| 安徽铜陵矿集区燕山期岩浆流体系统时空结构及成矿 |
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| 引用本文：.2004.Temporal_spatial Configuration and Mineralization of Yanshanian Magmatic Fluid Systems in Tongling Ore Concentration Area, Anhui Province [J].Mineral Deposits,23(3):298~309 |
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| 基金项目:国土资源部专项研究计划(编号：20010103)、国家自然科学基金重点项目(批准号：4 0234051)和地质调查项目(编号：20010000004) |
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| 中文摘要:通过野外地质调查和同位素年代学研究，结合前人资料，建立起铜陵 地区燕山期岩浆流体系统的时空格架及岩浆活动与矿产的关系。将铜陵地区的岩浆流体系统 分为两类4个子系统。一类是与燕山期(150～133 Ma)侵入岩有关的铜陵侵入岩岩浆流体系统 ，受近东西向铜陵_南陵基底断裂控制，依据其活动时间先后和流体活动特征，可进一步划 分为早、晚2个流体子系统；另一类是与燕山晚期(122～110 Ma)繁昌盆地火山岩有关的火山 岩流体系统，受北东侧凹陷盆地控制，与“宁芜式”玢岩铁矿和金矿关系密切，包括2个子 系统。各子系统又包括不同的流体单元，流体单元是填图的基本单位。岩浆岩自身可形成独 立矿床，同时，对海西期同生沉积矿床或矿胚层叠加改造，增补铜、金等成矿物质，使层状 矿体变富，规模变大，在铜陵地区形成全球特有的大型_超大型矽卡岩型铜矿床。 |
| 中文关键词:地质学，燕山期，岩浆流体系统，时空结构，岩浆成因，铜陵 |
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| Temporal_spatial Configuration and Mineralization of Yanshanian Magmatic Fluid Systems in Tongling Ore Concentration Area, Anhui Province |
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| Abstract:Based on field investigation and isotopic chronology, in combination with the da ta available, the authors have established the spatial_temporal configuration of the magmatic fluid system and the relationship between the magmatic activity an d the mineral resources in Tongling area. The Yanshanian magmatic fluid systems are closely related to the Cu_Au mineralization in Tongling area. It is shown by geofluid mapping that the Yanshanian magmatic systems in Tongling area can be d ivided into 2 classes covering 4 subsystems. The first class is the system relat ed to the Yanshanian (150～133 Ma) intrusions and controlled by the EW_striking fundamental faults, which can be subdivided into three distinctive subsystems on the basis of time sequences and fluid system characteristics: (1) the early sta ge of the Shizishan skarn subsystem in 153～139 Ma，related to Cu_Au mineralizat ion; and (2) the late stage of the Shatanjiao porphyry subsystem in 139 Ma～133 Ma, related to Cu_Mo mineralization. The second class is the hydrothermal fluid system related to Late Yanshanian (120～110 Ma) Fanchang eruptive rocks in the s outh of the basin and controlled by the depression of the basin, which can be su bdivided into two subsystems: (3) the Kedoushan hydrothermal subsystem in the so uth of the basin, related to (Fe)_Au mineralization in Fanchang, and (4) the Jig uanshi hydrothermal subsystem related to Au (Ag) in Tongling block, which is sup erimposed on the Tongling block beyond the basin. Among these 4 subsystems, the first 2 are the most important ones in Tongling area. On the basis of mineral pa rageneses and spatial distribution of the subsystems, each subsystem can be divi ded into several fluid units, which are the basic units for mapping of the fluid s. Considering time configuration of the magmatic rocks, the high potassic calc_ alkaline intrusions are petrogenetically attributed neither to the subduction of Yangtze plate beneath the North China plate during the Indosinian nor to the su bduction of the Pacific plate underneath the Eurasian plate or geochemically to the adakites produced by thickening of the continental crust. It is held that th e Yangtze plate on the east side of the Tancheng_Lujiang fault rotated clockwise with Guangji as the hinge under the tectonic regime of the northeastward tow of the Pacific plate during the Late Jurassic, which resulted in the NE extension of the lithosphere and the corresponding “lagged_type" magmatic activities. As the extension was limited during the early stage (153～139 Ma), it was unlikely to cause the thinning of the lithosphere but could lead to the surging of the ma gma from the potential source to form “lagged_type" magmatic rocks. The further extension during the late stage (121～110 Ma) might induce the catastrophic thi nning of the lithosphere, resulting in the formation of a series of alkaline vol canic rocks in such areas as Fanchang basin. The relationship between magmatic r ocks and mineral resources suggests that, besides independently forming ore depo sits, magmatic activity could be superimposed on the Hecynian synsedimentary dep osits or protore beds. In this way, materials such as copper and gold could be a dded to these deposits or beds so as to form high_grade and large_size stratabou nd deposits and eventually form world_famous large_superlarge "skarn_type" coppe r deposits in Tongling area. |
| keywords:geology, Yanshanian, magmatic fluid system, spatial-temporal configuration, genesis of magma, Tongling |
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