摘要:
印尼苏门答腊岛西部的苏利特河铜矿床代表了侏罗纪-早白垩世岩浆弧相关的铜金成矿期次。为了总结其特征并指导该区找矿实践,本文对其地质背景、岩相学和主量及微量元素特征进行了研究。岩石地球化学特征表明:该矿床矽卡岩主量元素与岩浆岩相比,其 CaO 含量增多,SiO2、Al2O3、K2O 以及 Na2O 含量降低;在 FAM 图解和 FeOt-MgO-Al2O3图解中,矿化矽卡岩落在变质闪长斑岩附近,但是二者的 REE 配分模式不尽相同:闪长斑岩岩体具有更高的Σw(REE)含量和 Eu 正异常,而矽卡岩普遍表现为 Eu 负异常。综合主量元素地球化学和年代学的证据,苏利特河矿床时代可能为早侏罗世以后,属于造山后和碰撞后阶段的板内岩浆活动的产物。
Abstract:
Sulit Air copper deposit belongs to the Jurassic- early Cretaceous magma arc related copper-gold metallogenic period of Sumatra, Indonesia. In order to summarize the characteristics of this deposit and to guide the prospecting in this area, this article study the geology, petrology and geochemistry of Sulit Air. Geochemistry characteristic shows that the skarn rocks have more CaO and less Al2O3, K2O, Na2O content than the igneous rock;In the FAM diagram and FeOt-MgO-Al2O3 diagram, the skarn rock dropped near the igneous rocks area. Howev-er, the REE pattern of those two rocks are different, the Σw (REE) of igneous rock is higher than skarn rock; the skarn rocks have negative europium anomalies rather than positive anomalies in the igneous rock. In conclusion, the age of Sulit Air deposit is later than early-Jurassic and its ore-forming setting belongs to the post-orogenic and post-collisional volcanism.
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