Wheeler Shale
Elrathia kingii, famed trilobite of the Wheeler Shale.
Type	Geological formation
Age	Middle Cambrian (c.507 Ma)
Thickness	100-200 metres
Lithology
Primary	Calcareous Shale
Other	Mudstone, Shaley Limestone & Limestone
Location
Named for	House Amphitheater (Geographic feature & type locality)
Named by	Charles Doolittle Walcott
Coordinates	39°15′N 113°20′W / 39.25°N 113.33°W / 39.25; -113.33
Region	House Range & Drum Range, Millard Co., west Utah
Country	USA

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-Lagerstätten. Varied soft bodied organisms are locally preserved, a fauna (e.g. Naraoia, Wiwaxia & 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]

Together with the Marjum Formation and lower Weeks Formation, the Wheeler Shale forms 490 to 610m (1,600 to 2,000ft) 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, west 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 Range, N.W. of the House Range where similar fossils and preservation are found.^[6]

Contents 1 Taphonomy & Sedimentology 2 Fauna 3 Gallery 4 References

[edit] Taphonomy & Sedimentology

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 turbitides and mudslides onto an oxygenated sea floor.^[7]

[edit] Fauna

Recorded organisms include brachiopods, primitive echinoderms, sponges, chancellorids, carpoids, eocrinoids (e.g. Gogia), trilobitomorphs, varied arthropods (e.g. Anomalocaridids, Emeraldella, Phyllocarids, trilobites), annelid & priapulid worms, jelly fish & algae.^{[9][6][10][11][12][13][14]} Intriguingly, the preservation of hard bodied trilobite remains and soft bodied animals seems to be mutually exclusive within particular horizons.^[15][4]

[edit] Gallery

Asaphiscus wheeleri, Cambrian, Wheeler shale, Utah.

Emeraldella brocki an arthropod From the Burgess Shale

[edit] References

v • d • e Burgess shale type preservation Localities Burgess shale, Chengjiang, Sirius Passet, Emu Bay, Kinzers formation, Wheeler Formation, Pioche Shale

v • d • e Modes of preservation in the Cambrian Exceptional Phosphate Orsten type · Doushantuo type Silica Bitter Springs type Carbonaceous film Burgess Shale type Pyrite Beecher's Trilobite Bed type Casts and moulds Ediacaran type Legged trilobite fossil Conventional Shelly Small shelly fossils · Conventional fossils Organic Acritarchs · Organic-walled microfossils Traces Microbialites · Trace fossils