Solid-Sample Geochemistry Study of Western Dixie Valley, Churchill County, Nevada -- Part II, Soil Geochemistry

Abstract

Numerous thermal springs present in northern Dixie Valley, Nevada, are the surface expression of a deep seated geothermal system. The structural setting, a complex asymmetric graben controls the location of surface springs and migration of thermal fluids to the surface. The distribution of arsenic and mercury in the soils of the valley correlates well with the occurrence of structures which may be in communication with the underlying geothermal system. Generally anomalous arsenic values occur along structures near the playa where fine grained sediments and a high water table occur. Mercury values are uniformly low near this playa but are typically anomalous along structures in the coarser fan deposits. The complementary geochemical signatures of arsenic and mercury which arise from basic differences in elemental chemical behavior have been useful in delineating the structural trends of the valley. The structural model indicated by the geochemistry and results of drilling suggest future targets should be selected east of the Dixie Meadows fault, within the "inner graben".