不整合関連型ウラン鉱床探査における物理探査の新たな試み

抄録

This paper introduces our recent trials on geophysical surveys used in exploration for uranium deposits in the Athabasca basin, northern Saskatchewan, Canada. The uranium deposits are associated with the unconformity between the Helikian (Middle Proterozoic) Athabasca sandstone and an older crystalline basement.
The current standard geophysical exploration flow in this area consists of a series of geophysical methods with electromagnetic methods as its core. That is, in view of the association between non-magnetic basement graphitic metasediments and the uranium deposits, air-borne magnetic and electromagnetic methods are the primary reconnaissance tools, and they are followed by ground electromagnetic methods to delineate the graphitic horizons prior to exploratory drilling.
Here, I show that three-component time domain electromagnetic measurements can provide a more accurate estimation of the locations of the conductor axes (intersections between the graphitic horizons and the unconformity) than conventional two-component measurements, and that direct current resistivity mapping is effective for picking shallow alteration zones.