壤中汞气测量在广东凡口厚层疏松物覆盖地区的应用

在地表疏松物厚20—40m的地区,壤中汞气测量显示了埋深200余m的盲矿体,它对疏松层下断裂带的分布也有清晰地指示。汞在地表疏松层中含量为0.06—0.2PPm,主要以气态、土壤胶体及粘土矿物吸附态形式存在。汞在铅锌矿石中含量为14—320ppm,以类质同象形式分散分布于单矿物中。壤中汞气异常是矿床在氧化过程中,痕量汞从矿石中解脱出来,以气态沿各种裂隙进入地表疏松层。

THE APPLICATION OF MERCURY VAPOUR SURVEY IN SOIL AIR OF THE THICK OVERBURDEN AREA OF FANKOU, GUANGDONG PROVINCE

It is demonstrated in this paper that blind ore buried as deep as 200m below the surface and fault zones covered by thick overdurben can be indicated by mercury vapour anomalies in soil air. Hg vapour concentration in the near surface air is determined to be 8 ng/m3,whereas the background concentration of Hg vapour in soil air is 50ng/m3. The contrast between background and anomaly, being as high as 200, provides a reliable recognition of anomalies.According to eletron probe analysis, the primary Hg occurs isomorphically in sphalerite. The formation of Hg vapour is attributed to the oxidation of sulphide minerals. Several unknown anomalies have been discovered during the investigation, which were justified to be drilled on the basis of the similarity to that of known ore bodies in shape and concentration.