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
TypeFormation
OverliesProterozoic augen gneiss (basement)
Maniobra Formation (in the north)
Thickness1,500 m (4,900 ft)
Lithology
PrimaryConglomerate, sandstone, siltstone, limestone
OtherInterbedded basalt and andesite
Location
Coordinates33°30′N 115°42′W / 33.5°N 115.7°W / 33.5; -115.7
Approximate paleocoordinates32°12′N 107°30′W / 32.2°N 107.5°W / 32.2; -107.5
RegionCalifornia
Country United States
ExtentOrocopia Mountains
Type section
Named byCrowell
Year defined1975
Diligencia Formation is located in the United States
Diligencia Formation
Diligencia Formation (the United States)
Diligencia Formation is located in California
Diligencia Formation
Diligencia Formation (California)

Description

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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]

Fossil content

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The formation has provided the following fossils:[1]

Mammals

See also

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References

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  1. ^ a b Diligencia Formation at Fossilworks.org
  2. ^ Coffey et al., 2019, p.481
  3. ^ Canyon Spring at Fossilworks.org
  4. ^ Woodburne & Whistler, 1973

Bibliography

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  • 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