金属活动态测量在冲积平原覆盖区隐伏矿的试验研究——以安徽无为龙潭头硫铁矿为例

Application of selective leaching of mobile metals in overburden to mineral exploration in alluvial plain: A case study from Longtantou pyrite deposit ,Anhui province

随着出露区矿产资源的日益枯竭,覆盖区已逐渐成为矿产勘查的重点。传统化探方法难以在覆盖区发挥作用,而金属活动态测量法可以提取与深部隐伏矿体有关的矿化信息。该方法在冲积平原覆盖区还缺乏相关研究。以安徽无为龙潭头隐伏硫铁矿为例,开展土壤全量和金属活动态测量的试验研究。结果显示:土壤全量测量在隐伏矿体上方无异常显示。金属活动态测量中,Cu和S元素的水溶态,Fe元素的铁锰氧化物态和吸附态均呈现出高异常值,异常衬度达到2及以上。其中S元素的水溶态异常最明显,含量峰值达14.8×10^-9,背景值为4.81×10^-9,异常衬度3.08。其次,Cu元素的有机态和S元素的铁锰氧化物态呈现较高异常,异常衬度1.5以上。金属活动态测量提取的异常均位于隐伏矿体上方,且与赋矿主断裂空间关系密切。本次试验研究表明,金属活动态测量可以有效提取与龙潭头隐伏矿床有关的地球化学异常,该方法在冲积平原覆盖区应当有着较好的应用前景,但仍需要更进一步地研究,以建立相应的方法技术流程与标准。

With the depletion of mineral resources in outcropping areas,covered areas have gradually become the focus of mineral exploration. But traditional exploration of geochemical method can not be used in the covered areas. selective leaching of mobile metals in overburden (MOMEO) can extract geochemical information related to deep concealed orebodies. However,there is a lack of application of this method in alluvial plain terrain. Taking the Longtantou concealed pyrite in Anhui province as an example,soil geochemical survey was carried out by comparing the results from total digestion and the MOMEO. The results showed that there are no geochemical abnormal of elements in the total digestion. On the contrary,selective leach delivered satisfactory result. The water soluble state of Cu and S,the ferromanganese oxidized Fe showed high anomalies,and the abnormal contrast was over 2. The water soluble state of S is the most obvious one. The peak value is 14.8×10^-9,the background value is 4.81×10^-9,and the abnormal contrast is 3.08. The organic state of Cu and S,the ferromanganese oxidized of S showed high abnormality,and the anomaly contrast was about 1.5.The anomalies occur right above the ore body and/or the concealed fault which cut off the ore bodies. The above results show that the MOMEO can obtain geochemical anomalies over the hidden pyrite deposit of Longtantou. This method should have a good application prospect in alluvial plain terrain,but further research is still needed to establish the technical procedures and standards.