Kl. Mickus et M. Mccurry, Gravity and aeromagnetic constraints on the structure of the Woods Mountains volcanic center, southeastern California, B VOLCANOL, 60(7), 1999, pp. 523-533
The Woods Mountain volcanic center is a well-exposed, mildly alkaline volca
nic center that formed during the Miocene in southeastern California. Detai
led geologic mapping and geochemical studies have distinguished three major
volcanic phases: precaldera, caldera forming, and postcaldera. Geologic ma
pping indicates that caldera formation occurred incrementally during erupti
ons of three large ignimbrites and continued into a period of voluminous in
tracaldera lava-flow eruptions. Rhyolitic ignimbrites and lava flows within
the caldera are associated with large amplitude, circular gravity, and mag
netic minima that are among the most prominent gravity and magnetic anomali
es in southeastern California. Analysis of a Bouguer gravity anomaly map, r
educed-to-the-pole magnetic intensity map, and three-dimensional gravity an
d magnetic models indicates that there is a single, funnel- to bowl-shaped
caldera approximately 4 km thick and approximately 10 km wide at the surfac
e. This model is consistent with other siliceous, pyroclastic-filled calder
as on continental crust, except that most siliceous volcanic centers associ
ated with more than one eruption are characterized by more than one caldera
.