Camp Rice Formation

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Camp Rice Formation
Stratigraphic range:
TypeFormation
Unit ofSanta Fe Group
OverliesFort Hancock Formation
Thickness88.3 ft (26.9 m)
Lithology
PrimarySandstone
OtherCaliche
Location
Coordinates31°19′N 105°41′W / 31.32°N 105.69°W / 31.32; -105.69
RegionTexas, New Mexico
CountryUnited States
Type section
Named forCamp Rice Arroyo
Named byW.S. Strain
Year defined1966
Camp Rice Formation is located in the United States
Camp Rice Formation
Camp Rice Formation (the United States)
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Camp Rice Formation is located in Texas
Camp Rice Formation
Camp Rice Formation (Texas)
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The Camp Rice Formation is a geologic formation in west Texas[1] and southern New Mexico.[2] It preserves fossils of the Pliocene-Pleistocene. These include the distinctive Tonuco Mountain Local Fauna.

Description

The formation consists of poorly cemented sandstone, conglomerate, siltstone, volcanic ash, and caliche. The color varies from pink to gray to light brown. The thickness at the type section is 88.3 ft (26.9 m), where the formation rests unconformably on the Fort Hancock Formation. The formation is capped by caliche that forms steep slopes. Where the caliche is eroded away, the underlying strata form badlands. The formation is found throughout the Hueco Basin[1] and Mesilla Basin.[2] Outcrops at the Tonuco Uplift northwest of Las Cruces, New Mexico, are unusually well cemented.[3] In the southern Rio Grande rift, the formation contains numerous calcic paleosols (preserved soil layers formed in an arid climate).[4]

The formation is interpreted as fluvial deposits following integration of the ancestral Rio Grande through the region.[2] A piedmont facies is found in addition to the axial river facies in southern New Mexico.[3]

Stable isotope data from the formation is consistent with a gradual warming trend in the latest Pliocene and early Pleistocene, with a generally drier climate but increased summer precipitation.[5]

Fossils

Mammals

Name Species Locality Material Notes Images
Camelidae[1] Indeterminate A camel relative
Perrisodactyla[1] Indeterminate A perissodactyl
Glyptodontinae[1] Indeterminate A glyptodont
Equus E. sp.[2] An equid
E. scotti[6] Tonuco Mountain A horse
E. simplicidens[6] A relative of zebras and donkeys
Nannippus[6] N. peninsulatus A three-toed equid
Mammuthus M. sp.[2]
Woolly mammoth
Cuvieronius C. sp.[2] A gomphothere
C. cf. tropicus[7] A complete skull
Tapirus[6] T. sp. Tonuco Mountain A mandible
Malayan tapir
Leporidae Indeterminate A rabbit or hare
Taxidea[6] T. sp. A badger
The modern American badger
Borophagus[6] B. sp. A borophagine canid
B. secundus
Canis C. lepophagus[6] A canine canid
Rhynchotherium[6] R. sp.
Camelops[6] C. sp. A large undescribed species
Camelops hesternus
Hemiauchemia H. sp.[6] A camelid
H. macrocephala
H. blancoensis[6]
Platygonus P. bicalcaratus[6] A peccary
P. compressus

Reptiles

Name Species Locality Material Notes Images
Gecholone[1] G. sp. A tortoise
Modern Indian star tortoise
Kinosternon[6] K. sp. Tonuco Mountain A mud turtle
Modern Eastern mud turtle
Gopherus[6] G. sp. A tortoise
Modern gopher tortoise
Hesperotestudo[6] H. sp. A turtle
H. sp.

Birds

Name Species Locality Material Notes Images
Anatidae[6] Indeterminate Tonuco Mountain A water bird

History

The formation was first named by W.S. Strain in 1966 for exposures near Camp Rice Arroyo in the Rio Grande valley of west Texas.[1] J.W. Hawley and coinvestigators recommended assigning the formation to the Santa Fe Group in 1969.[2]

Because the exposures of the formation in the Jornada del Muerto basin are relatively undisturbed by human activities, they have been used to test models of floodplain development in a tectonically active basin.[8]

See also

Notes

References