Earth:Diligencia Formation

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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
Coordinates [ ⚑ ] : 33°30′N 115°42′W / 33.5°N 115.7°W / 33.5; -115.7
Paleocoordinates [ ⚑ ] 32°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
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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]

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]

Fossil content

The formation has provided the following fossils:[1]

Mammals

See also


References

  1. 1.0 1.1 Diligencia Formation at Fossilworks.org
  2. Coffey et al., 2019, p.481
  3. Canyon Spring at Fossilworks.org
  4. Woodburne & Whistler, 1973

Bibliography