Soil Radon and Elemental Mercury Distribution and Relation to Magmatic Resurgence at Long Valley Caldera
STANLEY N. WILLIAMS 1
1 Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire 03755
The response of a large geothermal system to magmatic resurgence was analyzed by a survey of soil gas radon and elemental mercury at 600 sites in the silicic Long Valley Caldera, California. The broad geochemical anomaly over the caldera has superimposed on it a small zone of pronounced radon enrichment and mercury depletion coincident with the surface projection of a postulated dike of rising magma. Soil gas geochemistry studies can complement traditional geophysical and geodetical methods in the evaluation of potential volcanic eruption hazards.
Submitted on February 5, 1985
Accepted on May 30, 1985