Geophysical expression of the northern part of the Mono-Inyo volcanic chain, Mono Basin, California.

摘要

The Mono Domes are located at the northernmost end of the Mono-Inyo volcanic chain just north of the Long Valley Caldera and include more than 30 overlapping domes and coulees that follow an arcuate trend. A shallow basement high, possibly bounded by a fault, as suggested by potential-field models of data collected in Mono Basin, California, may have influenced the geometry and location of the Mono Domes.;Over 320 new gravity stations and approximately 297 line-km of ground magnetic data were collected during the summer of 2010 to investigate the subsurface structure of the Mono Basin. Regional gravity data were collected throughout the basin, and ground magnetic data were collected on major roads along numerous transects throughout the region, one of which was coincident with a seismic refraction line. Gravity and magnetic data were compiled with pre-existing data from studies dating back to the 1960's to produce a new regional isostatic gravity anomaly map and ground magnetic profiles throughout the basin.;Aeromagnetic and ground magnetic data revealed an anomalous ring-shaped magnetic high centered over Aeolian Buttes, whose eastern margin follows the arcuate trend of the Mono Domes. This magnetic high is essentially coincident with what Kistler (1966) inferred to be a ring-fracture. Two-dimensional forward modeling of potential field data along a profile across the basin suggests a basement high, or ridge, at roughly 700 m depth, the eastern edge of which lies beneath the Mono Domes. The basement ridge is probably fractured, as suggested by potential field data, indicating a possible pre-existing fault beneath the Mono Domes. This fault is along the eastern edge of the basement ridge and could have served as a conduit for the Mono Domes feeder dike.