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1.
研究区位于北祁连造山带西段尕大坂矿田,区内已发现的矿床均产于北侧的大柳沟-白柳沟火山穹窿的酸性火山岩和基性火山岩的接触部位。对尕大坂矿床和郭米寺矿床地质特征的研究及矿石化学成分的分析,认为矿床具"双岩石组合",是典型的海底热水喷流沉积的标志,主要为Zn-Pb-Cu型多金属矿床,属于黑矿型。通过对矿田黑茨沟组含矿火山岩系的岩石地球化学研究,表明形成环境与弧后裂谷相似。 相似文献
2.
青海祁连县清水沟—白柳沟新元古代寒武纪大陆裂谷双峰式海相火山岩中产有Fe-S和Pb-Zn-Cu型块状硫化物矿床.这两类矿床除受所在火山岩陆壳幔源区的部分熔融程度和火山作用旋回性不同影响外,主要受产生构造位置和火山岩浆源区物性条件所控制.其中产Fe-S型矿床的石头沟-香子沟穹窿火山作用,相对形成于近裂谷扩张中心的深海环境,以低K2O钙碱性的拉斑玄武质或英安质下地壳为物源区环境;郭米寺-白柳沟穹窿的Pb-Zn-Cu型火山作用形成于远离扩张中心的陆缘弧环境,源区为一种由地幔源和壳源共同构成的混合源.在矿床成因类型方面,前者近似塞浦路斯的铜黄铁矿,后者为较典型的日本黑矿型. 相似文献
3.
主要通过清水沟-白柳沟矿田与白银厂矿田的火山岩成分、微量元素特征成矿蚀变特征、地质特征等综合分析和对比研究,从块状硫化物矿床成矿系列角度,分析和讨论了清水沟-白柳沟矿田与典型的白银厂矿田的某些相似性或可比性,以期指出清水沟-自柳沟-带进一步找矿的潜力和远景地段。结果表明,2矿田无论是在成矿时代、赋矿岩石组合方面,还是在火山机构和成矿特征等方面皆有一定的可比性。由此提出在清水沟-白柳沟地区还有发现白银厂式块状硫化物矿床的潜力,并提出尕大坂是最具找矿潜力的远景区,值得进一步投人勘查工作。 相似文献
4.
《地学前缘》2015,(4)
喀腊大湾地区地处新疆若羌县境内,在区域上位于北东向阿尔金走滑断裂北侧与东西向阿尔金北缘断裂所夹持的区域,属于红柳沟—拉配泉一级成矿带的中东段部分。研究表明,喀腊大湾地区构造控矿作用明显。首先,大地构造背景控制一级矿带的分布和位置,阿尔金断裂400km左右走滑位移量将北祁连山西段成矿带左行断错至目前位置,构成了区域上红柳沟—拉配泉一级成矿带。第二,区域构造环境控制二级矿带、矿床类型和矿种类型,喀腊大湾矿集区南带南侧岛弧构造环境控制与中酸性火山岩有关的块状硫化物矿床(类VMS型),南带北侧弧盆过渡带构造环境控制与中基性火山岩有关的铁矿床,中带盆地构造环境控制与沉积岩有关的硅铁建造型铁矿床,北带南侧蛇绿混杂岩带控制与洋壳残留(基性超基性岩)有关的铜镍矿床,北带北部碰撞变形带控制与强烈韧性韧脆性变形有关的金矿床和与岩浆侵入作用有关的热液银铅矿床。第三,构造演化不同阶段具有不同的控矿作用,主要成矿作用发生在早古生代,其中:(1)新元古代晚期—早古生代早期,红柳沟—拉配泉弧后盆地(裂谷)拉张扩张时期,主要形成与中基性火山沉积作用有关的铁矿床;(2)早古生代中期为红柳沟—拉配泉弧后盆地(裂谷)俯冲碰撞作用和最后挤压闭合,形成与中酸性岛弧火山岩有关的矿床(类VMS型)(如喀腊达坂铅锌矿和喀腊大湾铜锌矿)、与大规模韧性韧脆性变形带有关的金矿床(如大平沟金矿)和与岩浆侵入活动有关的矿床(中酸性火山岩477~488 Ma,中酸性侵入岩417~514 Ma)。第四,典型构造控矿形式有火山沉积构造控矿(铁矿、铅锌矿)、韧脆性剪切带控矿(金矿)、断裂裂隙控矿(银铅矿、铜银矿)、岩体及岩体构造控矿(铜镍矿)4种类型。 相似文献
5.
白银火山穹隆构造特征及隐伏矿预测 总被引：2，自引：0，他引：2
通过讨论白银火山穹隆的构造—地层模型,指出核部主体由前寒武系（震旦系为主）酸性火山岩—次火山岩组成;外环部分主体由寒武—奥陶系中基性—碱性火山—沉积岩系组成。二者以不整合面为界。晚期火山岩常复合于早期火山岩中,构成一向东倾伏的复合型火山穹隆体。已知矿床均产于核部。在总结白银矿床成矿模式及找矿准则的基础上,新提出位于火山穹隆东部外环部位之米心掌—大洞沟—黑石山沟一带为一有远景的隐伏矿预测区。 相似文献
6.
笔者在该文中着重表达了３方面研究成果：在陈述清水沟－白柳沟地区成矿地质背景基础上，描述了已知工业矿床的基本特征，并将其类比为两类矿床，其一为Ｚｎ－Ｐｂ－Ｃｕ型小铁山式矿床，以展布于郭密寺北火山穹隆北东和南西两侧的下柳沟、弯阳河、下沟及郭密寺矿床为代表；其二为Ｃｕ（－Ｚｎ）型白银厂式矿床，以出露在黑河古火山穹隆北翼近核部的香子沟矿床为实例。成矿前期、成矿时期，以及成矿后期地质条件的分析与概括表明，该地区与白银厂地区在海相火山岩的成岩环境─—裂谷岛弧、火山岩组合──双峰式、古火山机构类型──古火山穹隆，以及成矿机制──海底热液对流循环成矿等诸多方面都具相似性，是寻找铜多金属硫化物矿床的良好地段。提出了该区此类矿床的综合成矿模式，相信它在本地区扩大寻找小铁山式矿床和突破性寻找白银厂式矿床中具有重要指导意义和实际操作意义． 相似文献
7.
下沟古火山机构位于走廊南山南坡中寒武统火山岩带的下沟地段。该火山岩带的扁麻沟——自柳沟地带爆发相火山岩广泛发育,火山岩与火山—沉积岩呈北西西向(与区域构造线一致)条带相间分布。我们的实地调查发现,这些爆发相火山岩条带是由一系列中心式火山机构组成的火山链(图1)。以前的研究者依据火山岩岩石化学特征,判定该火山岩带的火山岩属岛弧型火山岩。我们的研究成果使这一论断具体化。事实说明,扁麻沟——白柳沟 相似文献
8.
新疆阿舍勒铜锌块状硫化物矿床成矿条件和成矿特点 总被引：3，自引：0，他引：3
阿舍勒铜锌矿床是一个典型的火山岩型块状硫化物矿床。大陆边缘裂谷带是矿床形成的大地构造环境。早中泥盆世火山活动形成了含矿的双峰式火山岩套。矿床产于近喷发间歇期的石英角斑质角砾凝灰岩中，受火山洼地和同生断裂控制。 相似文献
9.
10.
团结沟斑岩金矿床多源成因的同位素地质学证据 总被引：5，自引：0，他引：5
矿床地质特征团结沟矿床是我国著名的斑岩型金矿床.矿区内主要发育一套侏罗-白垩纪中酸性陆相火山岩及次火山岩.火山活动初期以中酸性熔岩为主,包括玄武安山岩、英安岩等;中期有次火山岩相的花岗闪长斑岩侵入,并带来该区的工业金矿化;火山活动末期以喷发活动为主,并生成各种中酸性火山碎屑岩,包括火山角砾岩、晶屑凝灰岩、凝灰质砂岩等;其底部火山岩中见有含矿斑岩体的角砾.钾氩法测定含矿斑岩体的年龄是100、102、112.6百万年,为燕山期产物.火山岩周围是元古界片岩,更远处往西15公里有混合 相似文献
11.
C. E. Nelson 《Mineralium Deposita》2000,35(6):511-525
Gold mineralization in the Pueblo Viejo district, Dominican Republic, is spatially and temporally related to a series of
Early Cretaceous volcanic domes. Separate but overlapping hydrothermal cells, centered on the domes, together deposited more
than 40 million oz. of gold, 240 million oz. of silver, 3 million tonnes of zinc, and 0.4 million tonnes of copper. Two principal
deposits (Moore and Monte Negro) and a number of smaller deposits (Cumba, Mejita, Upper Mejita, Banco V, Arroyo Hondo I and
II) have contributed ore since mining commenced in 1975. New geologic mapping has identified a series of previously unrecognized
volcanic domes that vary from andesite to dacite in composition. A dacite porphyry dome intrudes epiclastic sediments in the
Moore deposit and is surrounded by a baked contact metamorphic aureole. Crumble breccias of mixed epiclastic and pyroclastic
origin mantle andesite domes in the Monte Negro, Cumba, and Mejita deposits. Epiclastic volcanic sediments surrounding each
of the domes reflect the composition of the local source rock. Andesite domes of the Monte Negro deposit are surrounded by
andesitic volcaniclastic sediments. Epiclastic sediments surrounding a dacite porphyry dome in the Moore deposit contain detrital
quartz eyes and debris flows of dacite porphyry. A series of at least seven volcanic centers interfinger, overlap, and are
interbedded with locally derived epiclastic sediments. Field relations indicate that volcanic dome emplacement, epiclastic
sediment accumulation, hydrothermal alteration, and gold mineralization were coeval events. Domes were emplaced in a shallow
subaqueous environment on the flanks of an emergent volcanic edifice. Hydrothermal cells responsible for gold mineralization
are controlled by high-angle faults. These same faults influenced the emplacement of volcanic domes, an essential step in
the development of gold ore in the Pueblo Viejo district.
Received: 15 March 1999 / Accepted: 29 September 1999 相似文献
12.
Granite-cored domes are associated with many of the larger gold deposits of the Archaean Eastern Yilgarn Craton of Western Australia. The Scotia-Kanowna Dome is eroded to sufficiently deep levels to provide insights into the role granite-cored domes play in controlling fluid flow and gold deposition. At the centre of the Scotia-Kanowna Dome is a granite batholith, which is surrounded by outward-dipping greenstone belts and associated shear zones. This upper-crustal dome sits above mid-crustal domes, providing a series of stacked geometries favourable to focussed fluid flow. A number of small- to medium-sized gold deposits occur on the limbs and the centre of the dome, and the world-class Kanowna Belle gold mine occurs on the nose of the dome. At least three separate gold mineralising events are defined, each of regional significance, which can be correlated with other well known gold deposits of the Eastern Yilgarn Craton. 相似文献
13.
新疆伊犁晚古生代裂谷陆相火山岩型铜(银)矿的成矿规律及其找矿前景--以阿吾拉勒地区为例 总被引：2，自引：0，他引：2
伊犁晚古生代裂谷陆相火山岩型铜银矿产于碱性火山岩中,在区域上表现出层控特点,即沿着上、下二叠统过渡界面分布,且多产于火山旋回顶部层位,明显受火山穹隆、火山洼地和火山机构及其派生构造的控制。具有准斑岩型、火山沉积型、火山热液型配套的矿床类型。多以火山构造为成矿基础而构成铜银成矿集中区。其中,托斯巴火山穹隆区、阿克吐别克火山向斜区和特提达坂火山穹隆区的多矿点火山构造类型区具有最佳的找矿前景。 相似文献
14.
《International Geology Review》2012,54(7):661-674
In western Anatolia, a thick volcanic succession of andesitic to rhyolitic lavas and volcaniclastic rocks crops out extensively. On Foça Peninsula, the westernmost part of the region, a dominantly rhyolitic sequence is exposed where massive rhyolites occur as dome or domelike stubby lava flows. These rhyolite domes vertically and laterally pass into blanketing volcaniclastic sequences. The gradational boundary relations and the facies characteristics of the surrounding volcaniclastic sequences indicate that the silicic domes directly intruded a subaqueous environment and were shattered upon sudden contact with water to form hyaloclastic blankets. In and around these rhyolite domes, we have defined six different volcanic and volcaniclastic facies, consisting of: (1) massive rhyolite; (2) massive perlite; (3) hyaloclastic breccias; (4) rhyolite pumice and lithic fragment-bearing volcaniclastic rocks; (5) subaqueous welded ignimbrites; and (6) brecciated perlite. The massive rhyolite facies have distinct structures from the centers to the peripheries of the domes and stubby lava flows. Massive lava facies gradually pass into hyaloclastic breccias and massive perlite facies, indicating water-magma interaction during the emplacement. Phreatomagmatic explosive activity and doming caused the subaqueous pyroclastic flows on the flanks of the volcanic center. Welding in the upper parts of these pyroclastic flow deposits indicates the high-temperature emplacement of the pyroclastic material and relatively slow cooling caused by the cushioning effect of the gas-vapor mixture and rapid deposition of younger pyroclastic units. 相似文献
15.
Archean felsic volcanic rocks form a 2000 m thick succession stratigraphically below the Helen Iron Formation in the vicinity of the Helen Mine, Wawa, Ontario. Based on relict textures and structures, lateral and vertical facies changes, and fragment type, size and distribution, the felsic volcanic rocks have been subdivided into (a) lava flows and domes (b) hyalotuffs, (c) bedded pyroclastic flows, (d) massive pyroclastic flows, and (e) block and ash flows.Lava flows and domes are flow-banded, massive, and/or brecciated and occur throughout the stratigraphic succession. Dome/flow complexes are believed to mark the end of explosive eruptive cycles. Deposits interpreted as hyalotuffs are finely bedded and composed dominantly of ash-size material and accretionary lapilli. These deposits are interlayered with bedded pyroclastic flow deposits and probably formed from phreatomagmatic eruptions in a shallow subaqueous environment. Such eruptions led to the formation of tuff cones or rings. If these structures emerged they may have restricted the access of seawater to the eruptive vent(s), thus causing a change in eruptive style from short, explosive pulses to the establishment of an eruption column. Collapse of this column would lead to the accumulation of pyroclastic material within and on the flanks of the cone/ring structure, and to flows which move down the structure and into the sea. Bedded pyroclastic deposits in the Wawa area are thought to have formed in this manner, and are now composed of a thicker, more massive basal unit which is overlain by one or more finely bedded ash units. Based on bed thickness, fragment and crystal size, type and abundance, these deposits are further subdivided into central, proximal and distal facies.Central facies units consist of poorly graded, thick (30–80 m) basal beds composed of 23–60% lithic and 1–8% juvenile fragments. These are overlain by 1–4 thinner ash beds (2–25 cm). Proximal facies basal beds range from 2–35 m in thickness and are composed of 15–35% lithic and 4–16% juvenile fragments. Typically, lithic components are normally graded, whereas juvenile fragments are inversely graded. These basal beds are overlain by ash beds (2–14 in number) which range from 12 cm to 6 m in thickness. Distal basal beds, where present, are thin (1–2 m), and composed of 2–8% lithic and 6–21% juvenile fragments. Overlying ash beds range up to 40 in number.The climax of pyroclastic activity is represented by a thick (1000 m) sequence of massive, poorly sorted, pyroclastic flow deposits which are composed of 5–15% lithic fragments and abundant pumice. These deposits are similar to subaerial ash flows and appear to mark the rapid eruption of large volumes of material. They are overlain by felsic lavas and/or domes. Periodic collapse of the growing domes produced abundant coarse volcanic breccia. The overall volcanic environment is suggestive of caldera formation and late stage dome extrusion. 相似文献
16.
宁芜向山式黄铁矿床的地质特征和成因 总被引：2，自引：0，他引：2
向山式黄铁矿床是宁芜玢岩铁硫成矿系列的中部矿,与铁矿体紧密伴生,矿床规模大、品位较高,伴生硬石膏矿可同时开采。矿体产于宁芜早白垩世大王山组火山隆起构造的衔接部位,处于次火山岩体相对凹陷的接触蚀变带中。从硫同位素、Co/Ni 值及测温数据等判断,矿床形成具有同生沉积-火山气液双重物源,下伏含膏岩系提供了主要的硫源。 相似文献
17.
西天山吐拉苏-也里莫墩金成矿带简述 总被引：9，自引：0，他引：9
吐拉苏一也里莫墩矿带是西天山地区重要金矿成矿区.矿带内金矿赋存于晚古生代中期拉张(裂谷)环境下形成的早石炭世火山岩带内,金矿围岩为下石炭统大哈拉军山组陆相火山岩,成矿时代为早石炭世杜内-韦宪早期.矿带内金矿化可分为浅成低温热液系统(冰长石-绢云母型、硅化岩型)、斑岩型和沉积砾岩型.矿带内东、西两段控矿构造有差异:西部吐拉苏地区的阿希、京希开布拉克、伊尔曼得等金矿产于京希一阿希近南北向火山构造拗陷带内的火山机构构造系统(冰长石-绢云母型)和层间裂隙带(硅化岩型)中;东部也里莫墩地区的加特曼、铁列克特、小于赞等金矿床(点)产于吾拉斯台-郎布拉近东西向火山构造隆起带内的次火山穹丘构造系统中. 相似文献
18.
二十一站-宝兴沟( 铜) 金矿床( 点) 位于上黑龙江断陷盆地的东南部。区域地质背景及典型矿床研究表明,矿床不仅受NE 向断裂构造控制,还受其同期的岩浆岩控制。对宝兴沟金矿床的流体包裹体测试结果、矿床围岩蚀变和与火山穹窿构造间的关系等研究,表明宝兴沟金矿可能是中硫型浅成低温热液型矿床,二十一站和十五里桥( 铜) 金矿床可能是高硫型浅成低温热液型矿床( 点) 。区域地质特征、遥感解译、航磁异常及Au、Ag、Cu 化探异常分布特征显示了本区可能存在两种环境的斑岩型--浅成低温热液型成矿热液系统。在此基础上,结合铜元素化探异常和火山穹窿等特征,提出了在十五桥金矿床、二十一站铜金矿一带寻找斑岩型铜钼矿化类型,在NW、NNE 向构造带内找寻与浅成低温热液系统有关的矿床。 相似文献
19.
The Irruputuncu is an active volcano located in northern Chile within the Central Andean Volcanic Zone (CAVZ) and that has produced andesitic to trachy-andesitic magmas over the last ∼258 ± 49 ka. We report petrographical and geochemical data, new geochronological ages and for the first time a detailed geological map representing the eruptive products generated by the Irruputuncu volcano. The detailed study on the volcanic products allows us to establish a temporal evolution of the edifice. We propose that the Irruputuncu volcanic history can be divided in two stages, both dominated by effusive activity: Irruputuncu I and II. The oldest identified products that mark the beginning of Irruputuncu I are small-volume pyroclastic flow deposits generated during an explosive phase that may have been triggered by magma injection as suggested by mingling features in the clasts. This event was followed by generation of large lava flows and the edifice grew until destabilization of its SW flank through the generation of a debris avalanche, which ended Irruputuncu I. New effusive activity generated lavas flows to the NW at the beginning of Irruputuncu II. In the meantime, lava domes that grew in the summit were destabilized, as shown by two well-preserved block-and-ash flow deposits. The first phase of dome collapse, in particular, generated highly mobile pyroclastic flows that propagated up to ∼8 km from their source on gentle slopes as low as 11° in distal areas. The actual activity is characterized by deposition of sulfur and permanent gas emissions, producing a gas plume that reaches 200 m above the crater. The maximum volume of this volcanic system is of ∼4 km3, being one of the smallest active volcano of Central Andes. 相似文献