| 桂西北地区古地热场特征及其在微细粒浸染型金矿床形成中的作用 |
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| 引用本文：.1995.The paleogeothermal field fo northweatern Guangxi: Characteristics and its role in the formation of mocro-disseminated gold deposits[J].Mineral Deposits,14(1):82~88 |
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| 中文摘要:本文以右江盆地古地热场特征分析为基础，并结合岩相和构造研究的成果，提出了沉积盆地中微细粒浸染型金矿床形成的古地温控制模式：即海底火山喷发和还原的沉积环境条件对成矿物质初始富集的控制，盆地的构造深沉降引起古地温升高促使含矿流体形成、运移和圈闭，盆地的后期构造活动和抬升引起含矿流体层的破裂或降温，致使含矿流体突破、淀析成矿。 |
| 中文关键词:右江盆地 古地热场 成矿模式 浸染型金矿床 |
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| The paleogeothermal field fo northweatern Guangxi: Characteristics and its role in the formation of mocro-disseminated gold deposits |
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| Abstract:Using vitrain reflectance data, the author made a fairly systematic investigation into the paleogeothermal field characteristics of, Late Permian and Early Triassic strata beneath the major auriferous horizon of northwestern Guangxi-Middle Triassic. The results show that the Late Permian and Early Triassic strata had been under the rather high geothermal condition before the uplifting of the basin, and the paleogeotomperature could reach 250~300℃, with the existence of a high paleogeothermal gradient zone between them and Middle Triassic strata. Based on an analysis of tectonic evolution and sedimentary facies distribution in the basin, the paper describes the important role played by the paleogeothermal field in the formation of micro-disseminated gold deposit, and points out the combinational relations of gold source bed, deposits-forming bed and capping bed. On such a basis, the metallogenic mechanism of gold deposits in this area might be divided into tluee stages: j the early stage of the basin, during which regional magmatic activities and organism-rich reductive sedimentary facies created favorable conditions for the formation of the source bed; k the rapid deep subsidence stage of the basin, during which the capping bed was formed, and the temperature of the source bed gradually rose; when the subsidence reached the depth of over 4000 m, the ore-bearing hot fluids came into being and migrated, forming the closed system of the ore-bearing hot brine at the favorable positions; l the late stage of the basin: due to the uplifting of the basin and the faulting, the temperature of the ore-bearing hot brine trap got lower and lower, and breakthrough took place along the stress relief belt; as a result, ore-forming materials were unceasingly separated out, eventually leading to the formation of ore deposits. |
| keywords:Youjiang basin, paleogeothermal field, metallogenic model, disseminated gold deposit |
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