Santiam Pass has been assessed for its geothermal energy potential, and there is a drill corehole extending to a depth of south of the highway area. In addition to the expected basaltic andesite lava and a number of dikes, the core also detected unusual basalt, andesite, and coarse sediment indicative of debris flows. The dating for these samples cannot be confirmed because of the close proximity of Brunhes-aged dikes, which likely heated nearby rock and caused the loss of radiogenic argon.