大兴安岭北段上马场金矿床成矿特征及找矿标志

上马场金矿床位于兴安地块东缘,大兴安岭北段金、铜、铅、锌多金属成矿区内。矿体主要产于龙江组中性火山岩中,次为光华组中酸性火山岩。结合区域地质背景及矿床地质特征,初步认为金矿成矿作用与白垩系火山活动关系密切;NE向火山断裂为主要容矿构造;硅化、碳酸盐化与金矿化关系密切。地球物理特征显示低缓正负相间磁场、低电阻率地区为找矿有利地段,地球化学特征显示Au、Ag、As、Sb等成矿元素相关关系密切,组合异常为找矿的重要标志特征。

Metallogenic characteristics and prospecting signs of Shangmachang Gold Deposit in the north part of Great Khingan Mountains

Shangmachang Gold Deposit is located within the gold,copper and zinc polymetallic metallogenic zone in the north part of Great Khingan Mountains on the east margin of Khingan massif. The ore body mainly originates in the intermediate volcanic rocks which belong to Longjiang formation and secondly in the acidic volcanic rocks which belong to Guanghua formation. Taking the regional geological background and the geological characteristics into consid-eration,the paper thinks that the mineralization is closely related to the Cretaceous volcanic activities. The main ore-depositing structure is NE-trending volcanic fracture. The silicification and carbonation are closely related to gold min-eralization. The geophysical characteristics indicate that the region with low and slow positive -negative alternating magnetic field and low electrical resistivity is favorable for prospecting. The geochemical characteristics indicate that the mineralized elements,such as Au,Ag,As and Sb have close accompanying relations with each other,and the geo-chemical assemblage anomaly is the important characteristic of prospecting sings.