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1.
The Dongfengnanshan Cu polymetallic deposit is one representative deposit of the Tianbaoshan ore district in the Yanbian area, northeast(NE) China. There occur two types of ore bodies in this deposit, the stratiform ore bodies and veintype ones, controlled by the Early Permian strata and the Late Hercynian diorite intrusion, respectively. Due to the ambiguous genetic type of the stratiform ore bodies, there has been controversy on the relationship between them and veintype ore bodies. To determine the genetic type of stratiform ore bodies, laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) in situ trace elements and S–Pb isotope analysis have been carried on the sulfides in the stratiform ore bodies. Compared with that in skarn, Mississippi Valley-type(MVT), and epithermal deposits, sphalerite samples in the stratiform ore bodies of the Dongfengnanshan deposit are significantly enriched in Fe, Mn, and In, while depleted in Ga, Ge, and Cd, which is similar to the sphalerite in volcanic-associated massive sulfide(VMS) deposits. Co/Ni ratio of pyrrhotites in the stratiform ore bodies is similar to that in VMS-type deposits. The concentrations of Zn and Cd of chalcopyrites are similar to those of recrystallized VMS-type deposits. These characteristics also reflect the intermediate ore-forming temperature of the stratiform ore bodies in this deposit. Sulfur isotope compositions of sulfides are similar to those of VMS-type deposits, reflecting that sulfur originated from the Permian Miaoling Formation. Lead isotope compositions indicate mixed-source for lead. Moreover, the comparison of the Dongfengnanshan stratiform ore bodies with some VMStype deposits in China and abroad, on the trace elements and S–Pb isotope characteristics of the sulfides reveals that the stratiform ore bodies of the Dongfengnanshan deposit belong to the VMS-type, and have closely genetic relationship with the early Permian marine volcanic sedimentary rocks. 相似文献
2.
安徽铜陵冬瓜山铜(金)矿床成矿模式 总被引：22，自引：11，他引：11
长江中、下游断裂坳陷带是我国重要的铜、金、铁、硫成矿带,存在一系列块状硫化物矿床及与其伴生的矽卡岩型和斑岩型矿床.本文以铜陵矿集区冬瓜山铜、金矿床为例,探讨了这类矿床的成矿模式.冬瓜山矿床主要由层状硫化物矿体组成,伴有矽卡岩型和斑岩型矿体.层状硫化物矿体产于晚泥盆世砂岩和晚石炭世碳酸盐岩之间,具明显的层控特征,矿体下盘发育细脉-网脉状硫化物矿化以及硅化和绢云母化,矿体中伴有热水沉积岩,矿石具典型的沉积构造.燕山期岩浆热液对层状矿体进行了叠加和改造,改变了矿石的结构构造和矿石成分.黄铜矿交代黄铁矿变斑晶呈环斑结构或脉状交代结构,交代磁黄铁矿呈交代假象结构或交代残留结构.矽卡岩型矿体中黄铜矿的δ65Cu值为0.09‰～0.83‰,集中在0.23‰～0.83‰.层状矿体中黄铜矿的δ65Cu值为0.45‰～0.78‰,与矽卡岩矿体中黄铜矿的65Cu值大致相当,这说明两类矿体中的铜具有相同的来源.铜、氢和氧同位素研究表明,冬瓜山矿床铜来自岩浆岩,叠加的成矿流体主要为岩浆流体.提出了冬瓜山矿床属喷流沉积-岩浆热液叠生成因的成矿模式:在晚石炭世,海底喷流成矿作用形成了块状硫化物矿床,矿石成分以硫、铁为主;燕山期岩浆热液一方面对块状硫化物矿床进行改造,致使其富集铜等成矿物质,另一方面与围岩相互作用形成矽卡岩型和斑岩型矿体. 相似文献
3.
Abstract. Formation conditions of some vein-type copper deposits of the Tocopilla district (Deseada, San Jose, Santa Rosa) and the Gatico district (Yohanita, Toldo-Velarde, Argentina) in the Coastal Cordillera of northern Chile were inferred from mineral paragenesis and fluid inclusion data, and were compared with those of neighboring stratiform copper deposits. The vein-type copper deposits are hosted in Late Jurassic dioritic to quartz-dioritic plutons intruding extensively an andesite-dominant volcanic pile of the Jurassic La Negra Formation. Primary mineralization is characterized by chalcopyrite + magnetite + pyrite + bornite, and supergene alteration of these minerals produced anilite, covellite, atacamite and chrysocolla. The hypogene mineral assemblage indicates relatively high sulfur fugacity and weakly oxidized conditions, distinct from the stratiform copper deposits formed under low sulfur fugacity and moderately oxidized conditions. Furthermore, the fluid inclusion data of the vein-type deposits indicate high temperature (401–560C) and high salinity (39–68 wt% NaCl equiv.) ranges in contrast to the stratiform deposits, suggesting that this type of deposits formed by magma-associated hypersaline ore fluids. 相似文献
4.
沉积型铜矿作为重要的铜矿类型之一,一直是工业界找矿和开发的重点。中非铜(-钴)矿带是世界著名的巨型沉积型铜矿带之一。赞比亚谦比希铜矿是我国企业在非洲矿业开发的成功典范项目,其矿体分布和产状严格受新元古代加丹加超群的下罗恩组地层控制,含矿岩石为下罗恩组下部的含矿泥质页岩、砂岩。本文通过对谦比希铜矿的矿床地质特征、成矿地质背景、成岩-成矿规律的详细研究,揭示了其含矿地层和矿体明显受古沉积环境、基底形态的控制;成岩-成矿过程经历了海侵-海退过程,沉积古地理环境为滨浅海蒸发背景。赞比亚铜带省和西北省拥有巨大的资源和找矿潜力,未来必将吸引更多投资。 相似文献
5.
Prof. Georges Monseur 《International Journal of Earth Sciences》1974,63(1):23-40
During the International Sedimentological Congress of Heidelberg (Germany), the author — in collaboration with his college J.Pel of the University of Liege (Belgium) — has emphasized the influence of the sedimentary rhythm about the location of the stratiform ore deposits in some facies of the reef environment and has proposed a first synthesis of the relations between several stratiform deposits of varying mineralogy and different ages also associated with reef complexes. In this paper, the author illustrates the sedimentological method used previously in resting principally on a comparative analysis of the ore conditions which characterize the stratiform lead zinc deposits of Reocin (Spain), Eastern Alps (Bavaria, Austria), Pine Point (Canada) and S. E. Missouri (United States). 相似文献
6.
Field observations and experimental results show that gold is mobile under a wide range of natural conditions in the surficial environment. However, the extent to which, and the form(s) in which gold was mobile in ancient placers remains speculative. Rather more convincing is the extent to which diagenetic and metamorphic processes have been active in redistributing the gold.Huronian paleoplacer gold deposits span a critical transition in Earth history, namely, the oxyatmoversion, evidence for which exists in the upper Gowganda Formation dated at 2.288 Ga. Prior to this transition, deposition of gold occurred under reducing atmospheric conditions, with transportation of the more finely-divided material possibly as organic-protected colloids, as has been suggested for the Witwatersrand. Following the oxyatmoversion, gold deposition will have been subject to secondary enrichment, like many Phanerozoic placer gold occurrences. For this reason, and on purely sedimentological grounds, upper Huronian strata ought to have as much potential for hosting economic deposits of gold as the basal units.A total of 121 Au and Au---U occurrences, including several past and presently producing mines from the Huronian Supergroup, are examined. These are classified according to whether mineralization is: in or adjacent to diabase dikes (11 cases); in (quartz, quartz—carbonate) veins (85 cases); stratiform (25 cases). Of the non-diabase-hosted occurrences, 41.3% occur in the Cobalt Group, 15.7% in the Quirke Lake Group, 24.9% in the Hough Lake Group and 9% in the Elliott Lake Group.Frequency of occurrence can be related to transgressive sedimentary cycles, with deposits concentrated in the Matinenda, Mississagi and Gowganda Formations, which immediately overlie the Archean—Huronian unconformity. Most of the deposits occur in the Gowganda Formation, although none of these is stratiform.In terms of Au content, there is a large overlap in class intervals of stratiform vein deposits. Vein deposits are, in general, richer than stratiform by a factor of 10. Selected stratiform deposits in the Matinenda, Mississagi and Serpent Formations are examined in light of available geological and geochemical data. In these deposits, anomalous gold values in dominantly quartzitic metasediments are accompanied by fine-grained pyrite and other heavy minerals, including uranium, which occurs in most, but not all cases. Metamorphic grade ranges from upper greenschist to lower amphibolite facies. A few of the stratiform occurrences are accompanied by accumulations of carbonaceous material, an association reminiscent of the Witwatersrand goldfields.Results of electron-microprobe study indicate that much of the gold in the Huronian metasediments occurs as low level concentrations in pyrite of morphologically different types, in arsenopyrite, chalcopyrite, and in pyrrhotite variously altered to marcasite. It is clear that Huronian paleoplacer gold deposits exist, but only in conditions much modified by diagenetic and metamorphic processes. 相似文献
7.
8.
Tran Tuan Anh I.V. Gas’kov Tran Trong Hoa P.A. Nevol’ko Pham Thi Dung Pham Ngoc Can 《Russian Geology and Geophysics》2012,53(7):623-635
The Pb–Zn deposits in the Lo Gam structure, northeastern Vietnam, account for>80% of all the Pb and Zn resources of Vietnam. All the deposits make up four isolated ore districts (Thai Nguyen, Cho Don, Cho Dien, Na Son), which can be combined in one metallogenic zone extending for >100 km from southeast to northwest. The Pb–Zn deposits in all the ore districts show some similarity to stratiform (Mississippi-type) deposits: confinement to Devonian carbonate sediments; localization at the intersection of faults of different orientations; vein and stockwork (pocket-vein-disseminated) morphology of the mineralized zones; evidence for hydrothermal-metasomatic formation (carbonate-rock marbleization, quartz–carbonate veins, etc.); and low and moderate mineralization temperatures (<250 °C). On the other hand, some differences from stratiform deposits are observed: widespread occurrence of Permo-Triassic igneous rocks in the above ore districts; absent tabular orebodies, which are typical of stratiform deposits; large set of trace elements (In, Bi, Sb, Au, Ag, Cu, Cd) not typical of stratiform deposits; and an endogenic primary source, as evidenced by the isotope composition of sulfur (δS34= 2.68‰), which is close to meteoritic, and the set of trace elements, which are mainly of deep genesis. All this indicates that the above Pb–Zn deposits within the carbonate units are low-and moderate-temperature hydrothermal-metasomatic products associated with active magmatism which took place in this region in the Permo-Triassic.The differences in the mineral composition of the deposits, as well as in the trace-element set and contents at different deposits, clearly indicate an intricate ore formation process and the relation of the deposits with magmatism of different compositions. The simple mineral composition and the limited set of trace elements (Cd, Ag, Sb, As) at the Lang Hich deposit are closer to the characteristics of stratiform deposits. Also, manifestations of magmatism are almost absent here. On the contrary, unusually high (ppm) In (75.8), Sn (307.5), Cu (1080), Ag (157.7), Bi (99), and As (13,650) contents were observed at the deposits of the Cho Don and Cho Dien districts, with widespread granitoid magmatism in the Phia Bioc complex. Rare-earth mineralization (orthite) and high Mo, Re, and Rb contents at the deposits of the Na Son district are probably due to the widespread occurrence of stratified alkaline volcanics and their subvolcanic analogs, which belong to the Pla Ma complex (ξγPZ2 pm). 相似文献
9.
The stratigraphic setting and geological environment of the Boorloo stratiform copper prospect is described. This prospect occurs in the Umberatana Group of the Adelaide Supergroup in the Willouran Ranges of South Australia. Stratiform copper mineralization occurs in stacked, braided, siliciclastic channels on the middle and distal portions of a late Proterozoic river-dominated delta. Comparison is made between this river-dominated delta copper system and the much larger river-dominated delta copper system of the Proterozoic Udokan deposit in the U. S. S. R. It is suggested that the traditional classifications of stratiform copper sensu strictu deposits as arenaceous-ore or oreshale can be viewed as dip-system or strike-system deposits respectively. 相似文献
10.
云南东川地区,元古界昆阳群落雪白云岩中规模巨大的层状铜矿,1941年由谢家荣命名为“东川式铜矿”[1],用以代表与闪长岩有关的岩浆热液矿床。李洪谟、王尚文(1941年)、孟宪民等(1948年)[3]对这一成因观点都有详细的论述。1960年后,孟宪民指出,东川铜矿可能为沉积成因。笔者在东川白锡腊、因民、落雪、汤丹等地,发现铜矿床中保留了很多沉积成岩的标志,同时根据脉状铜矿是变质脉、岩浆岩的同位素年龄小于层状铜矿等特征,从而提出了沉积变质的成因认识。1975年,桂林冶金地质研究所提出此类矿床应更名为火山—沉积—浅变质矿床[4]。近年来,通过对含矿层的岩相和岩石学的研究、铜矿与藻类叠层石关系的研究,笔者认为,“东川式铜矿”的成因不是单一的,是沉积成岩、蒸发成岩、变质改造等多成因、多阶段形成的一种复合矿床,本文就此进行了探讨。 相似文献
11.
The Timeball Hill and Silverton Formations of the 2.1–2.3 Ga Pretoria Group have regional lithological associations which are thought to have been favourable for the genesis of stratiform sulphide deposits. The observed association of carboniferous and pyritic black shales, tuffaceous material, stromatolitic carbonates and inferred turbidity current deposits is common in stratiform sulphide deposits of the sedimentary exhalative group. Massive sulphides in the Silverton Formation are compatible with a syngenetic brine discharge, probably related to deep fracture systems. The basal shales of the Timeball Hill Formation are significantly enriched in base-metals and Ba. Interlayered tuff beds at this stratigraphic level have PGE-contents of up to 1 g/t. The REE-geochemistry of Pretoria Group sedimentary rocks supports hydrothermal activity as an important factor in both stratigraphic units. 相似文献
12.
全球铬铁矿资源丰富,但分布极不均衡.铬铁矿的成因类型主要有层状和豆荚状2种,这2种类型的铬铁矿床地质特征、成因模式差异显著.在全球范围内铬铁矿矿床的成矿时代和空间分布具有明显的时空规律性,古元古代是铬铁矿最重要成矿期,该期形成的铬铁矿占总资源量的58.5％,以形成大型-超大型层状铬铁矿为主,中-新生代是全球铬铁矿床形成数量最多、分布范围最广的重要成矿期,该期形成的铬铁矿占总资源量的24.9％,以形成中小型豆荚状铬铁矿为主.铬铁矿在全球的分布可划分为5个重要层状铬铁矿矿田(南非布什维尔德-津巴布韦大岩墙、北美斯蒂尔沃特、南美坎坡福莫索、印度苏金达、芬兰凯米-俄罗斯普拉科夫斯科)和7个豆荚状铬铁矿带(津巴布韦舒鲁圭、东北非、乌拉尔、特提斯、西太平洋岛弧、加勒比岛弧和马达加斯加),并对各重要成矿区带的资源潜力进行了探讨.通过对全球铬铁矿成因类型、地质特征和时空分布规律的探讨,对深入了解地幔的物质组成、物理化学环境、地幔物质的运移、深部地质作用及板块运动的动力学机制、深俯冲和地球深部再循环轨迹有重要的理论意义. 相似文献
13.
Carbonate organogenic buildups (reefs) are lithofacies barriers of marine basins separating sedimentation facies zones. Together with seafloor depressions, they make up two-facies systems that are favorable for the formation of stratiform lead, zinc, and copper deposits. Organogenic reefs are formed at the boundary between the littoral zone and the remaining shelf area, as well as on terraces separating the shelf and continental slope zones. The reefs control the stratiform copper mineralization in the first case and the MV-type lead–zinc mineralization in the second case. This work describes the following reef systems of northeastern Asia incorporating base metal deposits: Chencha (Late Riphean) system of the Zhuya–Patom Trough, West Yakutian (Early–Middle Cambrian), Tankhai–Ust'mil (Middle Cambrian), and Lena (Late Cambrian) systems of the Siberian Platform, and Urul'tun (Early Devonian) and Kamenka (Middle Devonian) systems of the Omulev and Kolyma blocks. The two-facies genetic model of the MV-type lead–zinc and stratiform copper deposits is substantiated. 相似文献
14.
Lower Cambrian Black Rock Series and Associated Stratiform Deposits in Southern China 总被引：5，自引：1，他引：5
Widespread in more than ten provinces of southern China are the Lower Cambrian black argillaceous-arenaceous rock series consisting of black carbonaceous shales,black carbonaceousargillo-siliceous rocks,black carbonaceous silicolite and black silicolite and black carbonaceous argillaceous siltstone.The Ni,Mo,V,Cu,U,Ba,Ag,P contents of these series are usually several to tens of times higher than their average values in shales.As viewed from lithological sequence,element association and evolution,these black series can be diveided into two types.There occur a variety of deposits in the black rock series,such as phosphorite deposits,Ni-Mo-V polymetal deposits and “Stone coal“ seams.According to ore composition,texture and structure,the phosphorite deposits fall into three types,i.e.,thick-bedded,lenticular and nodular,The Ni-Mo-V polymetal deposits,V deposits and reworked sedimentary CU-U-Cd polymetal deposits in terms of their element assiciation and ore genesis.As for the stratiform deposits in the black rock series,three mineralization stages have been recognized,i.e.,the formation of phosphorite deposits,of Ni-Mo polymetal deposits and of V-Cu-U-Cd polymetal deposits as well as of “:stone coal“ seams.Evidence strongly suggests that lower organisms have played an important role in mineralization. Our studies indicate that the Lower Cambrian black argillaceous-arenaceous rock series in southern China and their associated stratiform deposits occur generally in the basal parts of a big sedimentary cycle,i.e.,the initial period of a transgression,or in the fine detrital-siliceous formation between two carbonate formatons,formed in a humid climatic zone between two arid ones.As for the environment of deposition,it is suggested that the Lower Cambrian black argillaceous-arenaceous rock series and associated stratiform deposits(excluding thick-bedded phosphorite deposits)were formed mainly in a restricted and poorly-fed sea basin of stagnant shallow water containing abundant lower or ganisms and organic matter under statically hydrodynamic conditions. 相似文献
15.
20世纪90年代以来，四川地矿局207地质队及地方采矿业在扬子地台西缘大渡河谷沿岸，相继发现了黑区—雪区、红花、白熊沟、核桃坪、养善坪—中溪坪—宝水溪—双凤沟等层状铅锌矿床及矿点。其中，黑区—雪区矿床的矿体地表露头长达6000m，估算的铅锌资源量达370万吨，达到超大型矿床的规模。不同的矿床、矿点的分布构成了长度大于50km的铅锌矿化带，预测铅锌资源量有望达1000万吨以上。各矿床、矿点产于上震旦统—下寒武统灯影组顶部麦地坪段含磷硅质白云岩的相同层位，矿化与硅质岩及角砾状白云岩层关系密切。矿床中发育层状、纹层状、条带状、同沉积角砾状、层间揉皱等构造，沉积特征明显。矿床的地质、地球化学特征显著区别于区域上以往发现的产于地台盖层碳酸盐岩中具有明显后生成因特点的密西西比河谷型（MVT型）铅锌矿床，也有别于产于中元古界褶皱基底中的火山沉积块状硫化物型（VMS型）铅锌矿床。笔者的研究表明，与铅锌矿密切共生的硅质岩为典型的海底热水沉积产物，铅锌矿床属于海底喷流—沉积成因（SEDEX型）；成矿作用受晚震旦世—早寒武世北东东向延伸的汉源—峨眉凹陷及同生断裂带的控制。该类层状铅锌矿床可能是扬子地台西缘铅锌矿聚区中最具找矿潜力的矿床类型。 相似文献
16.
以较详细的资料论述了秦岭凤太矿田层控铅锌(铜)矿床的主要成矿特征。包括反映成矿地质环境、成矿方式、成矿物质来源和成矿物理化学条件等方面的特征,据上述综合特征提出了海底喷气-沉积成矿模式。 相似文献
17.
甘肃西成地区层状的花岗质岩脉地质地球化学特征及其与金矿关系 总被引：4，自引：0，他引：4
西成地区小沟里和三洋坝金矿区发育层状的花岗质岩脉带，其成岩物质既有岩浆热液来源又有地层来源，反映了海西期秦岭裂谷扩张时岩浆热液顺层交代泥盆系岩层的成因特征；层状的花岗质岩脉与石英钠长岩等共同构成了西成地区泥盆纪热液交代，热水沉积所形成的层状交代沉积岩系；层状的岩脉与金矿床的空间关系密切是寻找金矿床的有效岩石标志。 相似文献
18.
试论层状铜矿的三种主要成因模式 总被引：8，自引：0，他引：8
层状铜矿是铜矿资源中仅次于斑岩铜矿的重要矿床类型,包含多种成因机制,历来有同生与后生之争。本文归纳了这类铜矿的３种成因模式,即“沉积－成岩”、“沉积－喷气”和“沉积－改造”模式,讨论了它们的不同特征和机制,以及三者之间的相互关系。文中对“沉积－改造”模式进行了重点讨论,并强调了这一成矿作用的意义。 相似文献
19.
桂西北盆-山构造系与大厂锡石多金属成矿作用 总被引：3，自引：1，他引：2
高计元 《大地构造与成矿学》1998,22(4):332-338
通过对区域地形形态、地质构造格架、大厂矿田的矿床地质、地球化学特征的研究,阐明了大厂矿区所处的构造位置为一盆-山构造系。大厂锡石多金属硫化物矿床的生成、发展和演化是该盆一山构造系发展演化的产物,受盆-山构造系的控制。本矿床按矿体形态、矿床特征可以分为层状矿化和脉状矿化两大类。层状矿化是盆-山构造系形成早期同生沉积的,严格受地层层位和岩性的控制。脉状矿化是盆-山构造系发展演化的晚期不同阶段中受岩浆热液作用的叠加、改造而成,受构造和层位的双重控制。 相似文献
20.
The Central African Copperbelt in Zambia and the Democratic Republic of Congo is the world's largest sediment-hosted stratiform Cu province. The source for the Cu in sediment-hosted stratiform Cu deposits is generally believed to be thick sections of oxidised siliciclastic sediments (red beds) and volcanic rocks deposited in early rift sequences underlying or laterally adjacent to the ore-bearing sediments. The volume of red beds beneath or lateral to the Zambian portion of the copperbelt relative to the amount of known metal in the deposits is small in comparison to the volumes of source beds in other well-known districts such as the Polish Kupferschiefer and the White Pine District, USA. Previous structural studies suggest that the rocks hosting the Zambian Cu deposits may be allochthonous or para-autochthonous. The apparent absence of source sediments for the metals, combined with the known structural geology, strongly suggests that the Zambian deposits were tectonically displaced from their source rocks. Defining the present location of the source basins would constrain the amount of tectonic transport in this portion of the Lufilian Arc and would stimulate mineral exploration in new areas. 相似文献