Utilizing soil geochemistry, ground magnetic, and radiometric surveys to outline a blue ridge, ultramafic body in North Carolina

Abstract

Abstract A soil geochemical survey for Ni plus magnetic and radiometric surveys were used to outline a small dunite body on Rich Mountain, North Carolina. The dunite body is poorly exposed and is enclosed by garnet-bearing amphibolite of the Ashe Formation. Of the geophysical techniques used, the magnetic survey gives a better definition of the known extent of the body than the radiometric survey. However, the 400-ppm Ni contour from the soil program appears to best define the dunite and suggests that it extends farther to the north and east than was indicated from geologic mapping. Though HF digestion yields higher Ni values than HNO 3 + HCl digestion, the patterns are the same. The Mn content of the soil at the Rich Mountain locality probably could also be used to outline the dunite body.