新疆包古图地区金矿床矿化类型和与围岩关系研究

西准噶尔包古图地区是新疆北部重要的金铜产地,已发现中型金矿床1处,金矿点20余处,大型斑岩铜（金、钼）矿床1处。金矿床按矿化类型可分为石英脉-蚀变岩型、蚀变岩型、辉锑矿-石英脉型、富硫化物型以及产于斑岩型铜矿中的伴生金。石英脉-蚀变岩型是最主要的矿石类型,构成包古图地区最主要的经济矿体。蚀变岩型是包古图地区近年来发现的新矿化类型,矿体由就位于NW向断裂中的蚀变凝灰质细砂岩和蚀变凝灰岩组成。辉锑矿-石英脉型矿石中含自然砷、自然锑、Paakkonenite、方锑金矿和硫锑金银矿等罕见矿物,这些矿物都与金矿化直接相关。富硫化物型矿石中,自然铋和辉铋矿与金矿化紧密相关。这些金矿化在空间上与中酸性岩体和岩体附近的岩脉关系紧密,成因上金矿化与岩体密切相关,而与岩脉关系不大。成矿元素在岩体中含量最高,其次为岩体附近的火山碎屑沉积岩,同一区域内岩脉的成矿元素含量最低,离岩体越远,成矿元素含量越低。Au与As、Sb、Bi之间具有不同程度的正相关性,As、Sb、Bi异常是该区找金的重要化探标志。中酸性岩体是最重要的找矿标志,岩体附近的断裂系统是金矿最有利的就位空间。     

新疆康古尔金矿成矿阶段及其年代学

根据矿床的地质特征，矿脉穿插关系，矿物共生组合及矿石Rb─Sr等时线，Sm─Nd等时线、40Ar／39Ar年龄谱等年代学资料，认为康古尔金矿热液成矿过程主要经历了4个成矿阶段。Ⅰ为磁铁绿泥蚀变岩成矿阶段；Ⅱ为黄铁矿石英脉成矿阶段；Ⅲ为多金属硫化物石英脉成矿阶段；Ⅳ为碳酸盐石英脉矿化阶段。矿化类型以蚀变岩型为主。     

一种重要的稀有金属矿床类型——斑岩型稀有金属矿床

近年来,随着地质工作的不断深入,斑岩型矿床(如斑岩铜矿、斑岩钨矿、斑岩钼矿、斑岩锡矿等)不断为人们所发现,其共同特点如下:1.矿化赋存在中—酸性浅成或超浅成的侵入岩体内,岩体形态多呈岩株、岩瘤、岩筒、岩脉、岩漏斗状。岩石普遍具斑状结构。2.矿石呈细脉浸染状及浸染状。矿石中     

山东招远界河金矿床矿化垂向变化特征研究

界河金矿床作为胶东地区典型的蚀变岩型金矿床,目前通过坑道工程揭露已经探明其矿体垂深达800m左右。从矿区浅部向深部,其矿化呈现出一定的规律性变化:矿化类型呈现出浅部以蚀变岩型矿化为主、深部以裂隙脉型矿化为主的分带规律;矿体规模逐渐变小,矿化强度逐渐减弱,矿体产状也逐渐变缓。此外,矿物组分、矿石组构、围岩蚀变以及微量元素特征等从浅部向深部也均呈现出规律性的变化。结合区域内石英脉型和蚀变岩型金矿化的垂向分带特征,初步建立了胶东地区金矿化在垂向上的"三段式"分带模式:浅部以石英脉型矿化为主,中部以蚀变岩型矿化为主,深部则以裂隙脉型矿化为主。     

柴北缘查查香卡铀-钍-铌-稀土矿床地质特征及矿床成因:一种与钠长岩相关的新矿化类型

青海查查香卡铀-钍-铌-稀土矿床位于柴达木盆地北缘的柴达木—阿尔金超高压变质杂岩带东端,是中国发现的首例与钠长细晶岩脉相关的铀-钍-铌-稀土多金属成矿系统。矿化主要分为两类:脉状矿化和微细浸染脉状矿化。脉状矿化即为钠长岩脉;微细浸染脉状矿化是以微细浸染细脉产于绿片岩围岩中的矿化类型。详细的矿物学工作研究表明查查香卡矿床可初步划分为岩浆、热液主成矿和成矿后3个阶段。岩浆阶段以发育"水滴状"铀-钍-铌矿物(晶质铀矿、铀钍矿、钍石、维铌钙矿等)包体为典型特征,产于最主要的造岩矿物钠长石中;热液主成矿阶段主要以稀土矿化为主,伴随铌和钍矿化作用,矿石矿物包括褐帘石、氟碳铈矿、钍石、含铌榍石(?)、锆石等,与磷灰石、方解石、绿泥石、石英等中低温脉石矿物普遍共生;成矿后阶段以广泛出现的方解石±石英网脉为特征。通过矿物学研究和主微量元素数据的综合分析,初步认为钠长岩脉为岩浆-热液成因,源于富含稀土和铌等成矿元素的富集地幔部分熔融岩浆的演化;岩浆成矿作用过程中可能经历了硅酸盐熔体与碳酸盐/磷酸盐熔/流体的分离作用,但本矿床更为重要的成矿元素富集机制为硅酸盐熔体与富氯岩浆热液流体的不混溶作用,后者引发本矿床大规模的稀土成矿作用,并活化和再富集了铌和钍。钠长岩脉特征的红色形貌特征可作为此类矿床一个重要的野外找矿特征,根据类似成矿系统的成矿模式,认为矿床深部及外围隐伏区仍有较大的成矿潜力。     

辽宁王家崴子金矿床矿石特征与金的赋存状态

王家崴子金矿主要的矿石类型为含金石英脉型.矿石中富含黄铁矿,作为主要的载金矿物,与金矿化具有密切的时空及成因联系,是金矿化的重要指示矿物.矿石呈不等粒粒状、交代溶蚀结构,块状、致密块状、细脉浸染状构造.金矿物以形态复杂的中、细粒状银金矿、金银矿为主,赋存形式有裂隙金、晶隙金、包裹体金.载金矿物有黄铁矿、方铅矿、闪锌矿、黄铜矿、石英等.综合分析认为,该矿床具有变质热液型金矿床的特点,多源性的中温-中低温热液为主要成矿因素.     

阿尔泰萨热阔布金矿床的自然铋及其与金矿化关系

萨热阔布金矿是阿尔泰山南缘金一多金属矿带中与断裂变质作用有关的石英脉一蚀变岩型金矿床。本文通过电子探针的研究,在该矿区发现较多的自然铋矿物,它与金矿化关系非常密切,产出于多金属硫化物阶段,与方铅矿、黄铜矿等共生。矿区蚀变岩和矿石的微量元素R型聚类分析表明,Bi与Au相关最密切,Au、Cu、Ag、Bi是主要的成矿元素组合。Bi异常可以作为金矿化的重要指示,自然铋矿物的出现可以作为含金石英脉富矿地段的重要标志。     

西藏甲玛铜多金属矿床金矿地质特征及成矿作用

甲玛铜多金属矿床按照赋矿岩石不同,共包含产于矽卡岩中的与铜共生的金矿(化)体、产于板岩-角岩中的脉状金矿(化)体、产于大理岩中的脉状金矿(化)体以及产于玢(斑)岩脉中的独立金矿(化)体4种金矿化类型。矽卡岩中的金矿化较强,全矿区金品位×厚度基本都大于1 m.g/t,存在多个富金块段;板岩中金矿化主要分布在矿区外围破碎细粒黄铁矿化硅化板岩中,角岩中金矿(化)体以富含雄黄、雌黄为特征;大理岩中金矿化较弱,矿(化)体通常呈透镜状产出;玢(斑)岩中金矿化主要产于岩脉中的石英脉内。矿石中金的赋存状态主要以独立矿物和类质同像形式存在。独立矿物形式的金以自然金、银金矿存在于铜矿物、石英、黄铁矿等载金矿物内;类质同像形式的金主要存在于以斑铜矿、黄铜矿为代表的铜矿物中。金矿物赋存状态以粒间金、包裹金为主,其次为连生金和裂隙金。笔者以甲玛铜多金属矿床金的地质特征、分布规律及赋存状态为研究基础,推测甲玛金成矿作用与幔源C-H-O流体有关,并初步建立了甲玛铜多金属矿床金成矿模型。此外,提出了运用模型开展区域及矿区下一步找矿工作的建议。     

湖北丹江口市陈家垭铁矿床地质特征及成矿模式探讨

陈家垭铁矿床位于东秦岭Au-Ag-Mo-Cu-Pb-Zn-Sb-非金属成矿带.含铁围岩变细碧玢岩、变角斑质凝灰岩是成矿的基础,矿化强度与离火山活动中心的远近成正比,区域变质作用是促使矿物改造,使含铁火山岩中铁矿重新组合成浸染状磁铁矿—赤铁矿,使其富集.     

桂北宝坛锡多金属成矿区平英岩体晚期侵入岩的年代学、地球化学特征及其地质意义

桂北宝坛锡多金属成矿区内岩浆活动频繁,其中与锡多金属成矿作用有关的平英岩体由早晚两期侵入岩组成,且晚期侵入岩中常含有较多的电英岩包体。岩石学、锆石U-Pb年代学和地球化学研究表明：平英岩体晚期侵入岩主要岩性是（中）细粒斑状黑云母（二长-）碱长花岗岩;晚期侵入岩的形成年龄为（769.2±2.5）Ma,而电英岩包体的形成年龄为（795.1±3.1）Ma;平英岩体总体以富含大离子亲石元素（LILE,包括Rb、Th和U等）、贫高场强元素（HFSE,包括Nb和Ti等）为特征,其早期侵入岩属于高钾钙碱性强过铝质S型花岗岩,具有明显的Th-U元素"U"型峰值以及Ti元素"V"型谷值,晚期侵入岩属于钾玄岩系列岩石,具有U元素"V"型尖峰值以及La-Nd和Eu-Ti元素"U"型谷值,二者在地球化学特征上存在较大的差异。结合岩浆源区性质的研究结果,早期侵入岩属于造山后花岗岩类,可能是源自泥质岩类部分熔融形成的岩浆,再经历高程度分离结晶作用形成的产物;而晚期侵入岩属于非造山花岗岩类,可能是源自泥质岩和砂屑岩类部分熔融形成的岩浆与幔源岩浆发生了不同程度的混合形成的产物。结合电英岩包体和寨滚锡多金属矿床中岩浆热液成矿阶段形成的电英岩脉在成因上存在亲缘关系,且其形成年龄与田棚岩体的形成年龄基本一致的特征,推测电英岩包体应为晚期侵入岩侵位过程中捕获早期侵入岩（田棚岩体）侵位过程中形成的岩浆热液型电英岩脉而形成的包体,其形成年龄可能代表了本区电英岩成矿阶段的成矿年龄。     

铁矿物催化氧化技术在水处理中的应用

广泛存在于地下水中的各种有机污染物严重影响着水资源的安全利用,常见的水处理工艺对持久性有机污染物去除效果不够理想。近年来,天然含铁矿物作为催化剂,催化过氧化氢的化学治理方法对各种有机污染物去除效果显著。概述近年来主要含铁矿物、负载型矿物和纳米矿物材料催化过氧化氢在地下水有机污染去除中的应用,探讨了该领域的发展现状和存在问题,并对其应用前景进行展望。认为天然矿物材料具有成本低、在地壳中含量高、环境友好等特点,可用于多种有机污染物的去除与降解。但处理过程中,天然有机质的作用、纳米矿物材料的毒性和地球化学归宿问题应该做进一步研究。     

铁矿物催化氧化技术在水处理中的应用

广泛存在于地下水中的各种有机污染物严重影响着水资源的安全利用,常见的水处理工艺对持久性有机污染物去除效果不够理想。近年来,天然含铁矿物作为催化剂,催化过氧化氢的化学治理方法对各种有机污染物去除效果显著。概述近年来主要含铁矿物、负载型矿物和纳米矿物材料催化过氧化氢在地下水有机污染去除中的应用,探讨了该领域的发展现状和存在问题,并对其应用前景进行展望。认为天然矿物材料具有成本低、在地壳中含量高、环境友好等特点,可用于多种有机污染物的去除与降解。但处理过程中,天然有机质的作用、纳米矿物材料的毒性和地球化学归宿问题应该做进一步研究。     

Magnetic, Geochemical and Mineralogical Charac teristics of Soils in Qiangtang Basin, Tibet, China: Implications for Prospective Oil and Gas Land

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｐｒｅｓｅｎｃｅｏｆｍａｇｎｅｔｉｃａｎｏｍａｌｉｅｓｏｖｅｒｏｉｌａｎｄｇａｓｆｉｅｌｄｓｈａｓｂｅｅｎｋｎｏｗｎｆｏｒｓｅｖｅｒａｌｄｅｃａｄｅｓ,ｂｕｔｉｔｉｓｏｎｌｙｉｎｒｅｃｅｎｔｙｅａｒｓｔｈａｔｔｈｅｐｈｅｎｏｍｅｎｏｎｈａｓｂｅｅｎｃｒｉｔｉｃａｌｌｙｉｎｖｅｓｔｉｇａｔｅｄ .Ｔｈｅｍａｇ ｎｅｔｉｃｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｓｏｉｌａｎｄｓｅｄｉｍｅｎｔａｒｅｃｌｏｓｅｌｙｒｅｌａｔｅｄｔｏｓｏｍｅｇｅｏｃｈｅｍｉｃａｌｐｒｏｃｅｓｓｅｓ,ｓ…     

与前寒武纪含铁建造有关的铁矿床基本特征及研究进展

与前寒武纪含铁建造有关的铁矿床是最具经济价值的铁矿床类型,多形成于太古代和早元古代海底的环境。含铁建造结构多呈条带状,故被认为条带状含铁建造(BIF),粒状含铁建造(GIF)较为少见。条带状含铁建造是由各种富铁矿物组成的非均一组合,矿物包括含铁的氧化物、硅酸盐、碳酸盐和硫酸盐。而粒状含铁建造则主要由含铁的氧化物和硅酸盐组成,偶而富含含铁碳酸盐。根据结构及组成的不同,含铁建造可分为两类:阿尔戈马型(Algoma type)和苏必利尔型(Superior type),其中苏必利尔型含铁建造是最为重要的成矿母岩。以其为母岩形成的矿床可分为三类:未经富集的原生含铁建造矿床,假象赤铁矿-针铁矿矿床和高品位赤铁矿矿床,其中以高品位赤铁矿矿床最为重要,其形成与成岩作用、表生作用及深部流体的参与有关。我国在下一步工作中应加强对中高品位矿床成因的研究,并对国内已有类似矿床进行再认识,进而取得找矿突破。     

Mineralogy and Mode of Occurrence of Gold, Silver and Bismuth of the Caijiaying Lead-Zine-Silver Deposit, Hebei Province

The deposit under study is a hydrothermal filling-metasomatic vein type lead-zinc-silver deposit, in whichgold and silver can be recovered as by-products. These metals mainly occur as microgranular native gold,electrum, stephanite, acanthite, pyraragyrite, freibergite, and native silver. Gold minerals tend to be associatedwith galenobismutite, native bismuth and unnamed Bi_2Te. They are either enclosed in pyrite, marmatite,iron-bearing sphalerite and galens or fill the microfissures of these minerals. Silver minerals usually occur incleavages or fissures of galena, marmatite and pyrite, but are not associated with gold and bismuth minerals.Gold and silver mineralizations occurred later than lead and zinc, while the silver mineralization was precededby that of gold.     

阿尔巴尼亚布尔齐泽壳-幔过渡带豆荚状铬铁矿成因及其对富Ti熔体交代作用的记录

豆荚状铬铁矿是关键金属铬的重要来源之一,尽管豆荚状铬铁矿的研究取得了诸多进展,但对于发育于蛇绿岩壳-幔过渡带的铬铁矿成因却涉及较少。阿尔巴尼亚布尔齐泽岩体壳-幔过渡带中产出的Cerruja豆荚状铬铁矿矿床,其矿体及纯橄岩围岩普遍被辉石岩脉穿切,辉石岩脉与矿体接触带以及辉石岩脉中的铬尖晶石强烈破碎,在铬尖晶石的裂隙和包裹体中发育大量富Ti矿物相,如金红石、钛铁矿和榍石等,是研究壳-幔过渡带铬铁矿成因的理想对象。Cerruja豆荚状铬铁矿及纯橄岩围岩中铬尖晶石Cr#分别为0.56~0.58和0.52~0.55,属于高铝型铬铁矿。接触带及辉石岩脉中的铬尖晶石Cr#明显升高（分别为0.57~0.67和0.72~0.83）,且Ti、V、Mn、Sc、Co、Zn和Ga含量也升高。本文依据铬尖晶石的结构及矿物化学成分变化特征,提出布尔齐泽壳-幔过渡带铬铁矿经历多阶段演化叠加：首先,Mirdita-Pindos洋盆在侏罗纪（约165 Ma）发生洋内初始俯冲,软流圈物质上涌生成的MORB-like弧前玄武质熔体随着俯冲的进行逐渐向玻安质熔体演变,期间产生的过渡型熔体与地幔橄榄岩反应生成高铝型铬铁矿;然后,部分MORB-like弧前玄武质熔体随着堆晶间隙分离结晶往富Fe和Ti的方向演化,改造早期形成的高铝型铬铁矿并结晶高铬型铬铁矿,同时生成金红石、钛铁矿和榍石等富Ti矿物相。     

Evolution of the Acipayam (Denizli,Turkey) Rodingites

Numerous diabase and gabbro dikes intrude the Lycian peridotite thrust sheet of southwestern Turkey. Some of the dikes are rodingitized and the host harzburgite is serpentinized. The present study demonstrates that the major episodes of serpentinization (of harzburgite) and rodingitization (of dikes) predated the obduction of the Lycian peridotite thrust sheet. Hydrogrossular veins, which represent the major event of calcium metasomatism in the dikes, are locally fractured, fragmented, and offset. High-field-strength-element concentrations and Ta/Yb-Th/Yb ratios in the mafic rocks suggest that the dikes were originally emplaced in an island-arc environment; thus, they must have been transported to their current location.

Fluid-inclusion microthermometry obtained on primary fluid inclusions in hydrogrossulars indicates that the fluid involved in rodingitization and contemporaneous serpentinization was moderately saline (8 equiv. wt% NaCl) and within the range of 250°-450°C. The above salinity and temperature are consistent with microthermometric measurements obtained from rodingite minerals worldwide.

It is apparent from our study that rodingite geochemistry and mineralogy provide valuable information on the tectonic and metamorphic evolution of a region. Trace-element and REE geochemistry can define the tectonic setting of dikes, detailed mineralogy of the dikes and host serpentinite provides information on the relative timing of serpentinization and contemporaneous rodingitization, and fluid-inclusion microthermometry provides information on the temperature and composition of the Ca-rich metamorphic fluids.     

Subvolcanic gabbro–porphyrite and intrusive diorite,and sulfide mineralization of the Dzhusa volcanogenic massive sulfide deposit (Southern Urals)

Two sequentially formed groups of dikes in the gabbro–porphyrite complex have been distinguished, the ages of which are early Eifelian (early dikes) and early Givetian (late dikes). We have estimated the temperature impact of ore contact metamorphism, which is related to dikes of the Lower Carboniferous Magnitogorsk intrusive complex. A hidden zonality of microimpurities in the ore-forming minerals has been established for the first time by the LA-ICP-MS method. The ore formation age has been determined as early Eifelian–early Givetian.     

Controls of Acid-sensitive Minerals on Reservoir Sensitivity Testing: An Example from the Silurian Kepingtage Formation in Tazhong Area, Tarim Basin

The Silurian Kepingtage Formation in Tazhong area is regarded as an acid-sensitive hydrocarbon reservoir. However, formation mechanism of acid-sensitive of the reservoir cannot be interpreted by the existing acid-sensitive evaluation criterion based on damage rate. The contents of acid-sensitive minerals illustrated by bulk-rock XRD, scanning electron microscopy and clay mineral composition analysis exert the dominant control on acid-sensitive flow testing of the reservoir. The iron-bearing minerals (including pyrite cements and chlorite cements) mainly deteriorate reservoir quality, while the iron-free minerals (including calcite cements and dolomite cements) mainly improve permeability. The permeability variation of the tested samples is controlled by the relative content of two acid-sensitive minerals. On the basis of newly established sensitivity mechanism and its influence on permeability, the corresponding ion (Fe2+) stabilizer was added to the acidizing fluids during the acidification reconstruction, which inhibited the negative factors of acid-sensitive minerals and improved the target layer quality effectively.     

Fracture propagation associated with dike emplacement at the skaergaard intrusion,east Greenland

Extensive magmatic activity, including several episodes of dike emplacement, was associated with early Tertiary continental rifting in Eastern Greenland. Exposures of the Skaergaard intrusion host a large number of these dikes as well as a variety of hydrothermal veins. One vein set has a characteristic outcrop expression and is filled with silica-rich chlorites. Relative timing constraints as well as the distribution and geometric relations of these veins relative to the mafic dikes indicate that at least some of these fractures formed during the emplacement of the dikes that cut the intrusion. Calculations based on elastic theory permit modeling of dike geometries observed in the field and prediction of fracture geometries that could be associated with the inflation of these dikes. Extensional fractures may form in the area ahead of the dike termination for a variety of loading conditions. The predicted width to length ratio for the dike as well as the size of the predicted fracture zone increases with increasing magma pressure within the dike and/or increasing differential between the remote principal stresses. For dike geometries similar to those observed in the field, the predicted fracture zone is roughly elliptical in cross-section and is centered in front of the dike termination. The size of the zone perpendicular to the dike trend varies from less than one meter to several meters. Field observations indicate that dike-parallel fractures are locally offset normal to the dike margin by distances of a few centimeters to a few meters. Our analysis implies that at least some of these fractures initiated and propagated ahead of the dikes as they were emplaced. The cooling of these dikes initiated localized hydrothermal systems that formed the vein minerals currently filling the fractures.