Locality: Kangaroo Island, Emu Bay & Cape D'Estaing, South Australia
Stratigraphy: Emu Bay Shale Formation
Age: Lower Cambrian. ca 525 mya
The Emu Bay Shale Formation of Kangaroo Island,
South Australia is Australia's only known Burgess-Shale-type
Konservat-Lagerstätte, and includes faunal elements such as Anomalocaris,
Tuzoia, Isoxys, Xandarella, and Primicaris, in
common with other Burgess-Shale-type assemblages, particularly the Chengjiang
Fauna in China, the closest palaeogeographically, although somewhat older.
The site is also the source of magnificent specimens of trilobites such as
Redlichia takooensis, Emuella polymera, Balcoracania dailyi,
and Estaingia (=Hsuaspis) bilobata. Balcoracania and Emuella
are members of the distinctive redlichiine superfamily Emuelloidea, known
for numerous segments (over 60 in large Balcoracania specimens), and
so far entirely restricted to Australia.
The depositional environment of the majority of Burgess-Shale-type assemblages is outer shelf, deeper water. The Emu Bay shale in contrast, appears to represent relatively shallow water deposition, indicating that soft tissue preservation occurred in a range of environmental settings during the Cambrian. Some Emu Bay fossils display extensive mineralization of soft tissues, most often of blocky apatite or fibrous calcium carbonate, but some including the oldest phosphatized muscle tissue and the first thus far reported from the Cambrian. Mineralized soft tissues are apparently rare among Burgess-Shale-type biotas.
|Location of the Emu Bay Shale lagerstatte
||Locality of Emu Bay Shale during the
The Emu Bay Shale was initially considered late Early Cambrian in age, but this was calibrated by data on the Early Cambrian in China. Occurrence of R. takooensis and species of Hsuaspis matches the Tsanglangpuian in the Chinese sequence, and contemporary South Australian faunas correlate with the Botomian of Siberia. So the age of the Emu Bay Shale lies between the Middle Cambrian Burgess Shale, and the upper Atdabanian Chengjiang of China. Below are four representative species from the Emu Bay Shale Formation:
Paterson & Jago 2006
Hagadorn, J.W. 2002. Burgess Shale-type Localities: The global picture.
in: Bottjer, D.J., W. Etter, J.W. Hagadorn & C.M. Tang, eds., Exceptional Fossil Preservation -- A Unique View on the
Evolution of Marine Life. 403 pp. Columbia University Press.
Nedin, C., 1995. The Emu Bay Shale, a Lower Cambrian fossil Lagerstätte, Kangaroo Island, South Australia. Memoirs of the Association of Australasian Palaeontologists, 18, 31-40.
Paterson, J.R. & G.D., Edgecombe. 2006. The Early Cambrian trilobite family Emuellidae Pocock, 1970: Systematic position and revision of Australian species. Journal of Paleontology 80(3): 496-513.
Paterson, J.R. & J.B. Jago. 2006. New trilobites from the Lower Cambrian Emu Bay Shale Lagerstätte at Big Gully, Kangaroo Island, South Australia. Memoirs of the Association of Australasian Palaeontologists 32: 43-57.
Trilobites of South Australia,
a website by Dave Simpson
Australian Trilobites: A Species List and Bibliography by Greg Edgecombe and the Australian Museum