Gravity and Ground Magnetic Data from Selected Traverses in the Amargosa Desert and Vicinity, Nevada and California

Index map showing location of Amargosa Desert basin study area (outlined) and distribution of main geologic units of the surrounding region (from figure 1)

High-resolution aeromagnetic surveys of the Amargosa Desert region have revealed many magnetic anomalies of varying character. High-amplitude anomalies in the northern part of the region are produced by the volcanic rocks of the southern Nevada volcanic field (SNVF). Contrasted with these are low-amplitude anomalies over a broad area in the southern and southwestern part of the aeromagnetic survey that reflect pre-Cenozoic, largely nonmagnetic basement rocks exposed in the different ranges. More subtle, isolated anomalies are distributed throughout the region and indicate sources that are overlain by, or included within, the alluvial deposits. We have investigated some of the latter low-amplitude anomalies using gravity and magnetic techniques in an attempt to help characterize their causative bodies. Our depth-to-magnetic-source calculations indicate that the anomalies investigated have sources within the alluvial fill and agree well with results from similar studies in the region. Possible source rocks include Miocene tuff of the SNVF and/or Tertiary rocks of the Death Valley volcanic field.