Diligencia Formation
The Diligencia Formation (Td) is a geologic formation cropping out in the Orocopia Mountains in southern California. It preserves mammal fossils dating to the Late Oligocene to Early Miocene (Arikareean in the NALMA classification).[1]
| Diligencia Formation Stratigraphic range: Late Oligocene-Early Miocene (Arikareean) ~25–20.4 Ma | |
|---|---|
| Type | Formation |
| Overlies | Proterozoic augen gneiss (basement) Maniobra Formation (in the north) |
| Thickness | 1,500 m (4,900 ft) |
| Lithology | |
| Primary | Conglomerate, sandstone, siltstone, limestone |
| Other | Interbedded basalt and andesite |
| Location | |
| Coordinates | 33.5°N 115.7°W |
| Approximate paleocoordinates | 32.2°N 107.5°W |
| Region | California |
| Country |  United States |
| Extent | Orocopia Mountains |
| Type section | |
| Named by | Crowell |
| Year defined | 1975 |
  Diligencia Formation (the United States)  Diligencia Formation (California) | |
Description
The non-marine Diligencia Formation, defined by Crowell in 1975, is composed of alluvial, fluvial, and lacustrine conglomerates, sandstones, siltstones and limestones. It contains interbedded basalt and andesite flows, dated by whole-rock and plagioclase K-Ar methods as ca. 24–21 Ma), and andesitic sills and dikes.[2][3]
See also
References
- Diligencia Formation at Fossilworks.org
- Coffey et al., 2019, p.481
- Canyon Spring at Fossilworks.org
- Woodburne & Whistler, 1973
Bibliography
- Coffey, Kevin T.; Raymond V. Ingersoll, and Axel K. Schmitt. 2019. Stratigraphy, provenance, and tectonic significance of the Punchbowl block, San Gabriel Mountains, California, USA. Geosphere 15. 479–501.
- Woodburne, M. O., and D. P. Whistler. 1973. An Early Miocene Oreodont (Merychyinae, Mammalia) from the Orocopia Mountains, Southern California. Journal of Paleontology 47. 908–912.
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