| 魏 浩.非洲东北部阿拉伯-努比亚地盾(ANS)构造演化与金成矿作用[J].地质与勘探,2015,51(2):283-394 |
| 非洲东北部阿拉伯-努比亚地盾(ANS)构造演化与金成矿作用 |
| Tectonic evolution and gold mineralization in the Arabian Nubian Shield (ANS), northeastern Africa |
| 投稿时间：2014-04-22 修订日期：2015-01-06 |
| DOI： |
| 中文关键词: 阿拉伯-努比亚地盾 构造演化 洋壳俯冲 造山 金矿类型 |
| 英文关键词: Arabian Nubian Shield, tectonic evolution, ocean subduction, orogeny, gold deposit type |
| 基金项目:中国地质调查局工作项目（编号：1212011220911）：非洲东北部苏丹等国重要矿床地质背景、成矿作用和找矿潜力研究资助 |
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| 中文摘要: |
| 阿拉伯-努比亚地盾（Arabian Nubian Shield，简称ANS）是900~550Ma期间冈瓦纳超大陆汇聚过程中形成的增生造山带，这一造山过程也被称为是泛非造山运动。它记录了一个长期的造山演化历史，经历了从大洋俯冲、岛弧形成及弧后的岩浆作用到大陆板块碰撞地体的拼合，再到新生地壳的逃逸构造、走滑剪切、张性断裂一系列的构造演化过程。这个演化可以分为四个阶段：1）洋盆形成阶段（870~800Ma）；2）洋壳俯冲阶段（800~670Ma）；3）造山阶段（750~550Ma）；4）后造山阶段（550Ma~三叠纪）。其中后三个阶段都有金的富集成矿作用。洋壳俯冲阶段的金矿化主要赋存在Algoma型含铁建造层（BIF）、凝灰质变质碎屑岩，以及火山成因的块状硫化物矿床内。造山阶段的主要金矿化类型为含金石英-碳酸盐脉状金矿化、与斑岩铜矿化有关的金矿化，以及与辉长岩类岩体有关的含金石英脉状矿化。与后造山阶段有关的金矿化以少量浸染状，网脉状并伴有Sn–W–Ta–Nb矿化的石英脉为特征。目前在ANS中发现了大量金矿床或矿点，它们具有各种不同的成因类型。根据构造背景及赋矿围岩，ANS原生金矿化可以划分为三类：1）与火山沉积序列有关的金矿化，包括VMS型、浅成热液型；2）空间分布上与碳酸盐化蛇绿岩带相关的金矿化；3）与后造山或造山晚期闪长岩-花岗岩岩体或次火山岩有关的金矿化。 |
| 英文摘要: |
| The Arabian–Nubian Shield (ANS) was an accretion orogenic belt that formed during convergence between the East and West Gondwana land at end of the Wilson cycle from 900 to 500 Ma, which is called the Pan-African orogeny. ANS records a long-term history of orogenic evolution, and experienced an evolution process including ocean subduction, island arc formation, back arc magmatism, then assemblage of a series of terranes, finally the escape tectonics, slip shear and extensional faulting. The tectonic evolution can be divided into four stages: 1) ocean basin (870-800Ma); 2) ocean crust subduction (800-670Ma); 3) orogeny (750-550Ma); and 4) post-orogeny (550Ma-Triassic). Stages 2-4 are periods of gold mineralization. Gold is mainly hosted in the Algoma type BIF, tuffaceous meta-clastics and VMS deposit during stage 2. Mineralization types of stage 3 are characterized by gold-bearing quart-carbonate vein, porphyry gold mineralization related with copper and gold-bearing quart vein which is associated with gabbro. Whereas, those of stage 4 are mainly composed of disseminated and stockwork gold mineralization with less Sn–W–Ta–Nb. There are currently a large number of gold deposits which belong to different types in the ANS. According to the tectonic settings and wall rocks, the original gold mineralization in ANS can be divided into three types: 1) volcanic sedimentary gold mineralization, such as VMS, epithermal deposit; 2) gold mineralization related to the carbonate and greenstone belt; and 3) gold mineralization associated with diorite-granite plutons or their sub-intrusions. |
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