1. Aerial gamma-ray color contour maps of regional surface concentrations of potassium, uranium, thorium and composite-color maps of uranium, potassium, thorium, and their ratios in New Mexico Yale Public content 1989. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; For sale by Map Distribution. English. Public. New Mexico.