阿拉善恩格尔乌苏蛇绿岩带成矿地质特征与成矿预测

Metallogenic geological characteristics and metallogenic prediction of Alashan Engel Wusu ophiolite belt

本文通过1∶5万地质调查工作,详细查明了恩格尔乌苏蛇绿岩带成矿地质背景及物、化探异常特征;蛇绿岩带内圈定了7个多金属矿点和3条Sb异常带;后者元素峰值高,浓集中心明显,多元素异常套合好,且对应有明显的航磁异常。蛇绿岩带内多金属矿化主要与其内部的石炭纪中酸性侵入岩及部分高背景值岩块有关,成矿时间应为早石炭世,俯冲构造持续活动形成叠加于NE向蛇绿岩带之上的NWW向构造,前者主要为区域控岩和导矿构造,后者则为区内主要控矿构造。综合分析认为,蛇绿岩带形成过程限定了区域成矿时间,带内地质体性质和空间分布决定了不同矿种和矿床类型,物化探工作可以有效圈定找矿靶区,结合不同找矿标志可开展矿产勘查工作。对恩格尔乌苏蛇绿岩带成矿规律的总结,对区域周边及同类地区成矿预测及矿产勘查工作部署具有指导意义。

Through 1∶50000 geological survey,the metallogenic geological background,geophysical and geochemical anomaly characteristics of Engel Wusu ophiolite belt have been found out.Seven polymetallic ore occurance and three Sb anomaly zones are delineated within the ophiolite zone.The latter has high element peak value,the concentration center is obvious,the multi-element abnormality is well integrated,and the aeromagnetic abnormality is also clear.The polymetallic mineralization in the ophiolite belt is mainly related to the Carbonifer‐ous middle acid intrusive rocks and some high background rocks.The mineralization time should be the early Carboniferous.The continuous activities of subduction structure formed the NWW-trending structure superimposed on the NE-trending ophiolite belt.The former is mainly the regional rock-controlling and ore-guiding structure,while the latter is the main ore-controlling structure in the area.Comprehensive analysis shows that the formation process of ophiolite belt limits the time of regional mineralization.The properties and spatial distribution of plast in the belt determine different ore species and deposit types.Physical and chemical exploration can effectively delineate the prospecting target area.Mineral exploration can be carried out according to different prospecting indicators.The summary of metallogenic regularity of the Engel Wusu ophiolite belt is of guiding significance to metallogenic prediction and mineral exploration deployment in the surrounding and similar areas.