高密度电阻率法在菲律宾迪纳加特岛红土镍矿勘查中的应用

Application of High Density Resistivity Method on Lateritic Nickel Prospecting in Dinagat Island,the Philippines

菲律宾已成为我国主要的镍进口国,国内多个地勘队伍在该国开展了相关地质勘查工作,包括地质填图、土壤化探测量、钻探等。菲律宾迪纳加特岛红土层和超基性岩电性差异较大,因此选择高密度电阻率法对该区的红土层和超基性岩提接触面进行区分。根据钻孔试验测线推测钻孔处基岩埋深11m与实际钻孔揭露基岩埋深10m基本吻合,说明高密度电法能有效区分超基性岩及红土层界面。该区共布设了22条测线,经后期少量钻孔及浅井验证,发现高密度电阻率解释的基岩面均比钻探数据深,埋藏越浅,其相对误差较大,其与极距较大,浅部分辨率不足有关。

Since the Philippines is already a major nickel exporting country to China,thus many geological exploration units of our country have carried out related works including geological mapping,soil geochemical prospecting and drilling etc. The electrical property contrast of laterite and ultrabasic rock in the Dinagat Island is large,thus the high density resistivity method has been selected to define contact surface between laterite and ultrabasic rock in the island. According to cross borehole section line supposed bedrock depth 11 m and actual drilling revealed bedrock depth 10 m is basically agreed well,thus explained the method can effectively differentiate ultrabasic rock and laterite interface. 22 prospecting lines have been laid out in the area,after a few boreholes and test pits verification have found that the bedrock surface interpreted from high density resistivity is higher than drilling data,the shallower the buried depth,the larger the relative error,that is from the lager pole distance caused shallow part resolution deficiency.