上黑龙江植被覆盖区水系沉积物金异常评价

Evaluation on gold anomaly of stream sediment in plant-covered area of the upper part of Heilongjiang

研究区位于上黑龙江断陷和额尔古纳隆起两个次级构造单元。受断裂构造和岩浆活动的影响 ,Au在岩浆岩、变质岩、沉积岩、火山岩区分布及分配不均匀 ,变化趋势为沉积岩 >变质岩>火山岩 >岩浆岩。Au在水系沉积物中以化学作用形式搬运迁移 ,一般距离为 80 0～ 16 0 0m。金异常产出明显受断裂控制 ,并与燕山期岩浆活动密切相关。异常下限为 3 0× 10 - 9,是Au低背景值区。根据金异常地化特征、地质环境 ,采取水系加密法和土壤剖面法 ,结合路线地质调查 。

The study area is located in both the upper Heilongjiang faulted depression and Erguna uplife. With influence of faulted structure and magma activity, Au distribution shows uneven in magmatic rocks, metamorphic rocks, sedimentary rocks and volcanic rocks. The change trend is sedimentary rocks>metamorphic rocks>volcanic rocks>magmatic rocks. Au migrates in stream sediment in form of chemical attack, the removing distance is usually 800～1 600 m. Gold anomaly occurrence is obviously controlled by the fault, and related to the magma activity in Yansan age. The minimum value of the anomaly is 3 0×10 -9 , belonging to the low background value area of Au. Based on the geological characters and settings of gold anomaly, using drainage infilling method and soil profile method, combining with the route geological survey, the existence of gold anomaly has been verified and the source of the anomaly is found.