甘肃南部石鸡坝地区金地球化学特征及找矿意义

石鸡坝地区的金地球化学特征受地层、构造和沿构造发育的岩脉的控制,其水系沉积物和土壤测量的异常主元素组合为Au、Hg、As、Sb。根据不同小区的地质特征和背景,选用不同的异常下限圈定异常,尤其是Au异常,不但异常规模大,峰值高,而且具很好的浓度分带,浓集中心明显。多处异常浓集部位采用工程揭露验证,发现规模和品位较可观的金矿体,已经形成了阳山(大型)、新关(中型)、后斗湾(小型)、关牛湾(小型)等金矿床。矿体与异常的对应性相当吻合,说明水系沉积物和土壤测量方法在该区的效果和结果可靠。通过对比和分析,提出了对区内其他异常和弱小异常研究和验证的必要性,找到该类金矿的前景很大。

GOLD GEOCHEMICAL CHARACTERISTICS OF SHIJIBA AREA IN SOUTHERN GANSU AND THEIR ORE-PROSPECTING SIGNIFICANCE

Gold geochemical characteristics of Shijiba area are controlled by strata, structures and dykes developed along structures, and the major element association of stream sediment and soil anomalies is composed of Au, Hg, As and Sb. According to geological characteristics and backgrounds of different units, different anomaly thresholds were selected to delineate anomalies.Gold anomalies are characterized by large sizes, high peak values, good concentration zoning and obvious concentration centers. Engineering exposure and inspection of quite a few anomaly concentration positions led to the discovery of gold ore bodies with considerable sizes and grades, which formed Yanshan (large-sized), Xinguan (medium-sized), Houdouwan (small-sized) and Guanniuwan (small-sized) gold deposits. Ore bodies are quite consistent with anomalies, suggesting that stream sediment survey and soil survey are reliable and effective methods in this area. Based on contrast and analysis, the author holds that it is necessary to study and verify other anomalies and "weak anomalies", which may lead to the discovery of other gold deposits in this area.