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) ~ | |
| 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°30′N 115°42′W / 33.5°N 115.7°W |
| Approximate paleocoordinates | 32°12′N 107°30′W / 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
editThe 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]
Fossil content
editThe formation has provided the following fossils:[1]
- Mammals
See also
editReferences
edit- ^ a b Diligencia Formation at Fossilworks.org
- ^ Coffey et al., 2019, p.481
- ^ Canyon Spring at Fossilworks.org
- ^ Woodburne & Whistler, 1973
Bibliography
edit- Coffey, Kevin T.; Ingersoll, Raymond V.; Schmitt, Axel K. (2019), "Stratigraphy, provenance, and tectonic significance of the Punchbowl block, San Gabriel Mountains, California, USA", Geosphere, 15 (2): 479–501, Bibcode:2019Geosp..15..479C, doi:10.1130/GES02025.1
- Woodburne, M. O.; Whistler, D. P. (1973), "An Early Miocene Oreodont (Merychyinae, Mammalia) from the Orocopia Mountains, Southern California", Journal of Paleontology, 47: 908–912