Tectonic Units and Their Fundamental Characteristics on the Northern Margin of the Alxa Block1

Abstract The northern margin of the Alxa block is the junction of a tectonic units. Four first—order tectonic units are distinguished: 1. the Yagan structural zone characteristic of an immature island arc; 2. the Zhusileng—Hangwula structural zone, which was a passive continental margin in the Early Palaeozoic and was transformed into an active continental margin in the Late Palaeozoic; 3. the Shalazha structural zone characteristic of a mature island arc; 4. the Nuru—Langshan structural zone, which was a Proterozoic orogenic belt and later evolved into an extensional transitional crust in the Palaeozoic. The above—mentioned tectonic units differ remarkably in sedimentary formations, magmatic rock associations, metamorphism and geochemistry and are bounded by faults between one another.     

Palaeozoic collisional tectonics and magmatism of the Chinese Tien Shan, central Asia

The Chinese Tien Shan range is a Palaeozoic orogenic belt which contains two collision zones. The older, southern collision accreted a north-facing passive continental margin on the north side of the Tarim Block to an active continental margin on the south side of an elongate continental tract, the Central Tien Shan. Collision occurred along the Qinbulak-Qawabulak Fault (Southern Tien Shan suture). The time of the collision is poorly constrained, but was probably in in the Late Devonian-Early Carboniferous. We propose this age because of a major disconformity at this time along the north side of the Tarim Block, and because the Youshugou ophiolite is imbricated with Middle Devonian sediments. A younger, probably Late Carboniferous-Early Permian collision along the North Tien Shan Fault (Northern Tien Shan suture) accreted the northern side of the Central Tien Shan to an island arc which lay to its north, the North Tien Shan arc. This collision is bracketed by the Middle Carboniferous termination of arc magmatism and the appearance of Late Carboniferous or Early Permian elastics in a foreland basin developed over the extinct arc. Thrust sheets generated by the collision are proposed as the tectonic load responsible for the subsidence of this basin. Post-collisional, but Palaeozoic, dextral shear occurred along the northern suture zone, this was accompanied by the intrusion of basic and acidic magmas in the Central Tien Shan. Late Palaeozoic basic igneous rocks from all three lithospheric blocks represented in the Tien Shan possess chemical characteristics associated with generation in supra-subduction zone environments, even though many post-date one or both collisions. Rocks from each block also possess distinctive trace element chemistries, which supports the three-fold structural division of the orogenic belt. It is unclear whether the chemical differences represent different source characteristics, or are due to different episodes of magmatism being juxtaposed by later dextral strike-slip fault motions. Because the southern collision zone in the Tien Shan is the older of the two, the Tarim Block sensu stricto collided not with the Eurasian landmass, but with a continental block which was itself separated from Eurasia by at least one ocean. The destruction of this ocean in Late Carboniferous-Early Permian times represented the final elimination of all oceanic basins from this part of central Asia.     

Detrital zircon ages in Palaeozoic and Mesozoic basement assemblages of the Peninsular Ranges batholith,Baja California,Mexico: constraints for depositional ages and provenance

The origin and continuity of Phanerozoic lithostratigraphic terranes in southern and Baja California remain an unsolved issue in Cordilleran tectonics. We present data from eight detrital zircon samples collected across the southern extent of the Peninsular Ranges that help constrain the provenance of detritus and the depositional ages of these basement units. Detrital zircon signatures from units in the eastern Peninsular Ranges correlate with Palaeozoic passive margin assemblages in the southwestern North American Cordillera. Units in the central belt, which consists of Triassic–Jurassic metasedimentary turbidite assemblages that probably deformed in an accretionary prism setting, and Cretaceous metasedimentary and metavolcanic units that represent the remnants of a continental margin arc, were derived from both proximal and more distal sources. The westernmost units, which are locally structurally interleaved with the Triassic through Cretaceous units of the central belt, are Cretaceous deposits that represent a series of collapsed basin complexes located within and flanking the Cretaceous Alisitos volcanic island arc. Cretaceous intra-arc units show little influx of cratonal material until approximately 110 Ma, whereas coeval sediments on the northern and eastern flanks of the Alisitos arc contain abundant cratonal detritus. Intra-arc strata younger than approximately 110 Ma contain large amounts of Proterozoic and older detrital zircons. These data suggest that basins associated with the Alisitos arc were either too distant or somehow shielded from North American detritus before 110 Ma. In the case of the former, increased influx of continental detritus after 110 Ma would support a tectonic model in which the arc was separated from North America by an ocean basin and, as the arc approached the continent, associated depositional centres were close enough to receive input from continental sources.     

中甸晚三叠世图姆沟组岩石化学与构造环境

本文对中甸东部晚三叠世图姆沟组深水浊积岩和弧火山岩、微量和稀土元素进行研究,投点多落入再旋回造山带物源区;微量和稀土元素与图解中多接近大陆岛弧区;常量元素分析与相关图解接近活动大陆边缘和大陆岛弧环境,与火山岩的大地构造环境具有相同的结论。图姆沟组为甘孜—理塘洋盆向西俯冲消减,中甸褶皱带东缘由被动大陆边缘转化为活动大陆边缘过程中形成的岛弧火山—沉积岩系。     

甘肃北山地区基本构造格局和成矿系列特征

甘肃北山地区并不存在具分割洋-陆板块构造意义的缝合带或蛇绿岩带,主体由东天山和塔里木两大古陆系统构成。两大古陆系统的碰撞拼合带或界线大体位于方山口—黑山—碱泉子一线,以北归属东天山古陆系统,以南归属于塔里木古陆系统。按其内的地层时代、沉积建造、岩浆作用、地壳结构等特征,可将东天山古陆系统从北往南划分为北山岛弧带、北山(白山)晚古生代弧后盆地裂陷（谷）带和北山中央古陆断隆带3个Ⅱ级结构单元,空间上三者构成一个从岛弧—弧后盆地—前陆基底带的洋-陆过渡性的地壳结构。南侧的塔里木古陆系统则经历了初始陆核向成熟陆壳发展演化的地史过程,按不同地段的地壳结构和构造作用特征将其划分为（从北往南）塔里木古陆陆缘早古生代裂陷带、红柳园-大奇山-天仓古生代多旋回裂谷带和塔里木前陆基底带3个Ⅱ级构造单元。在此基础上,根据相关的成矿响应特征综述了不同构造单元的成矿系列。     

中国东南大陆边缘若干问题的认识

中国东南大陆边缘自元古宙以来就以沟-弧-盆形式向洋增生扩张。浙闽变质带属于震旦纪至早古生代岛弧。华南地槽区是在这一时期由扩张作用形成的弧后盆地。这一沟弧盆系统在加里东期褶皱变质,与大陆拼贴。在晚古生代,沿海地区有新的扩张带形成。周期性的扩张和挤压是中国东南大陆边缘地壳演化的特征。     

Tectonics of the Caucasus and adjoining regions: implications for the evolution of the Tethys ocean

The evolution of Tethys is analysed on the basis of ophiolitic geology, reconstruction of continental margins, and plate kinematics. The North Anatolian-Minor Caucasian-South Caspian ophiolitic belt is considered to be the major suture of Palaeozoic Tethys, dividing its southern carbonate shelf from the Pontian-Caucasian-Turanian active margin. The Caucasian part of the latter comprises the Transcaucasian island arc, the Great Caucasian small ocean basin, the Great Caucasian island arc and the Precaucasian marginal sea, each characterised by its own magmatic, metamorphic and sedimentary facies association typical of that tectonic environments. The North Anatolian branch of Tethys persisted throughout the Palaeozoic and Mesozoic, whereas eastwards the major oceanic tract shifted south into the Zagros zone.The Northern frame of Mesotethys comprises the Pontain-Caucasian and Nakhichevan-Iranian island arc systems, divided by the Minor Caucasian basin, a relict of Palaeotethys reduced to a narrow northern branch of the Mesozoic ocean. In the late Cretacaous-Palaeogene, the youngest southwestern branch of Tethys separated Taurus-Anatolia from the Arabian shelf. Its ‘old’ northern branches were closed in the Palaeogene. Northward subduction in the South Anatolia-Zagros intracontinental basin triggered Neogene calc-alkaline volcanism in the Pontides, Antolia, Caucasus and Iran.     

甘肃北山地区基本构造格局和成矿系列特征

甘肃北山地区并不存在具分割洋-陆板块构造意义的缝合带或蛇绿岩带,主体由东天山和塔里木两大古陆系统构成。两大古陆系统的碰撞拼合带或界线大体位于方山口—黑山—碱泉子一线,以北归属东天山古陆系统,以南归属于塔里木古陆系统。按其内的地层时代、沉积建造、岩浆作用、地壳结构等特征,可将东天山古陆系统从北往南划分为北山岛弧带、北山（白山）晚古生代弧后盆地裂陷（谷）带和北山中央古陆断隆带3个Ⅱ级结构单元,空间上三者构成一个从岛弧—弧后盆地—前陆基底带的洋-陆过渡性的地壳结构。南侧的塔里木古陆系统则经历了初始陆核向成熟陆壳发展演化的地史过程,按不同地段的地壳结构和构造作用特征将其划分为（从北往南）塔里木古陆陆缘早古生代裂陷带、红柳园-大奇山-天仓古生代多旋回裂谷带和塔里木前陆基底带3个Ⅱ级构造单元。在此基础上,根据相关的成矿响应特征综述了不同构造单元的成矿系列。     

西藏当雄纳龙晚古生代裂谷盆地的识别及其意义

西藏冈底斯构造带是冈瓦纳大陆北部边缘的重要组成部分，经历了特提斯演化的全过程，并在中生代发育的典型的多岛弧－盆地系统。笔者根据冈底斯构造带中部纳龙地区晚古生代发育的沉积相类型、火山岩组合以及古生物等方面的资料，首次提出当雄纳龙盆地在中二叠世栖霞期具有裂谷盆地性质，揭示出冈底斯地区在二叠纪已转化为活动大陆边缘，为研究西藏冈底斯地区弧－盆系统的形成过程及晚古生代的区域构造特征古地理格局提供了重要的资料。     

Geology and geodynamic evolution of the high-P/low-T Maksyutov Complex, southern Urals, Russia

The high-pressure/low-temperature Maksyutov Complex is situated in the southern Urals between the Silurian/Devonian Magnitogorsk island arc and the East European Platform. The elongated N-S-trending complex is made up of two contrasting tectono-metamorphic units. Unit 1 consists of a thick pile of Proterozoic clastic sediments suggested to represent the passive margin of the East European Platform. The overlying unit 2, composed of Paleozoic sediments, volcanic rocks, and a serpentinite mélange with rodingites, is interpreted as a remnant of the Uralian Paleo-ocean. Devonian eastward subduction of oceanic crust beneath the Magnitogorsk island arc resulted in an incipient blueschist-facies metamorphism of unit 2 indicated by lawsonite pseudomorphs in the rodingites. While unit 2 was accreted to the upper plate, subduction of the continental passive margin caused the high-pressure metamorphism of unit 1. Buoyancy-driven exhumation of unit 1 into the forearc region led to its juxtaposition with unit 2 along a retrograde top-to-the-ENE shear zone. Further exhumation of the Maksyutov Complex into its present tectonic position was accomplished by later shear zones that were active as normal faults and are exposed along the margins of the complex. At the western margin a top-to-the-west shear zone juxtaposed a low-grade remnant of a Paleozoic accretionary prism (Suvanyak Complex) above the Maksyutov Complex. Along the eastern margin a top-to-the-east shear zone and the brittle Main Uralian Normal Fault emplaced the Maksyutov Complex against the Magnitogorsk island arc in the hanging wall.     

拉脊山蛇绿混杂带结构组成、形成时代与形成过程

祁连造山带是原特提斯洋闭合过程中, 阿拉善和柴达木地块在青藏高原东北缘拼合的产物。它是由蛇绿岩残片、海山、岛弧、弧前/弧后盆地等多个构造单元构成的典型增生型造山带, 表现出在多个元古代微陆块周围分布有蛇绿岩和岛弧火山岩的特征。蛇绿混杂带广泛分布于北祁连和南祁连中, 在南祁连主要出露寒武纪玄武岩、安山岩、辉长岩、超基性堆晶岩、硅质岩、灰岩、砂岩和少量地幔橄榄岩, 呈现出蛇绿混杂带的典型特征, 其中拉脊山蛇绿混杂带是该蛇绿混杂带的最大组成部分。因此, 拉脊山蛇绿混杂带的来源和形成构造背景对研究祁连造山带构造演化具有重要的意义。由于构造的复杂性以及系统的野外和岩石学方面研究的缺乏, 拉脊山蛇绿混杂带的岩石组合、同位素年龄和构造背景仍然不清楚, 从而严重制约了区域构造演化的认识。例如, 前人根据灰岩中三叶虫化石将拉脊山地区火山-沉积岩系划归于寒武纪, 然而其它岩石单元的同位素年龄和来源信息相对缺乏, 而且灰岩究竟是本地岩块还是老的异地岩块仍有待进一步研究。岩石地球化学分析结果显示表明寒武纪玄武岩具有MORB、WPB或者OIB的特征, 且部分玄武岩具有岛弧亲缘性。因此, 大陆裂谷、弧后盆地、多阶段抬升构造窗或俯冲-增生杂岩等模式相继被提出。这些分歧严重影响了我们对祁连造山带和原特提斯洋构造演化的认识。究其根本原因, 是由于缺乏将蛇绿岩和岛弧形成视为沟-弧-盆体系演化过程中一个具有成因联系的有机体对其进行综合分析。     

TECTONICS OF THE DABIE OROGENIC BELT, CENTRAL CHINA

Tectonically the Dabie orogenic belt consists mainly of the Dabieshan Yanshanian uplifted zone and the Beihuaiyang Variscan-Indosinian folding zone. In the north boundary adjoining the North China Block, there are an Early Palaeozoic ophiolitic mixtite belt and the Hefei Mesozoic-Cenozoic faulted basin which overlaps on the suture belt. In the south of Dabie orogen, there is a secondary tectonic unit called Foreland thrust-faulted structural zone which was mainly formed by the intracontinental subductions during Mesozoic era. The study shows that the Dabie Block is a part of mid-late Proterozoic palaeo-island arc at the north margin of Yangtze Block. During Caledonian period, as a submerged uplift at the northen continental margin of Yangtze Block, the Dabie Block collided with the early Palaeozoic palaeo-island arc at the south margin of North China Block, resulting in the convergence of the North and South China Blocks and the disappearance of oceanic crust. Since then,large-scale intracontinental subductions were followed. Dabie Orogenic Belt is the product of overlapping of Yangtze Block, Dabie Block and North China Block under the mechanism of intracontinental subduction. Indosinian period is the period of chief deformation and high pressure dynamic metamorphism for Dabie Block, and Yanshan period is the main orogenic period in which the remelting of crust caused by basement shearing resulted in large scale thermometamorphism. The present tectonic framework of the orogen was finally formed by the rapid uplifting of the Dabieshan mountains and gliding southwards, which result in the developing of thrust belt on south side and the extensional tectonic movement on north side.     

TECTONICS OF THE DABIE OROGENIC BELT, CENTRAL CHINA

Tectonically the Dabie orogenic belt consists mainly of the Dabieshan Yanshanian uplifted zone and the Beihuaiyang Variscan-Indosinian folding zone. In the north boundary adjoining the North China Block, there are an Early Palaeozoic ophiolitic mixtite belt and the Hefei Mesozoic-Cenozoic faulted basin which overlaps on the suture belt. In the south of Dabie orogen, there is a secondary tectonic unit called Foreland thrust-faulted structural zone which was mainly formed by the intracontinental subductions during Mesozoic era. The study shows that the Dabie Block is a part of mid-late Proterozoic palaeo-island arc at the north margin of Yangtze Block. During Caledonian period, as a submerged uplift at the northen continental margin of Yangtze Block, the Dabie Block collided with the early Palaeozoic palaeo-island arc at the south margin of North China Block, resulting in the convergence of the North and South China Blocks and the disappearance of oceanic crust. Since then,large-scale intracontinental subductions were followed. Dabie Orogenic Belt is the product of overlapping of Yangtze Block, Dabie Block and North China Block under the mechanism of intracontinental subduction. Indosinian period is the period of chief deformation and high pressure dynamic metamorphism for Dabie Block, and Yanshan period is the main orogenic period in which the remelting of crust caused by basement shearing resulted in large scale thermometamorphism. The present tectonic framework of the orogen was finally formed by the rapid uplifting of the Dabieshan mountains and gliding southwards, which result in the developing of thrust belt on south side and the extensional tectonic movement on north side.     

Regional metamorphism and tectonic evolution of the Inner Mongolian suture zone

Abstract Regional metamorphism in central Inner Mongolia has occurred during four different periods: the middle Proterozoic, the early Palaeozoic, the middle Palaeozoic and the late Palaeozoic tectonic cycles. The middle Proterozoic and late Palaeozoic metamorphic events are associated with rifting and are characterized by low-pressure facies series. The early Palaeozoic metamorphism occurred in two stages: (1) subduction zone metamorphism resulted in paired metamorphic belts in the Ondor Sum ophiolite and Bainaimiao island arc complex; and (2) orogenic metamorphism occurred during the collision of an island arc with the continent. Two types of middle Palaeozoic metamorphism are represented: (1) subduction zone metamorphism, which affected the melange; and (2) orogenic metamorphism that resulted from continent–continent collision.     

东秦岭二郎坪弧后盆地双向式俯冲特征

二郎坪弧后盆地是北秦岭早生古代活动大陆边缘沟－弧－盆系统的重要组成部分,现今二郎坪岩群是古弧后盆地的物质残存,记录了盆地演化方式和过程,沉积建造和岩浆作用研究发同,在二郎坪弧后盆地南北两侧各发育一套活动型陆缘沉积体系和一系列府冲型花岗岩,变形构造解析反映出主造山期早期沿弧后盆地两侧各形成一套韧性推覆构造系,并具对冲型几何学样式,为俯冲带典型构造,综合分析表明,弧后盆地在造山早期分别俯冲于南部秦岭古岛弧和北部宽坪古陆之下,具双向式俯冲特征。     

Trace element characteristics of graywackes and tectonic setting discrimination of sedimentary basins

The graywackes of Paleozoic turbidite sequences of eastern Australia show a large variation in their trace element characteristics, which reflect distinct provenance types and tectonic settings for various suites. The tectonic settings recognised are oceanic island arc, continental island arc, active continental margin, and passive margins. Immobile trace elements, e.g. La, Ce, Nd, Th, Zr, Nb, Y, Sc and Co are very useful in tectonic setting discrimination. In general, there is a systematic increase in light rare earth elements (La, Ce, Nd), Th, Nb and the Ba/Sr, Rb/Sr, La/Y and Ni/Co ratios and a decrease in V, Sc and the Ba/Rb, K/Th and K/U ratios in graywackes from oceanic island arc to continental island arc to active continental margin to passive margin settings. On the basis of graywacke geochemistry, the optimum discrimination of the tectonic settings of sedimentary basins is achieved by La-Th, La-Th-Sc, Ti/Zr-La/Sc, La/Y-Sc/Cr, Th-Sc-Zr/10 and Th-Co-Zr/10 plots. The analysed oceanic island arc graywackes are characterised by extremely low abundances of La, Th, U, Zr, Nb; low Th/U and high La/Sc, La/Th, Ti/Zr, Zr/Th ratios. The studied graywackes of the continental island arc type setting are characterised by increased abundances of La, Th, U, Zr and Nb, and can be identified by the La-Th-Sc and La/Sc versus Ti/Zr plots. Active continental margin and passive margin graywackes are discriminated by the Th-Sc-Zr/10 and Th-Co-Zr/10 plots and associated parameters (e.g. Th/Zr, Th/Sc). The most important characteristic of the analysed passive margin type graywackes is the increased abundance of Zr, high Zr/Th and lower Ba, Rb, Sr and Ti/Zr ratio compared to the active continental margin graywackes.     

初论苏门答腊（印尼）的岩浆一构造旋回及其板块构造背景

本文将晚古生代以来苏门答腊火成岩划分出四个岩浆-构造旋回或岩浆活动期次（海西期、印支期、燕山期和喜山期）,并讨论其板块构造背景。结果表明：分布于西苏门答腊地体海西期酸性侵入岩属于碰撞后地壳的火山弧I-型花岗岩带,其火山岩为大陆拉张带（初始裂谷）中的安山．玄武岩系列,而分布在东苏门答腊地体的大多数酸性侵入岩具有s-型花岗岩的性质。印支期西苏门答腊地体侵入岩为I-型花岗岩,属于火山弧花岗岩。印支期碰撞后板内岩浆活动带（廖内群岛-班加岛-勿里洞岛）的侵入岩以含锡s-型花岗岩为特色。燕山期以后的深成岩-火山岩活动的岩石类型和分布特征,受大陆拉张带（初始裂谷）及其相邻的洋岛的控制。燕山早期细碧岩属于陆缘裂谷火山岩。喜山期火山岩属于陆缘火山弧,其中橄榄玄粗岩落在洋岛玄武岩与洋中脊玄武岩（MORB）交界线附近。     

大地构造对上扬子区志留纪生物礁分布及发育的控制

根据上扬子板块的基底特征，及板块边缘特征等不同大地构造单元演化特征入手，分别对上扬子板块基底地貌、板块边缘构造及板内不同构造单元控制志留纪古沉积环境及生物礁发育演化进行了论述。在上扬子板块的北缘（南秦岭构造带），为被动大陆边缘，沉积环境适于生物礁发育，类型较多。而板块西缘（金沙江构造带）为主动大陆边缘，在岛弧区发育部分点礁以及生物层；板块内部受古隆起影响的地区（川西北、川东南、黔北），形成缓坡沉积环境，在浅缓坡区生物礁十分发育，类型众多；但是板内深断裂（龙门山，二郎山-攀西裂谷带）边缘生物礁不甚发育，仅见生物层-小型点礁组合。志留纪时，上扬子板块受全球海平面变化的影响明显，至Ｗｅｎｌｏｃｋ期后，大部分地区因海平面下降而无沉积。但是在板块边缘凹陷区，因区域构造的影响，全球海平面波动对其影响不大，Ｗｅｎｌｏｃｋ期后继续接受沉积且发育生物礁。     

The origin of the Woyla Terranes in Sumatra and the Late Mesozoic evolution of the Sundaland margin

The Jurassic–Cretaceous Woyla Group of northern Sumatra includes fragments of volcanic arcs and an imbricated oceanic assemblage. The arc rocks are intruded by a granitic batholith and are separated from the original continental margin of Sundaland by the oceanic assemblage. Rocks of the arc assemblage are considered to be underlain by a continental basement because of the occurrence of the intrusive granite and of tin anomalies identified in stream sediments. Quartzose sediments associated with the granite have been correlated with units in the Palaeozoic basement of Sumatra. From these relationships a model has been proposed in which a continental sliver was separated from the margin of Sundaland in the Late Jurassic to Early Cretaceous in an extensional strike-slip faulting regime, producing a short-lived marginal basin. The separated continental fragments have been designated the Sikuleh and Natal microcontinents. In the mid-Cretaceous the extensional regime was succeeded by compression, crushing the continental fragments back against the Sundaland margin, with the destruction of the marginal basin, now represented only by the imbricated oceanic assemblage. Modifications of this scenario are required by subsequent studies. Age-dating of the volcanic assemblage and intrusive granites in the Natal area showed that they formed part of an Eocene–Oligocene volcanic arc and are not relevant to the model. Thick-bedded radiolarian chert and palaeontological studies in the oceanic Woyla Group rocks of the Natal and Padang areas showed that they formed part of a more extensive and long-lived ocean basin which lasted from at least Triassic until mid-Cretaceous. This raised the possibility that the Sikuleh microcontinent might be allochthonous to Sumatra and encouraged plate tectonic reconstructions in which the Sikuleh microcontinent originated on the northern margin of Gondwanaland and migrated northwards across Tethys before colliding with Sundaland. Since these models were proposed, the whole of Sumatra has been mapped and units correlated with the Woyla Group have been recognised throughout western Sumatra. These units are reviewed and the validity of their correlation with the Woyla Group of northern Sumatra is assessed. From this review a revised synthesis for the Late Mesozoic tectonic evolution of the southwestern margin of Sundaland is proposed.     

祁连山新元古代——早古生代火山作用与铁-铜多金属成矿

祁连山造山带新元古代—早古生代是板块构造演化与成矿的最重要时段,铁、铜多金属矿产资源丰富,成矿作用与新元古代—早古生代火山作用密切相关。根据矿床产出构造位置,将祁连山铁、铜多金属矿床分为4类:大陆裂谷型铁(铜)矿床、岛弧-岛弧裂谷型铜多金属矿床、陆缘裂谷型铜多金属矿床、扩张脊型铜矿床。镜铁山铁(铜)型矿床是新元古代大陆裂谷火山作用过程中热水沉积作用的产物;东沟铜矿为晚寒武世大洋扩张脊火山作用的产物;白银矿田铜多属矿床是奥陶纪与岛弧-岛弧裂谷火山作用的产物;石居里铜矿是晚奥陶纪弧后扩张脊有关火山作用的产物;红沟铜矿则是晚奥陶世陆缘裂谷火山作用的产物。