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Wheeler Shale

{{Short description|Geologic formation in Utah notable for trilobite fossils}}

{{Infobox rockunit

| image = ElrathiakingiUtahWheelerCambrian.jpg

| caption = Elrathia kingii, famed trilobite of the Wheeler Shale.

| type = Geological formation

| period = Cambrian

| age =
Middle Cambrian
~{{fossil range|507}}

| prilithology = Calcareous shale

| otherlithology = Mudstone, shaley limestone and limestone

| namedfor = House Amphitheater (Geographic feature and type locality)

| namedby = Charles Doolittle Walcott

| region = House Range and Drum Mountains, Millard Co., west Utah

| country = United States

| coordinates = {{coord|39.25|N|113.33|W|region:US-UT_type:landmark_source:dewiki}}

| unitof =

| subunits =

| thickness = {{convert|100|-|200|m|ft|abbr=on}}

| extent =

| area =

}}

{{CEXNAV}}

The Wheeler Shale (named by Charles Walcott) is a Cambrian ({{circa}} 507 Ma) fossil locality world-famous{{citation

|last1=Johnson

|first1=Kirk

|last2=Troll|first2= Ray|year=2007

|title=Cruising the fossil freeway: An epoch tale of a scientist and an artist on the ultimate 5,000-Mile paleo road trip|publisher=Fulcrum Publishing |location= Golden, CO. |isbn = 978-1-55591-451-6}}

for prolific agnostid and Elrathia kingii trilobite remains (even though many areas are barren of fossils){{Citation

|journal=Geology

|title=Paleoecology of the familiar trilobite Elrathia kingii: An early exaerobic zone inhabitant

|author1=Robert R. Gaines

|author2=Mary L. Droser

|year=2003

|url=http://earthsciences.ucr.edu/docs/Gaines&Droser_2003.pdf

|volume=31

|pages=941–4

|doi=10.1130/G19926.1

|issue=11

|bibcode = 2003Geo....31..941G }}

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.

{{Citation

|journal=Geology

|title=Cambrian Burgess Shale–type deposits share a common mode of fossilization

|author=Robert R. Gaines

|author2=Derek E.G. Briggs |author3=Zhao Yuanlong

|year=2008

|doi=10.1130/G24961A.1

|volume=36

|pages=755–758

|issue=10

|bibcode=2008Geo....36..755G

}} As such, the Wheeler Shale also represents a Konservat-Lagerstätten.{{Citation

| doi = 10.1016/j.palaeo.2004.07.034

| title = A New Hypothesis for Organic Preservation of Burgess Shale Taxa in the Middle Cambrian Wheeler Formation, House Range, Utah

| year = 2005

| author = Gaines, R

| journal = Palaeogeography, Palaeoclimatology, Palaeoecology

| volume = 220

| pages = 193–205

| last2 = Kennedy

| first2 = M

| last3 = Droser

| first3 = M

| issue = 1–2

| bibcode = 2005PPP...220..193G

}}

Together with the Marjum Formation and lower Weeks Formation, the Wheeler Shale forms {{convert|490|to|610|m|ft|abbr=on}} of limestone and shale exposed in one of the thickest, most fossiliferous and best exposed sequences of Middle Cambrian rocks in North America.{{citation

|last1=Robison

|first1=R.A.

|journal = Journal of Paleontology

| year = 1964

| volume = 38

| url = http://jpaleontol.geoscienceworld.org/cgi/content/abstract/38/3/510

| pages = 510–566

| title= Late Middle Cambrian faunas from western Utah

|issue=3}}

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. 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.

Taphonomy and sedimentology

{{further|Burgess Shale-type preservation}}

Image:Asaphiscuswheelerii.jpg

Image:Emeraldella brocki.jpg]]

Detailed work recognises a number of ~10 m thick lagerstätten sequences in the formation, each of which formed at a sea-level high stand{{Cite journal| last2 = Allison| first1 = C. E.| first2 = P. A.| last3 = Desantis| last4 = Liddell| last5 = Kramer | first3 = M. K.| first4 = W. D.| first5 = A.| title = Sequence stratigraphy, cyclic facies, and lagerstätten in the Middle Cambrian Wheeler and Marjum Formations, Great Basin, Utah| journal = Palaeogeography, Palaeoclimatology, Palaeoecology| volume = 277| pages = 9–33| year = 2009| last1 = Brett| issue = 1–2| doi = 10.1016/j.palaeo.2009.02.010| bibcode = 2009PPP...277....9B }} in deep water.{{Cite journal| last3 = Brett | first1 = S. L. | first2 = R. D.| first3 = C. E.| last2 = Jarrard| first4 = P. A. | title = 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| last4 = Allison| journal = Palaeogeography, Palaeoclimatology, Palaeoecology| volume = 277| issue = 1–2| pages = 34–56 | year = 2009| last1 = Halgedahl | author-link1 = Susan Halgedahl|doi = 10.1016/j.palaeo.2009.02.011| bibcode = 2009PPP...277...34H }} The lagerstätte were deposited by turbidities and mudslides onto an oxygenated sea floor.

The productive layers comprise mud and clay particles, with a tiny fraction of wind-blown quartz.{{Cite journal | last1 = Gaines | first1 = R. R. | last2 = Kennedy | first2 = M. J. | last3 = Droser | first3 = M. L. | title = A new hypothesis for organic preservation of Burgess Shale taxa in the middle Cambrian Wheeler Formation, House Range, Utah | doi = 10.1016/j.palaeo.2004.07.034 | journal = Palaeogeography, Palaeoclimatology, Palaeoecology | volume = 220 | pages = 193–205 | year = 2005 | issue = 1–2 | bibcode = 2005PPP...220..193G }}

Stratigraphy

The Wheeler Shale spans the Ptychagnostus atavus{{Cite journal| last1 = Lieberman | first1 = B. S.| title = A New Soft-Bodied Fauna: the Pioche Formation of Nevada| journal = Journal of Paleontology| volume = 77| issue = 4| pages = 674–690| year = 2003| issn = 0022-3360| doi = 10.1666/0022-3360(2003)077<0674:ANSFTP>2.0.CO;2| s2cid = 130145927}} and uppermost-Middle Cambrian Bolaspidella trilobite zones (See House Range for full stratigraphy).

Fauna{{anchor|Burgess Shale-type fauna}}

Image:Stanleycaris_sp._KUMIP_153923.png prolata]]

{{main|Burgess Shale-type fauna}}

Incomplete list of the fauna of the Wheeler Shale:{{citation

|last1=Gunther

|first1=L.F.

|last2=Gunther

|first2=V.G.

|year=1981

|title=Some Middle Cambrian Fossils of Utah

|journal=Brigham Young University Geology Studies

|volume=28

|pages=1–81}}{{Citation

|author1=Briggs, D.E.G. |author2=Robison, R.A. | title = Exceptionally preserved nontrilobite arthropods and Anomalocaris from the Middle Cambrian of Utah

| year = 1984

| url = http://kuscholarworks.ku.edu/dspace/handle/1808/3656

| publisher = The Paleontological Institute, The University of Kansas}}[http://www.ucmp.berkeley.edu/cambrian/house.html Photos of Wheeler Shale fossils from UC Berkeley]{{citation

|last1=Rigby

|first1=J.K.

|journal = Journal of Paleontology

| year = 1978

| volume = 52

| pages = 1325–1345

| title= Porifera of the Middle Cambrian Wheeler Shale, from the Wheeler Amphitheater, House Range, in western Utah

|issue= 6

|jstor=1303938

}}[http://www.kumip.ku.edu/cambrianlife Utah's Cambrian Life from University of Kansas Natural History Museum][http://www.earth.utah.edu/utahfossil.html Cambrian fossils from Utah by the University of Utah][http://www.fossilmuseum.net/Cambrian-Explosion/Utah-Cambrian-Explosion.htm Comprehensive treatment from The Virtual Fossil Museum]

(Note: the preservation of hard bodied trilobite remains and soft bodied animals seems to be mutually exclusive within particular horizons.){{citation

| last1 = Gaines

| first1=Robert R.

| last2= Droser

| first2= Mary L.

| last3= Kennedy

|first3= Martin J.

|year= 2001

|title=Taphonomy of soft-bodied preservation and ptychopariid Lagerstätte in the Wheeler Shale (Middle Cambrian), House Range, USA; controls and implications

|journal= PaleoBios

| volume= 21 (Suppl.2)

| pages=1–55

|url=http://www.ucmp.berkeley.edu/napc/abs9.html}}

=Protista=

=Arthropoda=

== Dinocaridida ==

  • Amplectobelua cf. A. stephenensis – radiodont{{Cite journal |last1=Pates |first1=Stephen |last2=Lerosey-Aubril |first2=Rudy |last3=Daley |first3=Allison C. |last4=Kier |first4=Carlo |last5=Bonino |first5=Enrico |last6=Ortega-Hernández |first6=Javier |date=2021-01-19 |title=The diverse radiodont fauna from the Marjum Formation of Utah, USA (Cambrian: Drumian) |journal=PeerJ |language=en |volume=9 |pages=e10509 |doi=10.7717/peerj.10509 |issn=2167-8359 |pmc=7821760 |pmid=33552709 |doi-access=free }}
  • Anomalocarididae gen. et sp. nov. - radiodont
  • Buccaspinea cooperi? - radiodont
  • Caryosyntrips durus - radiodont
  • Caryosyntrips serratus - radiodont
  • Peytoia nathorsti - radiodont
  • Pahvantia hastata - radiodont
  • Stanleycaris sp. - radiodont
  • Utahnax vannieri - kerygmachelid lobopodian, possibly from Marjum Formation{{Cite journal |last1=Lerosey‐Aubril |first1=Rudy |last2=Ortega‐Hernández |first2=Javier |date=2022 |editor-last=Zhang |editor-first=Xi‐Guang |title=A new lobopodian from the middle Cambrian of Utah: did swimming body flaps convergently evolve in stem‐group arthropods? |url=https://onlinelibrary.wiley.com/doi/10.1002/spp2.1450 |journal=Papers in Palaeontology |language=en |volume=8 |issue=3 |doi=10.1002/spp2.1450 |s2cid=250076505 |issn=2056-2799|url-access=subscription }}
  • Utaurora comosa - opabiniid{{Cite journal |last1=Pates |first1=Stephen |last2=Wolfe |first2=Joanna M. |last3=Lerosey-Aubril |first3=Rudy |last4=Daley |first4=Allison C. |last5=Ortega-Hernández |first5=Javier |date=2022-02-09 |title=New opabiniid diversifies the weirdest wonders of the euarthropod stem group |journal=Proceedings of the Royal Society B: Biological Sciences |volume=289 |issue=1968 |pages=20212093 |doi=10.1098/rspb.2021.2093 |pmc=8826304 |pmid=35135344}}

==Trilobita==

=Brachiopoda=

=Chordata=

=Cnidaria=

=Mollusca=

=Echinodermata=

=Porifera=

=Priapulida=

=Unclassified=

  • Hallucigenia sparsa - hallucigeniid lobopod
  • Allonnia cf. tintinopsis - a chancelloriid{{Cite journal |last1=Foster |first1=John R. |last2=Howells |first2=Thomas F. |last3=Sroka |first3=Steven D. |date=2022 |title=First record of the chancelloriid Allonnia from the middle Cambrian Wheeler Formation (Drumian, Miaolingian) of western Utah |url=https://escholarship.org/uc/item/03b3j605 |journal=PaleoBios |language=en |volume=39 |issue=4 |doi=10.5070/P939455661 |s2cid=251544727 |issn=0031-0298|doi-access=free }}
  • Chancelloria pentacta - chancelloriid
  • Eldonia sp. - eldoniid cambroernid
  • Skeemella clavula - Possible vetulicolian
  • Hylolithellus sp. - annelid?
  • Wiwaxia corrugata - halwaxiid? lophotrochozoan
  • Yuknessia simplex - pterobranch
  • Margaretia dorus - tube associated with the hemichordate Oesia{{Cite journal|last1=Nanglu|first1=Karma|last2=Caron|first2=Jean-Bernard|last3=Conway Morris|first3=Simon|last4=Cameron|first4=Christopher B.|date=2016-07-07|title=Cambrian suspension-feeding tubicolous hemichordates|journal=BMC Biology|volume=14|pages=56|doi=10.1186/s12915-016-0271-4|issn=1741-7007|pmc=4936055|pmid=27383414 |doi-access=free }}

References

{{reflist|2}}

{{Burgess shale type preservation}}

{{Cambrian preservational modes}}

Category:Geologic formations of Utah

Category:Cambrian System of North America

Category:Cambrian geology of Utah

Category:Paleontology in Utah