The age of the Keystone thrust: laser-fusion 40Ar/39Ar dating of foreland basin deposits, southern Spring Mountains, Nevada
Nonmarine sedimentary and volcaniclastic foreland-basin deposits in the Spring Mountains are cut by the Contact and Keystone thrusts. These synorogenic deposits, informally designated the Lavinia Wash sequence by Carr (1980), previously were assigned a Late Jurassic to Early Cretaceous(?) age. New 40Ar.39Ar laser-fusion and incremental-heating studies of a tuff bed in the Lavinia Wash sequence support a best estimate age of 99.0 ?? 0.4 Ma, indicating that the Lavinia Wash sequence is actually late Early Cretaceous in age and establishing a maximum age for final emplacement of the Contact and Keystone thrust plates consistent with the remainder of the Mesozoic foreland thrust belt. -from Authors
Citation Information
Publication Year | 1990 |
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Title | The age of the Keystone thrust: laser-fusion 40Ar/39Ar dating of foreland basin deposits, southern Spring Mountains, Nevada |
Authors | R. J. Fleck, M. D. Carr |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Tectonics |
Index ID | 70015736 |
Record Source | USGS Publications Warehouse |