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1.
孟宪民将赋存于东川元古代昆阳群落雪白云岩中的层状铜矿命名为“东川式铜矿”。该类矿床广泛分布于康滇地轴昆阳群(会理群)落雪组地层中(图1),并严格受一定的岩性地层组合控制,基本上是沉积变质的或火山沉积变质的成层矿床。简而言之,就是一定层位的矿床。据此,笔者将这类矿床更名为“东川式层控铜矿”。此类矿床在成岩阶段就已基本形成,尔后经受各种地质作用(区域变质、地壳运动、次火山一岩浆 相似文献
2.
东川式铜矿的成矿作用及后期叠加改造:来自硫化物原位硫同位素的制约 总被引：2，自引：1，他引：1
沉积岩型层状铜矿床(SSC型)的成因争论聚焦在成矿作用主要集中在沉积成岩期并可能叠加有后期成矿作用,还是形成于成岩后盆地闭合过程和造山作用有关。产于扬子板块西缘的东川式铜矿是中国SSC型矿床的典型代表,这些矿床赋存在晚古元古界东川群岩石中,主要呈层状矿体产出,但也存在少量脉状矿体。文章选择东川铜矿田内因民、汤丹和滥泥坪3个典型矿床的层状和脉状矿体中硫化物(黄铁矿、黄铜矿、斑铜矿和辉铜矿)开展原位硫同位素组成的对比研究。实验结果表明,这些矿床的硫化物原位硫同位素组成分布范围较广:因民矿床层状硫化物的δ34S值分布于4.7‰~22.1‰,汤丹和滥泥坪矿床层状硫化物的δ34S值为-3.3‰~3.1‰;因民矿床脉状硫化物的δ34S值分布于21.0‰~30.7‰,汤丹和滥泥坪矿床脉状硫化物的δ34S值为-19.4‰~3.5‰。层状矿体和脉状矿体的硫化物硫同位素组成明显不同,表明形成2种产状矿体的硫来源不同。层状矿体较大的硫同位素组成差异指示了海相硫酸盐不同程度的热化学还原作用,表明初始成矿流体中的硫来源于循环盆地卤水中溶解的海相蒸发岩。脉状矿体的硫同位素组成则强烈受控于矿区的赋矿围岩,因民矿床硫化物中极高的硫同位素组成表明硫的来源为地层中的海相蒸发岩,而汤丹和滥泥坪矿床中亏损34S的特征则表明硫的来源为富含生物还原硫的碳质板岩。结合野外地质关系和前人研究成果,文章认为层状矿体和脉状矿体是2期独立成矿事件的产物,层状矿体形成于成岩作用时期,脉状矿体形成于后期独立的局部构造热成矿事件,也即SSC型矿床的成矿作用主要发生在成岩期,但普遍遭受后期热液活动的叠加,并且在不同的成矿期中可能存在着多阶段的成矿作用。 相似文献
3.
东川式层状铜矿40Ar-39Ar成矿年龄研究：华南地区晋宁-澄江期成矿作用新证据 总被引：14，自引：0，他引：14
本文采用^40Ar-^39Ar真空击碎技术和阶段加热技术，测定了采自落雪矿的“东川式”层状铜矿之两个石英样品的年龄，获得了810-770Ma的^40Ar-^39Ar等时线年龄，这是首次获得的“东川式”铜矿的成矿年龄。这些年龄与作者以前获得的脉状铜矿石英的年龄范围一致，远远小于赋矿围岩落雪组的年龄，研究结果表明“东川式”层状铜矿并非沉积成因，与脉状铜矿一样，也是热液成因，并且再次证实晋宁-澄江期是东川铜矿的主要成矿期。 相似文献
4.
东川式层状铜矿的沉积-改造成因 总被引：4，自引：0，他引：4
对于东川式层状铜矿的成因，前人多持“沉积-变质”观点。通过研究，本文提出“沉积-改造”成因的新认识。新观点认为，沉积阶段铜不是在落雪组富集，而是在因民组红层中富集。在成岩阶段或成岩后，沉积岩中的水分被裂谷的高热流所加热，并由于深断裂的减压作用所驱动而产生对流循环。这种盐度较高的热液能淋滤汲取因民组中的铜质，并在断裂带附近向上运移。当含铜热液上升到达落雪组底部时，便与那里由细菌还原的硫结合形成硫化物沉积，形成层状铜矿。这个由热液将因民组(矿源层)中的铜转移到过渡层和落雪组底部(赋矿层)中成矿的过程，就叫做“改造”作用，它既不同于成岩作用也不同于变质作用。本文由此总结了东川式层状铜矿的成矿模式为“红层预集一改造热液转移一藻白云岩成矿”。 相似文献
5.
东川铜矿是我国著名的铜矿区之一。前震旦系东川群落雪组白云岩中的铜矿,1941年谢家荣曾命名为东川式铜矿。其中有一种铜矿石呈细脉状,李洪谟、王尚文称为“马尾丝矿”,并认为它是岩浆热液沿灰岩叶理交代生成。谢家荣提出它是藻类组织,“为铜矿所交换或充填者”。1947年孟宪民也作了详细的研究。 1981年龚琳、王承克提出铜矿沿叠层石基本层分布,密集时可连成纹理,构成特有的“马尾丝”构造。“马尾丝”铜矿是富矿,含铜品位一般为1～3％。1984年,笔者在东川穿天坡东川群落雪组,采到一些铜质叠层石,现提出一些看法,对研究叠层石与铜矿 相似文献
6.
东川式层状铜矿的沉积-改造成因 总被引：1，自引：0，他引：1
对于东川式层状铜矿的成因,前人多持“沉积-变质”观点。通过研究,本文提出“沉积-改造”成因的新认识。新观点认为,沉积阶段铜不是在落雪组富集,而是在因民组红层中富集。在成岩阶段或成岩后,沉积岩中的水分被裂谷的高热流所加热,并由于深断裂的减压作用所驱动而产生对流循环。这种盐度较高的热液能淋滤汲取因民组中的铜质,并在断裂带附近向上运移。当含铜热液上升到达落雪组底部时,便与那里由细菌还原的硫结合形成硫化物沉积,形成层状铜矿。这个由热液将因民组(矿源层)中的铜转移到过渡层和落雪组底部(赋矿层)中成矿的过程,就叫做“改造”作用,它既不同于成岩作用也不同于变质作用。本文由此总结了东川式层状铜矿的成矿模式为“红层预集—改造热液转移—藻白云岩成矿”。 相似文献
7.
从区域地质背景、岩石学、岩石化学、微量元素、氧同位素及稀土元素组成等方面论证东川铜矿含铜“礁—硅岩组合”中的含铜硅质条带—硅质白云岩为海底喷流热水沉积成因；提出了该类层状铜矿的深源含铜富硅混合热液海底喷流—生物富集的沉积成岩成矿模式。并提出东川落雪式层状“马尾丝”铜矿含矿岩系为“含铜礁—硅岩组合”的新观点。 相似文献
8.
东川铜矿床是我国重要的沉积岩容矿的层状铜矿床(SSC),具有显著的多层位成矿特征和典型的铜硫化物分带。本研究以不同层位铜矿体的流体包裹体为研究对象,通过岩相学观察、显微测温和激光拉曼成分分析,发现东川群多层位铜矿体存在浅色和深色包裹体2种类型:浅色包裹体成分以H2O为主,含丰富的石盐子晶和少量钾盐、硬石膏子晶,代表了氧化型含矿卤水,具中低温(140~300 ℃)、中高盐度(12%~44%)的特征,属于Na +、K +、Ca 2+-Cl -(SO4 2-)型盆地卤水,主要来源于海相蒸发岩的溶解和层间建造水;深色的含有机质包裹体代表了还原型流体,来源于黑山组碳质板岩和落雪组中的藻类生物分解。东川铜矿床以落雪组的含叠层石砂质白云岩作为主要沉淀系统,黑山组碳质板岩为隔挡层,形成一个流体封闭的物理化学圈闭,氧化含矿卤水通过供给系统运移到具还原性质的沉淀系统中,与还原型富硫流体和含有机质的地层发生混合反应,形成多层位的层状铜矿体和层控脉状铜矿体。 相似文献
9.
云南东川人占石铜矿床地质特征及成因研究 总被引：1，自引：0，他引：1
[摘 要]云南东川人占石铜矿位于川滇元古宙铜多金属成矿带之滇中一带,是江苏省有色金属华东地质勘查局和云南金山矿业有限公司新近勘查开发的一个资源产地。本文重点报导了矿体特征、矿石岩石学矿物学特征,矿物生成顺序与共生、交代关系等矿床地质特征,并从这些实际材料出发,通过综合类比研究,对矿床成因进行初步讨论。研究表明,人占石铜矿床赋存于青龙山组灰白色厚层状白云岩中,系在中元古界裂谷环境的海盆沉积碳酸盐含矿层经变质成矿作用之后,在晋宁期又叠加了热液改造富集,可以归属于“东川式冶沉积变质叠加热液改造矿床,使东川地区原始含矿层位在继因民组、落雪组、黑山组、陡山沱组“四层楼冶之后,又增加了青龙山组一层,丰富了东川成矿模式内容,为本区进一步找矿工作提供理论和科学依据。 相似文献
10.
滇中易门县狮子山铜矿是产于扬子古陆边缘昆阳裂谷易门裂陷盆地内典型东川式层状矿床, 是在昆阳裂谷背景下经同生沉积和二次富集作用而成, 在鹅头厂组、落雪组、因民组等地层中均有不同矿体产出,矿床成因属热卤水沉积型东川式铜矿床。矿床的形成经历了同生阶段、成岩阶段和后生阶段。矿床在同生沉积阶段形成, 成岩阶段固结成岩, 后期的岩浆活动对矿床起到一定富集和改造作用。本文研究认为, 矿床受地层与岩性、岩相古地理、构造、岩浆岩等因素的控制, 通过对矿床成矿要素的分析和总结, 归纳了该区的找矿标志, 提出了矿区本部和近外围的找矿方向和靶区优选。 相似文献
11.
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
12.
《Ore Geology Reviews》2003,22(1-2):91-116
Sediment-hosted disseminated gold deposits in NW Sichuan China have many features in common with the well-known Carlin-type deposits in the western United States. They are hosted by Middle–Upper Triassic turbidites composed of 1300–4300 m of rhythmically interbedded, slightly metamorphosed calcareous sandstone, siltstone, and slate. The ore bodies are typically layer- or lens-like in shape and generally extend parallel to the stratification of the host sedimentary rocks, with a strike length of tens to several hundreds of meters. The immediate host rocks consist mainly of calcareous slate and siltstone characterized by high contents of organic matter and diagenetic pyrite. The main primary ore minerals associated with gold mineralization include pyrite, arsenopyrite, realgar, and stibnite. Gangue minerals comprise mostly quartz, calcite and dolomite. Gold is extremely fine-grained, usually less than 1 μm, and cannot be seen with an electron microscope.Two types of ore mineralization have been recognized in the deposits. The stratiform ores are composed of rhythmical interbeds of sulfides (e.g., pyrite, arsenopyrite, realgar, stibnite) interpreted to be authigenic and detrital quartz, quartzite, sericite, and graphite of allogenic origin. They were folded and deformed concordantly with host rocks, and grade both vertically and laterally into normal country rocks. Another type of ore forms a network of numerous gold-bearing veins and veinlets of quartz–calcite–sulfides of millimeter-, centimeter-, decimeter-, and even meter-scale in width. The network ore randomly fills fissures, microfissures, and cleavages, but still is stratabound in character. Detailed studies on ore fabrics show abundant evidence for synsedimentary origins, although subsequent diagenesis, metamorphism, tectonic deformation, and epigenetic hydrothermal activity have significantly remolded the primary fabrics. Primary fabrics are shown either by rhythmical interbeds of different mineral components parallel to the bedding, or by the change of grain size of the same minerals such as pyrite, realgar, and stibnite. The layer inhomogeneity of the stratiform ore is clarified by parallel overprints of later schistosity planes, resulting in distinct grain orientation and elongation, aggregate polarization, and undulating extinction of ore minerals, especially of mechanically and chemically extremely mobile ones, such as realgar and stibnite.It is proposed that the stratiform ores in these Chinese deposits were most probably formed concurrently with their host Middle–Upper Triassic turbidites in submarine, hot spring environments, while the network mineralization was formed as a result of complicated processes such as diagenesis, weak metamorphism, tectonic deformation, and epigenetic hydrothermal activity, responsible for the remobilization or reworking of the pre-existing stratiform ores. Geochemical data also support this genetic model. 相似文献
13.
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
14.
康滇古大陆裂谷的发生和演化造就了楚雄盆地,沉积出煤、铜、盐旋回与含矿建造和矿床组合.铜矿的生成(特别是改造富集)与煤(有机质)、盐(热卤水)密切相关.大姚—牟定式砂岩铜矿以其规模最大而具代表性.它的成矿作用的演化是从风化沉积作用到成岩作用、后生作用再到改造作用.作用的结果是分别产生含铜有机质沉积体、成岩矿层、后生矿层和改造富矿体.层状矿体赋存于砂岩浅紫交互带是氧化性流体与还原性流体相汇于斯而发生氧化—还原反应沉积成岩的结果.其金属硫化物的生成顺序与分带是遵循S、O、Fe、Cu热液体系中矿物共生组合规律的,随介质条件、四元素浓度的差异而变化. 相似文献
15.
TECTONIC SETTING AND METALLOGENESIS OF THE PRINCIPAL SECTORS OF THE TETHYAN EURASIAN METALLOGENIC BELT 总被引：1，自引：0，他引：1
Slobodan Jankovic 《大地构造与成矿学(英文版)》2001,25(1)
Three global metallogenic belts were formed in the world during Mesozoic and post-Mesozoic times. Two of them are situated along the western and eastern Pacific margins, and the third one - the Tethyan Eurasian metallogenic belt (TEMB) is related to the domain of Eurasian plate and flanked on the south by the Afro-Arabian and Indian plates. The general tectonic evolution of the realm where the TEMB was formed is closely connected with the history of Tethys. The emplacement of ore deposits and the development of regional metallogenic units are related to a definitive time interval and to specific tectonic settings such as: (1) Intracontinental rifting along the northern margin of Gondwana and/or fragments already separated; (2) Oceanic environments (i.e. ophiolite complexes and ocean floor sediments) host podiform chromite deposits, volcano-sedimentary cupriferous pyrite deposits (Cyprus type), stratiform manganese deposits, and sporadically PGE deposits; (3) Subduction related settings involve mainly porphyry copper deposits, hydrothermal massive sulphide polymetallic deposits, and epithermal deposits. So far identified mineralization of porphyry copper exceeds in the TEMB over 100 million tons of copper metal; and(4) Collision and post-collision continent-continent setting includes deposits of lead-zinc, antimony, gold, in some sectors tin deposits, as well. The giant deposits of Li-pegmatite occur sporadically.The TEMB is almost a continuously mineralized belt, but within it, some sectors display specific features of tectonic settings, association of elements, minerals and morphogenetic types of mineralization. 相似文献
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碎屑沉积的粒度研究,已有七十余年历史。近二十年来,无论分析方法及资料解释,都有长足进步,因而已经成为岩石定量研究和环境(相)推断方面的重要手段。 相似文献
18.
根据铜矿床的成因类型,对全国177个铜矿床的自然重砂矿物进行统计分析。结果显示,自然重砂矿物对于铜矿床成因类型具有较好的指示意义。不同成因类型铜矿床的自然重砂矿物组合不同,尤其是岩浆型、斑岩型、矽卡岩型、火山岩型铜矿床均具有特征自然重砂指示矿物。除了铜矿物、铅锌矿物、黄铁矿、白钨矿等各类型铜矿床共有自然重砂矿物外,铬铁矿、镍黄铁矿、辉石、橄榄石等为岩浆型铜矿床的特征指示矿物,自然金、辉钼矿、磷灰石、磷钇矿等可以指示斑岩型铜矿床;锆石、锡石和石榴子石是矽卡岩型铜矿床的特征指示矿物;火山岩型铜矿床则以雄黄、雌黄作为特征指示矿物。这些研究对于建立不同成因类型铜矿的自然重砂找矿模型具有重要意义。 相似文献
19.
Copper and uranium may be closely associated metals in sedimentary basins in which “upstream” sediments have been diagenetically reddened (e.g., sediment-hosted stratiform copper (SSC) deposits and roll-type uranium deposits) and the immediate hosts of mineralization are adjacent reduced sediments. The timing of leaching is closely linked to the process and timing of reddening, with descending meteoric water providing the oxygen needed for the reddening process. To leach and transport copper, the low-temperature pore solution must evolve to a brine, and importantly, its Eh must decrease to moderately positive levels (0.1 ± 0.1 V). For uranium, a simple oxidized solution is sufficient. Given the parallel Eh paths for copper and uranium and their close associations with diagenetic reddening, the dominant metal in sediment-hosted stratiform copper or roll-type uranium deposits is probably related closely to the source mineral and/or rock constituents of the reddened sediments. 相似文献