大兴安岭漠河砂金富集区岩金找矿思路

大兴安岭漠河地区砂金极为丰富,充分研究区内的地质构造特征、砂金分布和富集规律、区域剥蚀深度等,利用砂金信息寻找岩金是区内岩金找矿工作的有效手段之一.利用砂金矿只能寻找剥蚀残留的那一部分岩金矿.对物源区剥蚀程度和探矿构造分析研究,是在砂金富集区内圈定岩金找矿靶区的关键.溶蚀系数可指示砂金是近或远原生源金矿.Pb同位素可指示成矿母岩,利用矿石、岩浆岩、地层和基底铅同位素全方位对比来判别铅同位素的来源是一种近年来国际上认同的办法,砂矿评价中利用铅同位素寻找母岩已获得成功.本区砂金Pb同位素特征值与源区极为相似,可做为砂金富集区寻找岩金的指示元素.本文旨在论述砂金富集区内砂金与岩金空间位置关系、成因上的联系及岩金成矿特点,为下一步岩金找矿工作提供思路和方法.

PROSPECTING FOR GOLD DEPOSIT IN PLACER GOLD ENRICHED AREAS IN MOHE, DAXINGANLING REGION

Placer gold is rich in Mohe, Daxinganling region, Heilongjiang Pr ov ince. It is an effective approach to search gold deposit using the information o f gold placer, with the study on tectonic features, distribution and concentrati on of gold placer and regional denudation depth. Analysis on the tectonics and d egree of denudation is the key step to locate the targets in placer gold enriche d areas. The coefficient of dissolution can indicate the source of placer gold. Isotopes of Pb can reveal the parent rock for mineralization. The correlation st udy of ore,magmatic rocks, strata and Pb isotopes of basement has become an inte rnationally recognized way to distinguish the origin of Pb isotopes. Using Pb is otopes to trace parent rocks has been successful in the assessment of ores. The characteristic values of Pb isotopes of the region resemble those of the source region.Thus the element can be employed as an indicator for gold deposit prospec ting in placer gold enriched area.