Geochemistry and geochronology of the ~620 Ma gold-associated Batouri granitoids, Cameroon
Geochemistry and geochronology of the ~620 Ma gold-associated Batouri granitoids, Cameroon
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DOI：
10.1080/00206814.2014.951003
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发表时间：
2015-09
影响因子：
2.6
通讯作者：
Akwinga Victor Asaah;B. Zoheir;B. Lehmann;D. Frei;R. Burgess;C. E. Suh
中科院分区：
文献类型：
--
作者：
Akwinga Victor Asaah;B. Zoheir;B. Lehmann;D. Frei;R. Burgess;C. E. Suh
喀麦隆东南部的巴图里金矿区是中非褶皱带（泛非）阿达马瓦-亚德域的一部分。它的下面是各种花岗岩，包括碱长石花岗岩、正二长花岗岩、花岗闪长岩和英闪长岩。地球化学数据表明，这些岩石是由大陆火山弧环境中 I 型英闪长质岩浆在氧化条件下分异形成的。对坎贝勒金伴生二长花岗岩-花岗闪长岩中的锆石进行 U-Pb 定年，得出的一致年龄为 619 ± 2 和 624 ± 2 Ma，而对碱长石花岗岩进行 Ar-Ar 定年，得出非高原最大年龄为 640-620 Ma。这些年龄表明巴图里花岗岩是在西非克拉通和刚果克拉通碰撞期间就位的。巴图里花岗岩的地球化学特征及其氧化状态（磁铁矿系列）是其他地方俯冲环境中与金相关的长英质岩石的典型特征。这些花岗岩与阿达马瓦-亚德域其他地区报告的花岗岩在年龄、成分和地球化学亲和力方面的相似性强化了早期的假设，即该域的花岗岩代表了区域规模岩基的一部分，在结构有利的地点通常具有小规模、高品位的含金石英脉。金矿化与巴图里花岗岩的时空关联可能表明存在区域规模、高吨位、与花岗岩相关的金矿石的潜力。
The Batouri gold mining area in southeastern Cameroon is part of the Adamawa–Yadé Domain of the Central African Fold Belt (Pan-African). It is underlain by a variety of granitic rocks, including alkali-feldspar granite, syeno-monzogranite, granodiorite, and tonalite. Geochemical data suggest that these rocks formed by differentiation of I-type tonalitic magma under oxidizing conditions in a continental volcanic arc setting. U–Pb dating of zircons from gold-associated monzogranite-granodiorite at Kambélé gave concordant ages of 619 ± 2 and 624 ± 2 Ma, while Ar–Ar dating of alkali-feldspar granite yielded a non-plateau maximum age of 640–620 Ma. These ages imply that the Batouri granitoids were emplaced during the collision of the West African Craton and the Congo Craton. The geochemical characteristics of the Batouri granitoids as well as their oxidized state (magnetite series) are typical of gold-associated felsic rocks in subduction settings elsewhere. The similarities in age, composition, and geochemical affinities of these granitoids with those reported from other localities in the Adamawa–Yadé Domain reinforce the earlier assumption that the granitic rocks of this domain represent parts of a regional-scale batholith, with commonly small-scale, high-grade auriferous quartz veins in structurally favourable sites. The spatial and temporal association of gold mineralization and the Batouri granitoids may suggest potential for regional-scale, high-tonnage, granite-related gold ore.