Jurassic ash-flow sheets, calderas, and related intrusions of the Cordilleran volcanic arc in southeastern Arizona: Implications for regional tectonics and ore deposits
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Abstract
Volcanologic, petrologic, and paleomagnetic studies of widespread Jurassic ash-flow sheets in the Huachuca-southern Dragoon Mountains area have led to identification of four large source calderas and associated comagmatic intracaldera intrusions. Stratigraphic, facies, and contact features of the caldera-related tuffs also provide constraints on the locations, lateral displacements, and very existence for some major northwest-trending faults and inferred regional thrusts in south-eastern Arizona. For example, the intricate Cochise thrust system, as mapped by others in the southern Dragoon Mountains, consists instead of primary depositional contacts within caldera-fill megabreccia, and the inferred regional thrusts do not exist, at least as previously interpreted. Silicic alkalic compositions of the Jurassic caldera-related, ash-flow tuffs; bimodal associated mafic magmatism; and interstratified coarse sedimentary deposits provide evidence for synvolcanic extension and rifting within the Cordilleran magmatic arc. Gold-copper mineralization is associated with subvolcanic intrusions at several of the Jurassic calderas.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Jurassic ash-flow sheets, calderas, and related intrusions of the Cordilleran volcanic arc in southeastern Arizona: Implications for regional tectonics and ore deposits |
| Series title | Geological Society of America Bulletin |
| DOI | 10.1130/0016-7606(1992)104<0032:JAFSCA>2.3.CO;2 |
| Volume | 104 |
| Issue | 1 |
| Year Published | 1992 |
| Language | English |
| Publisher | Geological Society of America |
| Description | 8 p. |
| First page | 32 |
| Last page | 39 |
| Country | United States |
| State | Arizona |