Wheeler Shale

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Wheeler Shale
Ma
↓
Elrathia kingii, famed trilobite of the Wheeler Shale.
TypeGeological formation
Thickness100–200 m (330–660 ft)
Lithology
PrimaryCalcareous shale
OtherMudstone, shaley limestone and limestone
Location
Coordinates39°15′N 113°20′W / 39.25°N 113.33°W / 39.25; -113.33
RegionHouse Range and Drum Mountains, Millard Co., west Utah
CountryUnited States
Type section
Named forHouse Amphitheater (Geographic feature and type locality)
Named byCharles Doolittle Walcott
Part of a series on
The Cambrian explosion
Fossil localities
Key organisms
Ediacaran biota
Burgess-type
Small shelly fauna
Evolutionary concepts
Trends
Themes

The Wheeler Shale (named by

Ma) fossil locality world-famous[1]
for prolific agnostid and
Elrathia kingii trilobite remains (even though many areas are barren of fossils)[2]
and represents a
carbonaceous film) normally associated with the more famous Burgess Shale.[3] As such, the Wheeler Shale also represents a Konservat-Lagerstätten.[4]

Together with the Marjum Formation and lower Weeks Formation, the Wheeler Shale forms 490 to 610 m (1,610 to 2,000 ft) of limestone and shale exposed in one of the thickest, most fossiliferous and best exposed sequences of Middle Cambrian rocks in North America.[5]

At the type locality of Wheeler Amphitheater, House Range, Millard County, western Utah, the Wheeler Shale consists of a heterogeneous succession of highly calcareous shale, shaley limestone, mudstone and thin, flaggy limestone.[6] The Wheeler Formation (although the Marjum & Weeks Formations are missing) extends into the Drum Mountains, northwest of the House Range where similar fossils and preservation are found.[6]

Taphonomy and sedimentology

Further information: Burgess Shale-type preservation
Asaphiscus wheeleri, Cambrian, Wheeler shale, Utah
Emeraldella brocki an arthropod From the Burgess Shale

Detailed work recognises a number of ~10 m thick lagerstätten sequences in the formation, each of which formed at a sea-level high stand[7] in deep water.[8] The lagerstätte were deposited by turbidities and mudslides onto an oxygenated sea floor.[7] The productive layers comprise mud and clay particles, with a tiny fraction of wind-blown quartz.[9]

Stratigraphy

The Wheeler Shale spans the Ptychagnostus atavus[10] and uppermost-Middle Cambrian Bolaspidella trilobite zones (See House Range for full stratigraphy).

Fauna

Stanleycaris sp. from Wheeler shale, originally described as Aysheaia prolata
Main article: Burgess Shale-type fauna

Incomplete list of the fauna of the Wheeler Shale:[6][11][12][13][14][15][16] (Note: the preservation of hard bodied trilobite remains and soft bodied animals seems to be mutually exclusive within particular horizons.)[4][17]


Protista

Arthropoda

Dinocaridida

Trilobita

Brachiopoda

Chordata

Cnidaria

Mollusca

Echinodermata

Porifera

Priapulida

Unclassified

References

  1. ISBN 978-1-55591-451-6
  2. doi:10.1130/G19926.1
  3. ^ Robert R. Gaines; Derek E.G. Briggs; Zhao Yuanlong (2008), "Cambrian Burgess Shale–type deposits share a common mode of fossilization", Geology, 36 (10): 755–758,
    doi:10.1130/G24961A.1
  4. ^
    doi:10.1016/j.palaeo.2004.07.034
  5. ^ Robison, R.A. (1964), "Late Middle Cambrian faunas from western Utah", Journal of Paleontology, 38 (3): 510–566
  6. ^ a b c Gunther, L.F.; Gunther, V.G. (1981), "Some Middle Cambrian Fossils of Utah", Brigham Young University Geology Studies, 28: 1–81
  7. ^
    doi:10.1016/j.palaeo.2009.02.010
    .
  8. doi:10.1016/j.palaeo.2009.02.011
    .
  9. doi:10.1016/j.palaeo.2004.07.034
    .
  10. S2CID 130145927
    .
  11. ^ Briggs, D.E.G.; Robison, R.A. (1984), Exceptionally preserved nontrilobite arthropods and Anomalocaris from the Middle Cambrian of Utah, The Paleontological Institute, The University of Kansas
  12. ^ Photos of Wheeler Shale fossils from UC Berkeley
  13. JSTOR 1303938
  14. ^ Utah's Cambrian Life from University of Kansas Natural History Museum
  15. ^ Cambrian fossils from Utah by the University of Utah
  16. ^ Comprehensive treatment from The Virtual Fossil Museum
  17. ^ Gaines, Robert R.; Droser, Mary L.; Kennedy, Martin J. (2001), "Taphonomy of soft-bodied preservation and ptychopariid Lagerstätte in the Wheeler Shale (Middle Cambrian), House Range, USA; controls and implications", PaleoBios, 21 (Suppl.2): 1–55
  18. ^
    PMID 33552709
    .
  19. S2CID 250076505
    .
  20. PMID 35135344
    .
  21. S2CID 251544727
    .
  22. PMID 27383414
    .
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