Wheeler Shale

The Wheeler Shale (named by Charles Walcott) is a Cambrian (c. 507 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 Konzentrat-Lagerstätte. Varied soft bodied organisms are locally preserved, a fauna (including Naraoia, Wiwaxia and Hallucigenia) and preservation style (carbonaceous film) normally associated with the more famous Burgess Shale.[3] As such, the Wheeler Shale also represents a Konservat-Lagerstätten.[4]

Wheeler Shale
Stratigraphic range:
Middle Cambrian
~507 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
Coordinates39.25°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

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
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

Arachnomorpha
  • Alalcomenaeus cambrius - megacheiran; or alalcomenaeid
  • Dicranocaris guntherorum - megacheiran; or alalcomenaeid
  • unnamed 'Molli Sonia symmetrica'
  • Leanchoilia superlata - megacheiran
  • Sidneyia inexpectans - merostomoid

Trilobita
  • Naraoia compacta - naraoiid nectaspid
  • Hypagnostus parvifrons - agnostid
  • Peronopsis amplaxis - peronopsid agnostid
  • Peronopsis bidens
  • Peronopsis fallax
  • Peronopsis gaspensis
  • Peronopsis intermedius
  • Peronopsis interstrictus
  • Peronopsis montis
  • Peronopsis segmentis
  • Ptychagnostus atavus (= Acidusus atavus) - ptychagnostid agnostid
  • Ptychagnostus germanus
  • Ptychagnostus gibbus
  • Ptychagnostus intermedius
  • Ptychagnostus michaeli
  • Ptychagnostus occultatus
  • Ptychagnostus seminula
  • Glyphaspis concavus - asaphid
  • Bathyuriscus fimbriatus - dolichometopid corynexochid
  • Bathyuriscus sp.
  • Kootenia sp. - dorypygid corynexochid, perhaps a synonym of Olenoides
  • Olenoides expansus - dorypygid corynexochid
  • Olenoides nevadensis
  • Olenoides serratus
  • Tonkinella breviceps
  • Zacanthoides divergens - zacanthoidid corynexochid
  • Zacanthoides sp.
  • Altiocculus harrisi - ptychopariid (specific name may be confused with Alokistocare)
  • Alokistocare harrisi - alokistocarid ptychopariid
  • Asaphiscus wheeleri - ptychopariid; second-most common species in the formation
  • Bathyocos housensis - ptychopariid
  • Bolaspidella drumensis
  • Bolaspidella housensis
  • Bolaspidella sp.
  • Bolaspidella wellsvillensis
  • Brachyaspidion microps
  • Brachyaspidion sulcatum
  • Cedaria minor - known from the Warrior Formation
  • Elrathia kingii - alokistocarid ptychopariid
  • Elrathia sp.
  • Elrathina wheeleri = Ptychoparella wheeleri? - ptychopariid
  • Jenkinsonia varga
  • Modocia brevispina
  • Modocia laevinucha
  • Modocia typicalis
  • Ptychoparella sp. - ptychopariid
  • Ptychoparella wheeleri
  • Spencella sp. - ptychopariid

Brachiopoda
  • Acrothele subsidua

Chordata

Cnidaria

Mollusca

Echinodermata

Porifera

Priapulida

Unclassified

References
  1. Johnson, Kirk; Troll, Ray (2007), Cruising the fossil freeway: An epoch tale of a scientist and an artist on the ultimate 5,000-Mile paleo road trip, Golden, CO.: Fulcrum Publishing, ISBN 978-1-55591-451-6
  2. Robert R. Gaines; Mary L. Droser (2003), "Paleoecology of the familiar trilobite Elrathia kingii: An early exaerobic zone inhabitant" (pdf), Geology, 31 (11): 941–4, Bibcode:2003Geo....31..941G, 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, Bibcode:2008Geo....36..755G, doi:10.1130/G24961A.1
  4. Gaines, R; Kennedy, M; Droser, M (2005), "A New Hypothesis for Organic Preservation of Burgess Shale Taxa in the Middle Cambrian Wheeler Formation, House Range, Utah", Palaeogeography, Palaeoclimatology, Palaeoecology, 220: 193–205, Bibcode:2005PPP...220..193G, 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. Gunther, L.F.; Gunther, V.G. (1981), "Some Middle Cambrian Fossils of Utah", Brigham Young University Geology Studies, 28: 1–81
  7. Brett, C. E.; Allison, P. A.; Desantis, M. K.; Liddell, W. D.; Kramer, A. (2009). "Sequence stratigraphy, cyclic facies, and lagerstätten in the Middle Cambrian Wheeler and Marjum Formations, Great Basin, Utah". Palaeogeography, Palaeoclimatology, Palaeoecology. 277: 9–33. Bibcode:2009PPP...277....9B. doi:10.1016/j.palaeo.2009.02.010.
  8. Halgedahl, S. L.; Jarrard, R. D.; Brett, C. E.; Allison, P. A. (2009). "Geophysical and geological signatures of relative sea level change in the upper Wheeler Formation, Drum Mountains, West-Central Utah: A perspective into exceptional preservation of fossils". Palaeogeography, Palaeoclimatology, Palaeoecology. 277 (1–2): 34–56. doi:10.1016/j.palaeo.2009.02.011.
  9. Gaines, R. R.; Kennedy, M. J.; Droser, M. L. (2005). "A new hypothesis for organic preservation of Burgess Shale taxa in the middle Cambrian Wheeler Formation, House Range, Utah". Palaeogeography, Palaeoclimatology, Palaeoecology. 220: 193. Bibcode:2005PPP...220..193G. doi:10.1016/j.palaeo.2004.07.034.
  10. Lieberman, B. S. (2003). "A New Soft-Bodied Fauna: the Pioche Formation of Nevada". Journal of Paleontology. 77 (4): 674–690. doi:10.1666/0022-3360(2003)077<0674:ANSFTP>2.0.CO;2. ISSN 0022-3360.
  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. Rigby, J.K. (1978), "Porifera of the Middle Cambrian Wheeler Shale, from the Wheeler Amphitheater, House Range, in western Utah", Journal of Paleontology, 52 (6): 1325–1345, doi:10.2307/1303938
  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
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