属矿产的重要来源。这类矿床不仅分布广泛，矿物组合特殊，而且包含有内生成矿作用许多复杂的成因信息。因此，一个多世纪以来国际上对夕卡岩矿床的研究长盛不衰，不断有所创新，文章回顾了近二十年来，在成矿的构造背景，矿床的多成因性，岩浆期和岩浆夕卡岩，碱交代与成矿，交代分带，含银铅锌锰质夕卡岩，含金夕卡岩和夕卡岩含矿性评价标志等方面新的研究进展。     

滇西保山核桃坪铅锌矿床稀土元素地球化学特征及其成因意义

核桃坪铅锌矿床产于滇西保山古生代地块内,是近年来在西南“三江”地区勘查发现的大型铅锌(铜银)多金属矿床,也是该区为数不多的以断控脉状矽卡岩赋矿为特征的矿床。详细研究了区内铅锌矿体的各种赋矿围岩、蚀变(脉)体及矿石的稀土元素地球化学特征,结果表明：围岩的稀土元素主要富集在粘土矿物中,上侵的矽卡岩流体萃取了围岩中的稀土元素,并使自身稀土元素组成发生改变;当前揭露浅部矽卡岩的成岩流体为中-低温、酸-弱酸性流体,其酸度随流体演化而不断增加。认为核桃坪铅锌矿床可能是一个远端矽卡岩型矿床,矽卡岩及伴生铅锌(铜银)的成岩成矿作用均受控制于隐伏的岩浆-热液系统。     

矽卡岩型铁矿的铁质来源与迁移富集机理探讨

矽卡岩型铁矿是我国最重要的富铁矿类型,其铁质来源及迁移富集机理是目前最核心、也最具争议的问题之一。本文在矽卡岩矿床复杂性和多成因性研究的基础上,对浅部铁质活化、迁移和富集机理进行整理归纳,建立了流程图;分别探讨了不同类矽卡岩型铁矿铁质的最大可能来源,认为与中酸性侵入体有关的该类铁矿,铁质主要源于浅部侵入岩;与酸性侵入体有关的该类铁矿,矿床附近的原始赋铁层位可能提供了大量铁质。但并非所有与酸性岩有关的此类铁床附近都存在赋铁地层,故本文对铁质深部来源的可能性进行了探讨,结合"岩浆矽卡岩-富碱侵入岩对"的概念,提出了全新的深部铁质活化、运移和富集的可能模式,即深部岩浆同化钙质岩石融离出的富铁矿浆上升并运移到浅部侵入岩与碳酸盐岩的接触带附近,与该系统中的热液相遇并反应,热液吸收矿浆中的铁质生成富铁的复合热液,后复合热液在接触带因物理化学条件的剧变而沉淀成矿。     

江西永平铜矿矽卡岩矿物特征及其地质意义

永平铜矿含矿岩石主要为绿帘石透辉石石榴石矽卡岩,这种岩石类型是与斑岩体有关的矽卡岩铜矿的典型赋矿岩石。通过对这一主要赋矿矽卡岩的研究,我们发现石榴石生长分为两个阶段:(1)早期石榴石:主要分布在石榴石颗粒核部,XAdr=1.0,主要以钙铁榴石为主,说明早期流体中可能含有较多的铁,是在较氧化条件下形成的;(2)晚期石榴石,沿石榴石裂隙重新成核或者在靠近流体通道的早期石榴石表面生长,出现震荡环带,XAdr=0.46~0.99,为钙铁-钙铝石榴石系列。石榴石发生变化的期间也形成新的矿物,如绿帘石、萤石、方解石和石英等。共存石榴石和绿帘石矿物中存在Fe3+-Al3+之间的替代,说明流体的氧逸度、组分浓度或aFe3+/aAl3+可能发生了变化。金属矿物也可能是在这一阶段形成的。永平铜矿矽卡岩从接触带到大理岩空间上有分带现象。从岩体到围岩的变化趋势为:石榴石含量减少,颜色存在红棕色-棕色-棕绿色-黄绿色-浅黄色的变化趋势;矿石品位降低,这与石榴石中Al2O3含量的变化较一致。我们认为这种变化是含矿热液对早期矽卡岩进行再交代改造的结果,表现为石榴石和绿帘石中Fe3+-Al3+含量的变化,并将Cu等金属沉淀下来。根据矽卡岩矿物的这些特征,在矿床勘探时,可依据棕色石榴石来追踪主矿体的位置。     

Compositional characteristics of garnets and pyroxenes in contact-metasomatic skarn deposits and their relationship with metallization

The compositions of more than 300 granets and pyroxenes from 14 contact-metasomatic calcic skarn deposits and calcic-magnesia skarn skarn deposits in China have been examined using electron microprobe technique. The compositions of garnets and pyroxenes from a wide variety of ore types represent ten major classes of calcic skarn deposits (Fe, Fe-Cu, Pb-Zn,W, Sn, Sn-Mo-Bi-W, W-Bi-Cu-Mo, Cu-Zn and W-Zn-Cu) and three major classes of calcic-magnesia skarn deposits (Fe-Cu, Mo, Pb-Zn). Garnets and pyroxenes show a wide range of variation in composition, but the majority of garnets are grossular-andradite solid solutions containing less than 15 mol% (spessartine + almandine + pyrope), whereas most pyroxenes are diopside-hedenbergite solid solutions containing less than 5 mol% johannesenile. Some pyroxenes from a Pb-Zn calcic-magnesia skarn deposit display an increase in Mn content. Only Sn-W calcic skarn deposits and Pb-Zn calcic-magnesia skarn deposits contain garnets with more than 15 mol% (spessartine + almandine + pyrope). Some relationships have been established between the compositions of garnets and pyroxenes and the metallization types of economically important metals in skarn deposits.     

中国碲矿成矿规律概要

富金斑岩-矽卡岩矿床产出了大部分碲资源,其他类型碲矿资源时空分布规律暂未明确。在全国矿产资源潜力动态评价项目开展过程中,本文对中国碲矿资源特征、碲矿类型、时空分布进行分析与归纳,初步总结了中国碲矿成矿规律。本文对中国碲矿的资源特征进行了介绍;收集了全国45个含碲矿床的资料,将中国碲矿分为碱性-偏碱性侵入岩型、卡林-类卡林型、浅成低温热液型、斑岩-矽卡岩型、造山型、铜镍硫化物型6大预测类型;将碲矿形成时代分为元古宙、古生代、中生代、新生代4个成矿期,划分了9个碲成矿带,即吉黑、华北陆块西缘、华北陆块北缘、辽东、秦岭、苏鲁、长江中下游、三江、南岭成矿带;厘定出34个与碲矿有关的成矿系列,建立了中国碲矿成矿谱系。综合研究所得,中国碲矿以晚古生代和中生代华北和东北地区的浅成低温热液型、斑岩-矽卡岩型、铜镍硫化物型矿床,小秦岭-熊耳山地区的造山型矿床,长江中下游和滇川黔地区的斑岩-矽卡岩型、铜镍硫化物型矿床为主。