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User:Gongoozler123/Rampart Cave

< User:Gongoozler123
Rampart Cave
Interior view of Rampart Cave, detail of sloth dung, sept 1938. NPS.
LocationColumbine Falls, Arizona, USA
Discovery1936, CCC
HazardsFire in 1976
AccessClosed

Rampart Cave is a cave located at 36°05′56″N 113°55′57″W / 36.09889°N 113.93250°W / 36.09889; -113.93250[1] in Grand Canyon National Park (GRCA), Mohave County, Arizona, on the south bank of the Colorado River, 50 mi (80 km) east of Boulder City, Nevada.[2]. Together with the nearby Muav Caves, Rampart Cave was within the Lake Mead National Recreation Area but both caves were incorporated into the GRCA in January 1975.[3]

It is an extensive and well-protected cave with a unique and rare repository of Late Pleistocene vertebrate remains, and no documented traces of man.[2] The primary deposits in the cave are dry dung from Nothrotheriops shastensis (Shasta ground sloth) — the first, smelliest, and ornierest hermits of Grand Canyon — from which bones and soft tissue remnants have also been found, but remains of other extinct and extant mammals, reptiles, and birds have also been recovered. The cave was first discovered by Civilian Conservation Corps in 1936, [...] ...most of which was destroyed by a fire in 1976.

There are two other caves near Rampart Cave:[1] Muav Caves and an unnamed cave.

dry caves of arid America have yielded unusual perishable remains of extinct Pleistocene animals such as hair dung soft tissue of ground sloths mammoths.

--other less well known collections-- six caves of the Grand Canyon [4]

The earliest report of fossils from Grand Canyon caves dates back to 1936 when NPS employee Willis Evans located a rich cave deposit of late Pleistocene fossil bones and sloth dung in Rampart Cave.[3]
Hooks
The first, smelliest and orneriest hermits of Grand Canyon were the Ground Sloth.
11,000 years old dung deposits destroyed by a careless smoker in the 1970s.[5]

Geology

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See also: Geology of the Grand Canyon area

The cave was formed in ...

Middle Cambrian Muav Limestone[6] of the Tonto Group[7]

  • Dark-gray, light-gray, brown, and orangered, cliff-forming limestone, dolomite, and calcareous mudstone.
    • Includes, in descending order, unclassified dolomites, and Havasu, Gateway Canyon, Kanab Canyon, Peach Springs, Spencer Canyon, and Rampart Cave Members of McKee and Resser (1945). These members consist of fine- to medium-grained, thin to thick-bedded, mottled, fossiliferous, silty limestone, limestone, and dolomite.
    • Three unnamed slope-forming siltstone and shale units of Bright Angel Shale lithology are intertongued between cliff-forming members of Muav Limestone. These unnamed siltstone and shale units are green and purplish-red, micaceous siltstone, mudstone, and shale, and thin brown sandstone.
    • Contact with the underlying Bright Angel is gradational and lithology dependent. Contact is arbitrarily marked at base of lowest prominent cliff-forming limestone of Rampart Cave Member of the Muav in western half of map area[8], and of Peach Springs–Kanab Canyon Members of the Muav in eastern half of map area.
    • All members of the Muav thicken from east to west across map area. However, the Peach Springs, Spencer Canyon, and Rampart Cave change to purple-red and green siltstone/shale facies of the Bright Angel in eastern half of map area, where they are included as part of the Bright Angel.
    • Intertonguing and facies change relationships between the Muav and Bright Angel produce variable thickness trends. Overall, the Muav thickens from about 350 ft (107 m) in eastern part of map area to about 600 ft (183 m) in western part.

[6]

Tonto Group: Muav Limestone averages 505 million years old and is made of grey, thin-bedded limestone that was deposited farther offshore from calcium carbonate precipitates. It is fossil poor yet trilobites and brachiopods have been found in it. The western part of the canyon has a much thicker sequence of Muav than the eastern part. The Muav is a cliff-former, 136 to 827 feet (41 to 252 m) thick.
On the basis of the stratigraphic positions of selected springs in the Grand Canyon and along the Grand Wash Cliffs, Twenter identified the Rampart Cave Member of the Muav Limestone (Figure 3) as the best potential aquifer under the Hualapai Plateau. He selected the three target drilling areas shown on Figure 1, which were located on the basis of (1) sufficient surrounding surface areas to insure recharge to the sites, and (2) drilling depths of less than 1,000 feet. Twenter recognized the importance of tectonic fracturing on the enhancement of permeabilities, but his site selections did not include known faulted or folded rocks.

[9]

Paleofauna

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Fossils from many now extinct North American mammals:

Mammals

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The youngest radiocarbon dates on Shasta ground sloths coincide in age with youngest dates on machairodont cat (Smilodon), horse (Equus), and bison (Bison antiquus) in Southern California. Harrington's goat vanished together with this group at a time when local plant communities were experiencing considerable turnover and when Clovis big game hunters were active in the Southwest.

[4]

Ground sloth

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Skull of ground sloth Nothrotherium excavated in Rampart Cave in September 1936. (NPS).

The first, smelliest and orneriest hermits of Grand Canyon were the Ground Sloth. The cave served as a convenient stop for Shasta ground sloths until 11,000 years ago when the cave sunk into the Muav Limestone Grand Wash Cliffs [10]

ground sloth dung has "accumulated to a depth of over 20 ft (6.1 m) in places and covered an area of 4,700 sq ft (440 m2) [2]

Over 200 bones of N. shastensis have been found in Rampart Cave. [3]

Sloth dung samples have radiocarbon dated to older than 40,000 BP to younger than 11,000 BP. 72 genera of plants have been found and pollen from these plants revealed seasonal variation in the sloth’s diet. [3]

Harrington's goat

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Bones of various animals collected from rampart cave. Includes mountain goat horns and possibly camel bones. Sept 1936. Nps.
  • Harrington's mountain goat (Oreamnos harrington) occupied the Grand Canyon for at least 19,000 years before becoming extinct 11,160±125 BP concurrently with the ground sloth.

Compared to living mountain goats (Oreamnons americanus), Harrington's mountain goat was small, with a more robust mandible, a distinctive palate, and larger dung pellets. This extinct goat and the ground sloth once occupied the same region and the same cave, but it is hard to imagine two more divergent large herbivores:

  Goat Sloth
Anatomy and physiology Digitigrade, gracile, and presumably highly mobile in rough terrain Plantigrade and ponderous
Social behaviour Living goats are gregarious Solitary
Feeding behaviour Grazing ruminants Browsing monogastrics
Ancestry Holartic and boreal Neotropical

Notwithstanding these differences, they apparently went extinct at the same time and for the same reason. Conceivably, the mountain goat lingered to a slightly later time (~10,000 years BP) around Rampart Cave. [4]

Mountain lion

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Upper jaw of mountain lion collected in Rampart Cave. Oct 1936. NPS

Mountain lion (i.e. cougar (Puma concolor)

Packrat

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Packrat deposits are well known from the cave.
One such deposit is a 13 in (33 cm) unindurated (uncemented) “seam” separating the two major dung layers in the cave. The seam is made up of plant material such as twigs and other macrofossils that are “perfectly preserved”.
Deposited by packrats between 24,000 and 14,000 years BP, the seam may constitute the largest Pleistocene packrat deposit ever found.
Thirty additional indurated (cemented) middens were found both in and around Rampart Cave.

[3]

Birds

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California Condor

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bird remains at 30-57 inches down

Probably the first time a Condor has been reported from Arizona.

bird remains in fourteen small packets (fragment of a hawk pelvis, possibly Buteo jamaicensis), all other contain condor bones, adult bones equaled those of recent birds

most bones highly fragmented, probably because of trampling by ground sloths, ... some nibbling by rodents.

  • carpometacarpus, phalanges, pollex, a claw, innominate with acetabulum, synsacrum, fragment of ulna, coracoid of nestling bird.

[2]

Other birds

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[2]

Paleoflora

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Colorado Pinyon

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nearly all populations are in Arizona, New Mexico, Colorado, and Utah [...] north of the range of Texas Pinyon (P. remota
...was a dominant woodland component before 38 000 to 10 975 BP; became occasional to rare 10,040 to 9,515 BP.
  • Several studies have been undertaken of natural hybridization and introgression involving P. edulis and P. monophylla. Materials similar to those found in extant zones of hybridization have been found in middens at Rampart Cave in Arizona dated at 12 650 BP, and at Desert Almond Canyon, a lower Grand Canyon site dated at 12 600 BP.

[12]

Sixty types of plants were identified from within packrat middens, aiding in paleoecological reconstruction of the Rampart Cave area. Additional plant material from packrat middens yielded dates ranging from 18,890 (Fraxinus anomala twigs) to 9,520 years B.P. (Agave utahensis).[3]
See also: Paleoparasitology

See also

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References

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  1. ^ a b Mount, Jack D. (1992). "Caves of Arizona: an Index of the Topographic Maps on Which They are Located". University of Arizona. (PDF)
  2. ^ a b c d e f Miller, Loye (1960). "Condor Remains from Rampart Cave, Arizona". The Condor. 62 (1): 70. (PDF)
  3. ^ a b c d e f Santucci, Vincent L.; Kenworthy, Jason; Kerbo, Ron (September 2001). "An Inventory of Paleontological Resources Associated with National Park Service Caves" (PDF). NPS. pp. 16–19.{{cite web}}: CS1 maint: multiple names: authors list (link) (including images from the 1976 fire)
  4. ^ a b c Mead; et al. (February 1986). "Extinction of Harrington's mountain goat" (PDF). PNAS. 83: 836–839. {{cite journal}}: Explicit use of et al. in: |author= (help)
  5. ^ NPS: In the 1970s many fossils were lost due to careless visitors leaving a fire burning in Rampart Cave.
  6. ^ a b "Colorado River Basin Stratigraphy: Muav Limestone". USGS. 2006. Retrieved September 2010. {{cite web}}: Check date values in: |accessdate= (help)
  7. ^ "Colorado River Basin Stratigraphy: Tonto Group". USGS. 2006. Retrieved September 2010. {{cite web}}: Check date values in: |accessdate= (help)
  8. ^ Billingsley, George H. (2000). "Geologic Map of the Grand Canyon 30' x 60' Quadrangle, Coconino and Mohave Counties, Northwestern Arizona". USGS.
  9. ^ Huntoona, Peter W. (November–December 1977). "Cambrian Stratigraphic Nomenclature and Ground-Water Prospecting Failures on the Hualapai Plateau, Arizona". Ground Water. 15 (6).{{cite journal}}: CS1 maint: date format (link) (Google cache)
  10. ^ Hutchinson, Robert; Clay, Willard (1995). Grand Canyon National Park: A Photographic Natural History. BrownTrout Publishers. ISBN 1563136112.{{cite book}}: CS1 maint: multiple names: authors list (link)
  11. ^ Schmidt, Gerald D.; Duszynski, Donald W.; Martin, Paul S. (1992), Parasites of the Extinct Shasta Ground Sloth, Nothrotheriops shastensis, in Rampart Cave, Arizona, J. Parasitol., 78(5), 1992, p. 811-816, American Society of Parasitologists
  12. ^ Richardson, David M. (2000). Ecology and biogeography of Pinus. Cambridge University Press. ISBN 0521789109.
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{{paleo-site-stub}} {{Arizona-geo-stub}}

Category:Caves of Arizona Category:Paleontological sites of North America

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