Geophysical investigation of Mono Basin, California

Bulletin of the Geological Society of America
By: , and 



Gravity and seismic studies in Mono BasinMono County, California, completed during the summer of 1957 revealed a large, roughly triangular block that had subsided about 18,000 ± 5000 feet and received an accumulation of about 300 ± 100 cubic miles of light clastic sediments and volcanic material of Cenozoic age. The seemingly near-vertical faults that bound this great block are displaced toward the center of the basin from the surrounding mountain masses, but in general they are parallel to well-defined Basin and Range trends. The gravity minimum anomaly associated with the Mono Basin structure has a residual gravity relief of about 50 mgals, and the lowest gravity readings (on Paoha Island) yield a complete Bouguer gravity value of about - 260 mgals with respect to the International Ellipsoid. The computed depth of subsidence is based on a density of 2.3 gms/ cm3 for the basin fill and 2.7 gms/cm3 for the basement rocks. Seismic-refraction profiles at several places in the basin demonstrate that the Cenozoic deposits are thick where the gravity is low and relatively thin where the gravity is higher. Along common seismic and gravity profiles steep seismic dips coincide with steep gravity gradients. Numerous seismic reflections are present within the basin fill. Anomalies on four aeromagnetic profiles are related in part to volcanic material within the Cenozoic section. It is concluded that Mono Basin may be a volcano-tectonic depression caused by subsidence along faults, following extrusion of magma from a magma chamber at depth. Volcanic rocks of Pliocene(?) and Pleistocene ages are exceptionally abundant in this area.

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Publication type Article
Publication Subtype Journal Article
Title Geophysical investigation of Mono Basin, California
Series title Bulletin of the Geological Society of America
DOI 10.1130/0016-7606(1960)71[415:GIOMBC]2.0.CO;2
Volume 71
Issue 4
Year Published 1960
Language English
Publisher Geological Society of America
Description 34 p.
First page 415
Last page 448
Country United States
State California
Other Geospatial Mono Lake
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