Assemblages of Paleozoic age and less significant Triassic and possibly Cretaceous-Tertiary volcanic rocks constitute the Sierra El Aliso, 186 km east-southeast of Hermosillo, Sonora. The Paleozoic section consists of approximately 2000 m of allochthonous Ordovician to Permian pelagic and hemipelagic deposits that accumulated in continental slope, continental rise and ocean floor (?) environments. The lower Paleozoic is characterized by graptolitic black shale and radiolarian chert, quartzite, argillite and local limestone. The upper Paleozoic is predominantly turbidite carbonates rich in benthonic foraminifera, and conodont faunas, subordinate bedded chert, siltstone, sandstone and chert-clast conglomerate. After Early Permian time, but prior to the deposition of the Late Triassic Barranca Group the Paleozoic section was imbricated along south-southeast vergent thrust faults. The Triassic rocks unconformably overlie the Paleo-zoic strata and all thrust faults. The Triassic and older rocks are overlain by the Cretaceous-Tertiary volcanics.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/244082 |
| Date | January 1988 |
| Creators | Bartolini, Claudio |
| Contributors | Stewart, John, Coney, Peter J., Ruiz, Joaquin, Bartolini, Claudio |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Thesis-Reproduction (electronic) |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the Antevs Library, Department of Geosciences, and the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author or the department. |
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