Yangshan Gold Deposit:The Largest Carlin and Carlin-like Type Gold Deposit in China

Gold Headquarter of the CAPF has discovered the Yangshan super large-scale gold deposit in Gansu Province, which is a great breakthrough of gold exploration and prospecting in Western Qinling Mountains of China. The gold resources of this deposit achieved 308 tons with increasing potentials. Preliminary geological investigations indicate that the Yangshan gold deposit is located in the intra-continental collision orogenic belt; and the deposit was formed during the continent-continent collision orogenic processes. The geological characteristics of the deposit are similar to that of the typical Carlin-type gold deposits, while differences still exist. The ore-forming background is notably different from the Carlin gold deposit province in the United States; and the ore-forming fluids are similar with that of the orogenic-type gold deposit. Accordingly, the Yangshan gold deposit is a transitional type between the Carlin-type and the orogenic type gold deposits. At present, the Yangshan gold deposit is the largest Carlin and Carlin-like type gold deposit that is ever discovered in China. Researches on metallogeny, metallogenic model and ore-enrichment regularities of the Yangshan gold deposit are crucial to meet the pressing needs of the current geological investigation and ore exploration of the deposit.     

Comparative Study of Gacun and Youre Silver–Lead–Zinc–Copper Deposits in Sichuan, SW China, and their Mineralization Significance

The large Gacun silver–lead–zinc–copper deposit in Sichuan Province is one of the largest volcanogenic massive sulfide(VMS) deposits in China. The deposit consists of western and central ore bodies, which form a vein–stockwork mineralization system corresponding to hydrothermal channels, and eastern ore bodies, which form an exhalative chemical sedimentary system derived from a brine pool in a submarine basin. The Youre lead–zinc deposit, which is currently under exploration and lies adjacent to the southern part of the Gacun deposit, is characterized by intense silicification and vein–stockwork structures and consists of massive silicified rhyolitic volcanics, banded rhyolitic tuff, and phyllitic sericite tuff. From a comparison of their ore-bearing horizons, the Gacun and Youre deposits have a continuous and stable hanging wall(calcareous slate and overlying andesite) and foot wall(rhyolite–dacite breccia and agglomerate), and the lithologic sequence includes lower intermediate to felsic rocks and upper felsic rocks. Thus, the Youre deposit, which comprises relatively thinly layered low–grade ore, is regarded as forming a southward extension of the Gacun deposit. A further comparison of the structures of the ore-bearing belts between the two deposits suggests that the Youre ore bodies are similar to the western ore bodies of the Gacun deposit. Moreover, the characteristics of fluid inclusions and stable isotopes in the Youre deposit are also similar to those of the western ore bodies of the Gacun deposit. Genetic models of the deposits are proposed for the Gacun–Youre ore district, and massive concealed ore bodies may occcur in the Youre deposit at depths that are similar to those of the eastern ore bodies of the Gacun deposit.     

http://www.sciencedirect.com/science/article/pii/S1674987113000790

The Heilangou gold deposit is located in the northern QixiaePenglai gold belt, which is one amongst the three large gold belts in the eastern Shandong Province （Jiaodong Peninsula）. The ore body has formed within the Guojialing granite. In this study, we report the mineral chemistry of pyrite, as well as the S, Pb, and HeO isotope data of the Heilangou gold deposit. The chemical composition of pyrite in the Heilangou gold deposit indicates that the associated gold deposit is a typical magmatic hydrothermal one. The geochemical signatures and crystal structure of pyrite show that the ore-forming materials have been derived from the crust. The S isotope data of the pyrites from Heilangou show an overall range from 5.5 to 7.8＆amp;and an average of 6.7＆amp;. The S isotope data in this deposit are similar to those from the deposits in the Jiaodong gold belt. The Pb and S isotope variations are small in the Heilangou gold deposit. The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios are 17.4653e17.5958, 15.5105e15.5746 and 38.0749e38.4361, respec-tively. These data plot between the lower crust and the orogenic belt. The Pb isotope data in the Heilangou gold deposit are similar to those in the Linglong gold deposit. From the Qixia gold area （the Liukou and Majiayao gold deposits） to the MupingeRushan gold belt （Rushan gold deposit） to the ZhaoeYe gold belt （the Linglong, Sanshandao and Jiaojia gold deposits）, the 206Pb/204Pb ratios progressively increase. The DeO isotope data obtained from quartz separates suggest that the ore-forming fluid was similar to a mixture of magmatic and meteoric waters. These results suggest that the ore-forming elements were primarily from source fluids derived from the lower crust.     

Selenium Enrichment in Cambrian Stratabound Gold Deposits in the Western Qinling Mountains

Stratabound gold deposits in the western Qinling Mountains occur in Cambrian chert formation composed of carbonaceous chert and carbonaceous slate. The distinctive chert formation provides important grounds for the mineralization and controls on the formation of gold deposits. Study shows that Se is exceptionally higher in both host rocks and gold orebodies. It may be recovered as a valuable component in ores for total utilization, and in some localities even independent Se orebodies (which are mined exclusively for Se) may be delineated. In gold ore Se mainly occurs as independent minerals or in the isomorphous form in sulphides and there is a positive correlation between Se and Au.     

New ~(40)Ar/~(39)Ar Data of Gold Mineralization in the Ailaoshan Gold Belt,Yunnan Province,China

正Objective"Orogenic gold deposits,"which account for 30%of global gold resources (Frimmel and Hennigh,2015),is one of the most important types of gold deposits in the world.This kind of gold deposit is supposed to have spatial and temporal distribution association with the accretionary orogenic belt.The Ailaoshan Gold Belt,where there are many large orogenic gold deposits including Jinchang,Daping,Laowangzhai,Donggualing,and Changan,contribute substantially to Chinese gold resources.The Himalayan orogen and Ailaoshan Orogen,both have experienced the early accretionary orogenesis and the subsequent collisional orogenesis are one of the     

Geological and Geochemical Characteristics of the Zhulazhaga Gold Deposit in Inner Mongolia, China

Located in Alxa Zuoqi (Left Banner) of Inner Mongolia, China, the Zhulazhaga gold deposit is the first largescale gold deposit that was found in the middle-upper Proterozoic strata along the north margin of the North China craton in recent years. It was discovered by the No. l Geophysical and Geochemical Exploration Party of Inner Mongolia as a result of prospecting a geochemical anomaly. By now, over 50 tonnes of gold has been defined, with an average Au grade of 4 g/t. The ore bodies occur in the first lithological unit of the Mesoproterozoic Zhulazhagamaodao Formation (MZF), which is composed mainly of epimetamorphic sandstone and siltstone and partly of volcanic rocks. With high concentration of gold,the first lithological unit of the MZF became the source bed for the late-stage ore formation. Controlled by the interstratal fracture zones, the ore bodies mostly appear along the bedding with occurrence similar to that of the strata. The primitiveore types are predominantly the altered rock type with minor ore belonging to the quartz veins type. There are also some oxidized ore near the surface. The metallic minerals are composed mainly of pyrite, pyrrhotite and arsenopyrite with minor chalcopyrite, galena and limonite. Most gold minerals appear as native gold and electrum. Hydrothermal alterations associated with the ore formation are actinolitization, silicatization, sulfidation and carbonation. A total of 100 two-phase H2O-rich and 7 three-phase daughter crystal-beating inclusions were measured in seven goldbearing quartz samples from the Zhulazhaga gold deposit. The homogenization temperatures of the two-phase H2O-rich inclusions range from 155 to 401℃, with an average temperature of 284℃ and bimodal distributions from 240 to 260℃ and 300 to 320℃ respectively. The salinities of the two-phase H2O-rich inclusions vary from 9.22wt% to 24.30wt% NaCl eqniv, with a mode between 23 wt% and 24wt% NaC1 equiv. Comparatively, the homogenization temperatures of the threephase daughter crystal-beating inclusions vary from 210 to 435℃ and the salinities from 29.13wt% to 32.62wt% NaCl equiv. It indicates that the ore-forming fluid is meso-hypothermal and characterized by high salinity, which is apparently different from the metamorphic origin with low salinity. It suggests a magmatic origin of the gold-bearing fluid. The δ^18O values of quartz from auriferous veins range from 11.9 to 16.3 per mil, and the calculated δ^18OH2O values in equilibrium with quartz vary from 1.06 to 9.60 per mil, which fall between the values of meteoric water and magmatic water. It reflects that the ore-forming fluid may be the product of mixing of meteoric water and magmatic water.Based on geological and geochemical studies of the Zhulazhaga gold deposit, it is supposed that the volcanism in the Mesoproterozoic might make gold pre-concentrate in the strata. The extensive and intensive Hercynian tectono-magmatic activity not only brought along a large number of ore-forming materials, but also made the gold from the strata rework. It can be concluded that the ore bodies were mainly formed in late hydrothermal reworking stage. Compared with typical gold deposits associated with epimetamorphic clastic rocks, the Zhulazhaga deposit has similar features in occurrence of ore bodies, ore-controlling structure, wall-rock alterations and mineral assemblages. Therefore, the Zhulazhaga gold deposit belongs to the epimetamorphic clastic rock type.     

The Kiloton Class Jiaojia Gold Deposit in Eastern Shandong Province and Its Genesis

The recent deep prospecting results in the Jiaojia area of Eastern Shandong Province indicate that the Jiaojia ore field composed of several individual gold deposits as previously suggested is actually an ultra-large gold deposit. This deposit covers an area of ~40 km2, and shows a structural control by the Jiaojia fault and its secondary faults. Gold orebodies generally occur along the same mineralization-alteration belt, and the main orebodies intersect with each other or exhibit a parallel or overlapping distribution. This deposit's reserves are estimated to be 1, 200t of gold, being the first gold deposit of more than 1000t gold reserves in China. The No. I-1 orebody in the Shaling-deep Sizhuang ore blocks holds gold reserves greater than 350 t, or 29 percent of the total reserves, followed by the No. I orebody in Matang-Jiaojia ore blocks with exceeding 150t gold reserves. This deposit mainly occurs in the footwall of the Jiaojia fault, and presents zoned patterns in mineralization, alteration and structures. The strongly mineralized zones agree with strongly altered and tectonically fractured zones. These orebodies display strataform-like, veinlike or lenticular shapes, and generally show characteristics of pinching out and reappearing, branching and converging, expanding and shrinking. The orebodies commonly occur along positions where the fault strike changes and in gentle locations with dips changing from steep to gentle. The main orebodies are parallel to the main plane of the orecontrolling fault, and tend to be gentle from the surface to the deep. The orebodies mainly plunge to the southwest, with plunge angle of 45°–60°. Orebodies near the main plane of the ore-controlling fault have more gold resource than those away from main fault zone. The slant depth of orebodies is generally larger than the length along its strike direction; orebodies become thick and gold grades become low from the shallow area to the deep area. Ore-forming fluids are H2O-CO2-NaCl±CH4 type with medium-temperature and moderate to low salinity. Sulfur isotopic values(δ34SCDT) for gold ores range between 11.08‰ and 12.58‰, indicating mixed sulfur sources; hydrogen isotopic values(δDVSMOW) range from-83.68‰ to-116.95‰ and oxygen isotopic values(δ18OV-SMOW) range between 12.04‰ and 16.28‰. The hydrogen and oxygen isotopes suggest that ore-forming fluids originated from primary magma, and mixing with a large amount of atmospheric water during the late stage. The Eastern Shandong Province gold deposits are associated with magmatic activities which have mantlecrust-mixed source, and also share some similarities with orgenic and epithermal hydrothermal gold deposits. Because Eastern Shandong Province gold deposits with unique metallogenic features and formation setting which are different from other gold deposit types in the world, we call it the Jiaojiatype gold deposits. The kiloton class Jiaojia gold deposit is related to fluid activities, extension and detachment resulted from thermal upwelling of magmas. The strong magmatic activities in the middle to late stage of early Cretaceous in Eastern Shandong Province lead to active fluids, and provided abundant ore-forming materials for gold depsoits. Moreover, many extensional structures resulting from crustal extension provided favourable space for orebody positioning.     

Biomineralization in the La'' erma Gold Deposit of the Western Qinling Mountains

Geological and geochemical studies and experiments on mineralization indicate that the source bed of the La' erma gold deposit in the south subbelt of the western Qinling Mountains is hydrothermal cherts in the Cambrian Taiyangding Group. Organic geochemical study of the cherts shows that the organic precursors intimately associated with gold are marine bacteria and algae. The gold content in chert,is positively correlated with the amount of bacterial and algal microfossils, and simulation experiments on biomineralization of modern bacteria and algae indicate that bacteria and algae played an important role in the formation of the La' erma gold deposit.     

日本西南部四国增生复合体中的锰矿分布

Bedded manganese ore deposits occur in many localities within the accretionary belts of the Shikoku region, SW Japan. The deposits occur mostly in bedded chert or its metamorphosed equivalent. These chert-hosted manganese deposits are considered to have been manganese nodule/crust-bearing siliceous sediments on deep-sea floor and have been converted to manganese ores by low-grade metamorphism through subduction-accretion process. The mineral assemblages of the ores reflect the metamorphic grade of the accretionary complexes. On the other hand, iron-manganese deposits and some manganese deposits occurring directly over basalt are considered to have been the hydrothermal precipitates associated with submarine volcanism.     

Trace Elements in Sphalerite from the Dadongla Zn-Pb Deposit, Western Hunan–Eastern Guizhou Zn-Pb Metallogenic Belt, South China

The western Hunan–eastern Guizhou Zn-Pb metallogenic belt is one of the important Zn-Pb mineralization regions in China. The Dadongla deposit, located in the northeast of Guizhou Province, is one of the typical Zn-Pb deposits in the region and has estimated resources more than 12 million metric tons (Mt) with an average grade of 4.11 wt% Zn+Pb. Its orebodies are hosted in the lower Cambrian Aoxi Formation dolomite, occurring as bedded, para-bedded in shape, and in conformity with the wall rock. The ore mineral assemblage is simple, dominated by sphalerite with minor pyrite and galena, and the gangue minerals are composed of dolomite, calcite with minor bitumen and barite. In view of the lack of geological and geochemical researches, the genesis of Zn-Pb ore is still unclear. Laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) spot and mapping analyses were used to obtain sphalerite trace element chemistry in the Dadongla Zn-Pb deposit in Guizhou, China, aiming to constrain its ore genesis. The results show that sphalerite is characterized by the enrichment of Cd, Fe, Ge and Hg, corresponding with that of typical MVT deposits. Four zones were identified in the sphalerite crystal from Dadongla from the center to margin according to the color bands, in which the zone in the center, representing the early ore-stage sphalerite, is characterized by enrichment of Cd relatively, while the zone forming at late ore-stage is enriched in Ge and Hg relatively. The finding was controlled by differential leached metals content in ore-forming fluid from its source rock. Notably, critical element Ge trends to be enriched at the late ore-stage and follows a substitution of 2Zn2+? Ge4++□ (vacancy). Moreover, the calculated ore-forming temperature ranges from 79.9°C to 177.6°C by the empirical formula, which is similar to that of typical Mississippi Valley-type (MVT) deposits. Compared with the features of trace elements in sphalerite from different types of deposits, together with the geology, the Dadongla deposit belongs to an MVT Zn-Pb deposit.     

西秦岭寒武系中金矿床成矿元素分带研究

西秦岭寒武纪硅岩建造中的金矿床,其形成与成矿热液沿纵向、横向及轴向的渗滤和扩散作用密切相关。由于元素组分在各个方面出现浓度（含量）的差异,使矿床中成矿元素分带甚为明显。元素的分带最终导致了Ａｕ、Ｓｅ、Ｕ、Ｃｕ、Ｍｏ、Ｓｂ、Ｈｇ等元素在三维空间各自构成单一或复合型的矿（化）体。     

拉尔玛-邛莫金矿床的地质特征及成矿模式

拉尔玛-邛莫金矿床产于西秦岭南亚带寒武系硅岩建造中,受地层、岩性、构造控制十分明显.但与其它层控金矿床相比较,该矿床不仅含矿主岩特殊,而且矿石矿物和元素组合十分复杂.矿床中除Au外,Cu、U、Mo、Sb、V、Zn等元素在局部地段亦可圈出独立矿体.同时,矿床中存在铂族元素(PGE)、铟的高异常以及硒的矿化富集体,从而构成了Au-Cu-U-Mo-Se-PGE建造矿床.研究表明,金矿床的形成,至少经历了喷流沉积和地下水热液活动改造两个成矿期.前者表现为硅岩建造中出现了众多成矿元素的高异常和黄铁矿等条带状、层纹状构造的形成,显示出矿质的初步聚集;后者则促使矿质富集层中的成矿物质组分发生活化、迁移和再聚集,并最终导致工业矿床的形成.矿床属与海底喷流作用有关的喷流型层控金矿床.     

西秦岭寒武系硅岩建造喷流沉积作用与矿质聚集

硅岩建造是西秦岭拉尔玛－邛莫层控金矿床的含矿岩系。含矿层状硅岩呈块状、条带状、层纹状、多孔状和同生角砾状等,单层厚度一般为３０ｍ－２００ｍ。主要成分ＳｉＯ２平均含量高达９５．３０％,其余为ＦｅＯ、Ｆｅ２Ｏ３和有机炭等。硅质的Ａｌ／（Ａｌ＋Ｆｅ＋Ｍｎ）比值低于０．３５（平均０．１５３）。硅岩中微量元素十分丰富,不仅含具基性、超基性特征的元素群（如Ｃｕ、Ｃｒ、Ｐｔ、Ｐｄ、Ｏｓ等）,而且含具酸性特征的元素群(如W、Mo、U等)．硅岩中稀土以总量低(32.9×10^-4～100×10^-4)、δCe亏损为特征．经北美页岩标准化后．稀土含量随原于序数的增大而增大．硅岩的δ180值为l7.60‰ ～23.24‰,其形成温度约为7O℃～l18℃.硅岩的δ30Si值主要在+O.4％～+O.8％之间,硅岩的上述特点均显示其与喷流沉积作用有美．喷流沉积作用不仅形成了特殊的硅岩建造,而且也使金等元素在硅岩建造中发生了明显的聚集。     

拉尔玛海底喷流成因硒-铜-铀-镍-钼-铂族元素-金矿床

西秦岭南亚带的拉尔玛Se-Cu-U-Ni-Mo-PGE-Au矿床是迄今为止我国仅见的与海底喷流作用有关的金矿床。它赋存于寒武系太阳顶群中，受地层控制明显。太阳顶群由硅岩、泥质硅岩和板岩组成，厚度近千米。现已发现的矿体，80%以上产于硅岩中。控矿的硅岩乃海底喷流的产物，海底喷流作用也导致了Au、PGE、Se以及其它成矿元素的富集，是贵金属元素的主要来源。尤为重要的是，近来在硅岩中发现了Se的矿化现象。因此该矿床是一个较典型的、海底喷流成因的硒-贵金属矿床。     

西秦岭寒武系层控金矿床中成矿元素富集规律

产于西秦岭南亚带寒武系硅岩建造中的金矿床, 是我国境内发现的一种与海底喷流作用有关的、具有独特地质特征的层控金矿床。成矿元素富集规律研究表明, 矿床中富集的元素种类十分丰富, 不仅含有具基性、超基性特征的元素群, 而且含有具酸性特征的元素群, 元素组合相当复杂。除Ａｕ 外, Ｃｕ、Ｕ、Ｍｏ、Ｓｂ、Ｖ、Ｚｎ等在局部地段亦可圈出独立的矿体。尤为重要的是, 矿床中铂族元素（ＰＧＥ）、分散元素（Ｓｅ、Ｉｎ） 的富集程度达到了综合利用的程度, 从而构成特殊的Ａｕ－Ｃｕ－Ｕ－Ｍｏ－Ｓｅ－ＰＧＥ建造矿床。     

建德铜矿床的海底喷流沉积成因

建德铜矿床是浙江西部多金属成矿带中一个引人瞩目的重要矿床。它产于中石炭统底部伴有火山岩、硅质岩和碧玉岩的白云岩中。整合块状矿体之下有一筒状矿化蚀变带。其成分以Ｃｕ＞Ｚｎ＞Ｐｂ为特征。根据矿床地质、地球化学特征以及近年来研究所获得资料，认为该矿床属海底喷流沉积成因     

甘肃省肃南县桦树沟铁铜矿床地质特征及成矿模式

甘肃北祁连西段桦树沟铁铜矿床是西北地区一个非常重要的铁铜矿床,对其地质特征及成矿模式的研究,将会对研究该成矿带铁铜矿床的成矿模式具有深远意义。通过大量的工作,认为桦树沟铁铜矿床为产于长城系上岩组的一套陆源碎屑岩夹碳酸沉积建造的同生海底喷流沉积矿床。铁矿体控矿构造主要是区域褶皱带,主要赋存于长城系上岩组的含铁细碎屑—粘土岩建造中,具体岩性为千枚岩。铜矿体的产出明显受后期韧性剪切带和层间滑动带共同控制,主要矿石类型有含铁碧玉岩型和蚀变千枚岩型两种。     

拉尔玛硅岩型金—铜—铀建造矿床的海底喷流沉积特征及找矿方向

西秦岭南亚带中的拉尔玛硅岩型金-铜-铀矿床,是一个比较典型的与海底喷流作用有关的金矿床。矿床赋存于寒武系太阳顶群中。太阳顶群地层由硅岩、板岩组成,厚度近千米。现已发现的矿体,80％以上产于硅岩中。硅质岩的地质地球化学特征表明,它是海底喷气沉积作用的产物,拉尔玛金-铜-铀建造矿床也具有海底喷流的沉积特征。     

赣东北地区金矿床类型、地质特征及找矿方向

赣东北是重要的黄金生产基地,金矿类型众多,成矿条件优越.依据成矿物质来源、成矿作用、矿床产出条件、矿石建造和围岩蚀变等因素,将赣东北地区岩金矿床划分为岩浆热液类、火山-次火山热液类、多源热液类和地下热(卤)水渗滤类等4类8型,分述了各类(型)金矿成矿地质特征,总结了沉积建造、构造和岩浆岩对区内金矿的控制作用,指出了赣东北地区金矿找矿方向.     

安徽铜陵黄狮涝山金矿床地质特征及成因

黄狮涝山金矿床为一铁帽型金矿床，其形成具复杂演变史。笔者通过野外观察和室内综合研究，认为矿床形成经历了三期成矿作用，其中第一期喷气沉积成矿作用和第三期风化淋滤成矿作用最为重要，是矿床两个主要成矿期，第二期热液叠加成矿作用对矿术形成有一定贡献，但不具有主导地位。最后，笔者讨论了风化淋滤过程中金的富集规律并指出了形成此类矿床的地质－地理条件。