- Emu Bay shale
infobox Rockunit
caption = North Coast of Kangaroo Island, Emu Bay
© David Simpson
type =Geological formation
prilithology =Shale
otherlithology =
namedfor =
namedby =
region = The north coast ofKangaroo Island , aroundEmu Bay andCape D'Estaing
country =South Australia ,Australia .
coordinates = coord|35|35|S|137|30|E|region:AU-SA
unitof =
subunits =
thickness =
extent =
area =
age = Lower Cambrian. ca 525 mya
Stratigraphy: Emu Bay ShaleThe Emu Bay Shale is a formation containing a major Konservat-
Lagerstätte n (fossil beds with soft tissue preservation) - one of two in the world containingRedlichiida ntrilobite s.Its mode of preservation is the same as the
Burgess shale , but the larger grain size at Emu Bay means that the quality of preservation is lower.citation
author = Glaessner, M. F.
year = 1979
journal = Alcheringa: An Australasian Journal of Palaeontology
volume = 3
issue = 1
pages = 21–31
url = http://www.informaworld.com/index/795083400.pdf
publisher = Taylor & Francis
doi = 10.1080/03115517908565437 ]Description
The Emu Bay Shale 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 oftrilobite s such as "Redlichia takooensis ", "Emuella polymera ", "Balcoracania dailyi ", and "Estaingia (=Hsuaspis) bilobata". "Balcoracania " and "Emuella " are genera of the distinctive "Redlichiina " 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 fibrouscalcium carbonate , but some including the oldest phosphatized muscle tissue and the first thus far reported from theCambrian . Mineralized soft tissues are apparently rare among Burgess-Shale-type biotas.The type section of the Emu Bay Shale crops out on the east side of Emu Bay where it conformably overlies the White Point Conglomerate. Here it yields a rich assemblage of "Hsuaspis", "Redlichia", hyolithids,
brachiopod s, and the scleritome-bearing "Chancelloria ". At the Big Gully locality (8 km east of White Point), its presumed correlative is unconformable on the White Point Conglomerate and yields soft-bodied fossils in addition to the trilobites, including the giant predator "Anomalocaris", "Isoxys", "Tuzoia", the presumed worm "Palaeoscolex ", the problematic "Myoscolex ", and a number of rarer elements. The Big Gully trilobites rarely preserve any trace of non-biomineralized tissue; a small number of specimens of "Redlichia" have been reported with antennae.See also
*
Lagerstätte - other fossil localities
*List of fossil sites "(with link directory)"References
NOTE: Much of the text of this article was used with permission of Sam Gon III from his below referenced web site, in particular from the [http://www.trilobites.info/Emu.htm Emu Bay page]
See also
References about Australian Trilobites:
External links
* [http://members.tripod.com/~Cambrian/EmuBay2 The Palaeontology of the Lower Cambrian Emu Bay Shale]
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