化探数据挖掘在金矿找矿及靶区优选中的应用——以甘肃玉石山地区为例

由于自然界中Au元素呈微粒状、不均匀状态分布,致使部分金矿床(点)没有与之对应的Au元素异常出现,增加了通过元素异常开展地质找矿和成矿预测研究的难度。本文依据地学大数据"查明数据间的相关关系,解决地质问题"这一基本思路,以甘肃玉石山地区化探数据为研究对象,建立起研究区全样本Au元素回归模拟模型和异常样本Au元素回归模拟模型,分别计算全样本Au元素回归理论值(Au Q)和异常样本的回归理论值(Au Y)。通过异常查证,在Au Q异常区发现金矿点1处,在Au Y异常区发现金矿点3处(一处达到小型规模),取得了很好的找矿效果。进一步对Au、Au Q、Au Y分别做正规化处理相加获得综合理论值(Au H),以Au H圈定的综合异常使研究区75%金矿床(点)分布在研究区7. 1%面积范围内,有效地缩小了找矿靶区的范围,解决了小范围研究区内因已知矿床(点)不足而无法开展定量找矿预测的难题。结合异常强度和地质背景分析,在研究区划分出3级共10个找矿靶区,为今后在该区找矿工作提供了基础依据。

Application of geochemical data in gold prospecting and target selecting: Taking the Yushishan area in Gansu Province as a case

Due to the uneven distribution of Au in the natural world, some gold deposits (or spots) do not have corresponding abnormalities in the ground surface, which makes it more difficult to carry out geological prospecting and metallogenic prediction through elemental anomaly investigation. Based on the basic principle of geosciences big data "identifying the correlation between data and solving geological problems", this paper takes the chemical prospecting data of the Yushishan area in Gansu Province as an example to establish a full-sample Au element regression simulation model and abnormal sample Au element regression simulation. By using this model, the full-sample Au regression theoretical value (AuQ) and the abnormal sample theoretical value (AuY) are calculated. Through anomaly inspection, one gold occurence was found in the AuQ anomaly zone, and three gold deposits (one reaches small scale) were found in the AuY anomaly zone, showing a good prospecting effect. The comprehensive theoretical values (AuH) were obtained by adding normalization to Au, AuQ and AuY, respectively. By AuH delineated comprehensive anomaly analysis, 75% of the gold deposits (spots) in the study area were found distributed within an area of 7.1% of the study area. The scope of the ore-finding target area has been narrowed down, and thus the difficulty in conducting quantitative ore-finding predictions in a small-scale research area due to a shortage of known deposits (spots) has been solved. Combined with analysis of the anomalous intensity and geological backgrounds, a total of 10 prospecting target areas in 3 levels were divided into the prospecting target area, which provided the basis for future prospecting work in this area.