Baca Formation

The Baca Formation is a geologic formation in southern New Mexico and Arizona.[1] It preserves fossils dating back to the Eocene period.[2]

Baca Formation
Stratigraphic range: Eocene
Red beds of the Baca Formation in the Sawtooth Mountains of New Mexico
TypeFormation
UnderliesSpears Formation
OverliesMesaverde Group
Thickness694 feet (212 m)
Lithology
PrimaryConglomerate
OtherSandstone, claystone
Location
Coordinates34.332°N 107.272°W / 34.332; -107.272
RegionNew Mexico
CountryUnited States
Type section
Named forBaca Canyon
Named byR.H. Wilpolt et al.
Year defined1946
Baca Formation (the United States)
Baca Formation (New Mexico)

Description

The formation consists of coarse conglomerate, red and white sandstone, and red clay. Its total thickness is 694 feet (212 m), of which 80–140 feet (24–43 m) is conglomerate.[1] The formation rests unconformably on the Mesaverde Group and is overlain by the Oligocene Spears Formation.[2]

Fossils

The formation is relatively poor in vertebrate fossils, and only six of biostratigraphic significance have been found. These are the titanotheres Paleosyops and Manteoceras, an artiodactyl fossil trackway and Protoreodon fossil, and a small mammalian fauna at Mariano Mesa. The titanotheres are characteristic of the Bridgerian age while the trackways indicate a late Eocene age or younger.[2]

History of investigation

The formation was first described by R.H. Wilpolt and his coinvestigators in 1946 and named for exposures in Baca Canyon in the Sacramento Mountains.[1]

See also

Footnotes

References

  • Lucas, Spencer G.; Schoch, Robert M.; Manning, Earl; Tsentas, Costgas (1981). "The Eocene biostratigraphy of New Mexico". Geological Society of America Bulletin. 92 (12): 951. doi:10.1130/0016-7606(1981)92<951:TEBONM>2.0.CO;2.
  • Wilpolt, R.H.; MacAlpin, A.J.; Bates, R.L.; Vorbe, George (1946). "Geologic map and stratigraphic sections of Paleozoic rocks of Joyita Hills, Los Pinos Mountains, and northern Chupadera Mesa, Valencia, Torrance, and Socorro Counties, New Mexico". U.S. Geological Survey Oil and Gas Investigations Preliminary Map. OM-61. Retrieved 31 July 2020.
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