| 克拉通和古生代造山带中的韧性剪切带型金矿：金矿成矿条件与成矿环境分析 |
| 点此下载全文 |
| 引用本文：.2004.Ductile-Shear Zone Related Gold Deposits in Craton and Paleozoic Orogenic Belt: An Analysis of Their Ore-forming Processes and Environments[J].Mineral Deposits,23(4):509~519 |
| Hits: 2992 |
| Download times: 2713 |
|
| 基金项目:国家重点基础研究发展规划项目“中国西部中亚型造山与成矿”课题(编号：200 1CB409807) |
|
| 中文摘要:文章总结了产在克拉通和古生代造山带中、受韧性剪切带控制的金矿 的重要研究成果。通过对比这两类金矿的地质特征及其成矿作用发生的大地构造背景，探讨 形成韧性剪切带型金矿的成矿环境与成矿机制。大型韧性剪切带型金矿一般就位于剪切带的 脆_韧性转换位置，成矿作用一般不受围岩性质和变质程度的控制。剪切带既是成矿流体的 通道，又是金的沉淀场所。克拉通中韧性剪切带型金矿的成矿模式有两类：同构造成矿和构 造期后成矿，前者认为变质流体沿韧性剪切带迁移，最终在剪切带中沉淀形成矿床；后者则 强调发生在韧性剪切带形成之后的地质过程如岩浆活动等对成矿作用的贡献。 |
| 中文关键词:地质学 韧性剪切带 金矿 太古宙克拉通 古生代造山带 综述 |
| |
| Ductile-Shear Zone Related Gold Deposits in Craton and Paleozoic Orogenic Belt: An Analysis of Their Ore-forming Processes and Environments |
|
|
| Abstract:The large_size shear zone related gold deposits are usually located in the trans itional part from ductile to brittle deformation. The shear zones served as path s for fluid migration as well as places for gold deposition. The ore_forming pro cesses were not necessarily related to the host rocks and their metamorphic faci es. Two models for the ductile_shear zone related gold deposits in old cratons h ave been proposed, namely the syntectonic model and the post_tectonic model. The former model believes that metamorphic fluids migrated along the shear zones an d ultimately deposited gold. The latter model, however, holds that the ore_formi ng processes related to the geological events took place after the formation of shear zones. In such cases, shear zones served as the fluid pathway and the host of gold deposits. Magmatism played a significant role in some deposits, while i n other cases gold formation was not related to any magmatism although granitic bodies might have served as wall rocks of gold_bearing veins. In both cases, the gold_bearing veins mainly occurred in the second_order fractures related to the major shear zones，and the host rocks exerted insignificant effects on the ore_ forming processes. The ductile_shear zone related gold deposits in Paleozoic oro genic belt generally had close relations with the evolution of the orogenic belt . The huge Central Asian orogenic belt (including Urals and Tianshan) has comple x evolutionary histories, subjected to oceanic crust subduction, formation of is land arcs, and continental collisions. This complex orogenic belt is famous for its numerous world_class ductile_shear zone related gold deposits. There is no principal difference between these two types of shear_zone related g old deposits in their modes of occurrence and mineral assemblages. However, they differ apparently from each other in ore_forming mechanism, ore_forming environ ments, and sources of ore_forming fluids. The shear_zone related gold deposits i n the orogenic belt actually resulted from the orogenic process at a definite st age. The ore_forming materials were usually characterized by diversification and might include materials from Lower to Middle crust and upper mantle. The Tiange er_Wangfeng gold deposit in Middle Tianshan was formed in the Late Paleozoic oro genic belt, occurring as a stage_product in the orogenic processes of the Tiansh an Mountains. The shear_zone served as the channel for fluid migration. When gol d_bearing ore_forming super_critical fluids moved from the lower crust to shallo w levels, the decrease of gold solubility caused gold deposition and thus formed gold deposits. |
| keywords:geology, ductile_shear zone, gold deposit, Archean craton, Paleozoic orogenic belt |
| View Full Text View/Add Comment Download reader |
