Geophysical observations in parts of the Grants District, McKinley County, New Mexico

Abstract

Geophysical observations near Haystack Mesa in the Grants district, McKinley County, New Mexico, had the dual objective of investigating the unusual occurrence of negative aeromagnetic anomalies in close association with airborne radioactivity anomalies, and of investigating other geophysical methods which might assist directly or indirectly in the search for uranium ores in the Grants district. Ground magnetometer tests indicate the apparent correlation shown in the airborne data is fortuitous. Ground magnetometer and self-potential surveys on an experimental basis may be justified to test the applicability of these methods in future exploration. Aeroagnetic surveys would aid field geologic studies in locating concealed Tertiary intrusives, which may have affected ore localization. Continuation of the airborne radiometric survey of the Todilto limestone outcrop is recommended to search for promising areas that might contain additional deposits.