Interpretation of an aerial radiometric survey of the San Gorgonio Wilderness Area and vicinity, San Bernardino County, California

The aerial radiometric data for the San Gorgonio Wilderness Area show slight correlation with mapped geology and contain no information of economic significance. Precambrian and modified Precambrian crystalline rocks have more eTh compared to Mesozoic plutonic rocks and one rock unit mapped as a pluton has slightly more K. These rocks have essentially uniform ratios of eU/eTh and eU/K despite their different origins. The ratios and also show that part of the granodiorite of Manzanita Springs could be somewhat deficient in eTh and K. It is concluded that the mapped radioelement distributions are within reasonable limits for the rock types involved, and there is no immediate evidence on any anomalous concentrations of radioactive minerals within the Wilderness Area.