Barstow Formation

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Barstow Formation
Ma
Barstow Formation exposed in Owl Canyon near Barstow, California.
TypeSedimentary
Lithology
Primarylimestone, shale, siltstone, sandstone, tuff
Otherconglomerate
Location
RegionMojave Desert,
California
CountryUnited States
ExtentNorthern San Bernardino County, Southeastern California
Type section
Named forBarstow, California
Named byHershey (1902)

The Barstow Formation is a series of limestones, conglomerates, sandstones, siltstones and shales exposed in the Mojave Desert near Barstow in San Bernardino County, California.[1][2]

It is of the early to middle

NALMA
).

The sediments are

footprints.[4] The formation is also renowned for the fossiliferous concretions in its upper member, which contain three-dimensionally preserved arthropods
.

Fossils

Mammals

Mammals from various groups are found in the Barstow Formation. Herbivorous groups include horses, peccaries,

oreodonts, camels, proghorns and other horned artiodactyls, proboscideans, and a rhinoceros. The unit also produces a surprising number of carnivorous mammals, reminiscent of the modern east African savanna to which it has been compared climatically and ecologically. These include a number of borophagines, mustelids, nimravids, Amphicyon, and the primitive bear Hemicyon.[5]

Arthropods

The arthropods in the upper member of the Barstow Formation are preserved in concretions. The concretions are calcareous and range from 0.125 cm3 to 125 cm3. The fossils are typically three-dimensional and, on occasion, exhibit internal anatomy. Due to the preservation of soft-tissue, the Barstow Formation has been identified as a Konservat-Lagerstätte deposit. The fauna was first recognized in 1954 by Allen M. Basset and Allison "Pete" R. Palmer.[6]

The concretions from the Barstow Formation preserve both

Coleoptera (Schistomerus californese), and Anostraca (Archaebranchinecta barstowensis).[7][8][9]

See also

References

  1. ^ Dibblee, T.W., Jr. (1967). Areal Geology of the Western Mojave Desert, California. Geological Survey Professional Paper no. 522. United States Government Printing Office, Washington D.C.
  2. ^ Dibblee, T.W., Jr. (1968). Geology of the Fremont Peak and Opal Mountain Quadrangles, California. California Division of Mines and Geology, San Francisco.
  3. ^ a b Woodburne, M.O., Tedford, R.H., Swisher III, C.C. (1990). Lithostratigraphy, biostratigraphy, and geochronology of the Barstow Formation, Mojave Desert, southern California: Geological Society of America Bulletin, Vol. 102, p. 459-477.
  4. ^ Lindsay, E.H. (1972). Small Mammal Fossils from the Barstow Formation, California. University of California Publications in Geological Sciences, Vol. 93. University of California Press, Berkeley.
  5. ^ Pagnac, Darrin C.; Reynolds, Robert E. (2006). "The fossil mammals of the Barstow Formation" (PDF). Making Tracks Across the Southwest: 65–70.
  6. ^ Palmer, A.R., Basset, A.M. (1954). Nonmarine Miocene arthropods from California. Science, Vol. 102, p.228-229
  7. S2CID 129795195
    .
  8. S2CID 86407946
    .
  9. doi:10.1651/10-3449.1
    .
  • Syncline in the Barstow Formation exposed in Rainbow Basin near Barstow, California.
    Syncline in the Barstow Formation exposed in Rainbow Basin near Barstow, California.
  • Syncline in the Barstow Formation, lower parking lot of Calico Ghost Town near Barstow, California.
    Syncline in the Barstow Formation, lower parking lot of
    Calico Ghost Town
    near Barstow, California.
  • Anticline in the Barstow Formation (Miocene) at Calico Ghost Town near Barstow, California.
    Anticline in the Barstow Formation (Miocene) at Calico Ghost Town near Barstow, California.
  • Cameloid footprint (Lamaichnum alfi Sarjeant and Reynolds, 1999; convex hyporelief) from the Barstow Formation of Rainbow Basin, California.
    Cameloid footprint (Lamaichnum alfi Sarjeant and Reynolds, 1999; convex hyporelief) from the Barstow Formation of Rainbow Basin, California.


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