Reconnaissance of radioactive rock of the Hudson Valley and Adirondack Mountains, New York

Abstract

In August 1949 a carborne reconnaissance for radioactivity was made along 3,750 miles of road in the Paleozoic rocks of the Hudson Valley and the pre-Cambrian rocks of the Adirondack Mountains in eastern and central New York state. In the Paleozoic rocks the average radioactivity of the most strongly radioactive rocks is 0.003 percent equivalent uranium. The area underlain by pre-Cambrian rocks in the northwestern and southeastern parts of the Adirondacks contain the greatest concentration of abnormally radioactive rocks and glacial materials. This radioactivity is most apparent near the contacts of the igneous and metamorphic rocks where the average range of equivalent uranium content is estimated to be 0.003-0.004 percent. Pegmatites contain as much as 0. 043 percent uranium and 0.62 percent thorium. Iron slag containing 0.030 percent equivalent uranium was found near Moriah Center, and uranium and thorium in iron minerals have contributed to the radioactivity at several other abnormally radioactive localities.