Gogo Formation
{{Short description|Lagerstätte formation in the Kimberley, Western Australia}}
{{Use Australian English|date=November 2013}}
{{Use dmy dates|date=April 2022}}
{{Infobox rockunit
| name = Gogo Formation
| period = Frasnian
| age = {{fossilrange|Frasnian|Frasnian|Frasnian}}
| image =
| imagesize =
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| type = Geological formation
| prilithology = Shale, Siltstone
| otherlithology = Limestone
| unitof =
| subunits =
| underlies = Virgin Hills Formation
| overlies = Unconformity with Prices Creek Group
| thickness = Up to {{convert|700|m|ft|abbr=on}}
| area =
| map = {{Location map+ | Australia#Western Australia
| relief = 1
| width = 250
| float = center
| places =
{{Location map~ | Australia#Western Australia
| lat_deg = -18.3
| lon_deg = 126.5
| mark = Gold pog.svg
| marksize = 12
}}
}}
| map_caption =
| location = Kimberley, Western Australia
| coordinates = {{Coord|18.3|S|126.5|E|display=inline,title}}
| paleocoordinates = {{coord|16.7|S|136.7|E|display=inline}}
| region = Western Australia
| country = Australia
| extent =
| namedfor = Gogo Station
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| region_ts =
| country_ts =
| thickness_ts = ~{{convert|425|m|ft|abbr=on}}
}}
The Gogo Formation in the Kimberley region of Western Australia is a Lagerstätte that exhibits exceptional preservation of a Devonian reef community. The formation is named after Gogo Station, a cattle station where outcrops appear and fossils are often collected from,[http://www.dpc.wa.gov.au/GuidelinesAndPolicies/SymbolsOfWA/Pages/FossilEmblemGogoFish.aspx "The Fossil Emblem of Western Australia"] {{Webarchive|url=https://web.archive.org/web/20160522203124/https://www.dpc.wa.gov.au/GuidelinesAndPolicies/SymbolsOfWA/Pages/FossilEmblemGogoFish.aspx |date=22 May 2016 }} Accessed 16 August 2012. as is nearby Fossil Downs Station.
History
The reef, which now stands up abruptly in the western Australian desert (as the Windjana Limestone), was first identified in 1940 by paleontologist Curt Teichert, who discovered the first fossil fish from the region.{{cite book |author-link=John A. Long (paleontologist) |first=John |last=Long |title=Swimming in Stone: the Amazing Gogo Fossils of the Kimberley |location=Fremantle, W.A. |publisher=Fremantle Arts Centre |year=2007}}
Sedimentology
Unweathered sections of the Gogo Formation are made of siltstone, shale and calcarenite with numerous limestone concretions. These concretions are resistant to weathering, producing extensive nodule fields on the ground in areas where the surrounding rock has eroded away.{{cite web|url=http://dbforms.ga.gov.au/pls/www/geodx.strat_units.sch_full?wher=stratno=7476 |title=Australian Stratigraphic Names Database |publisher=Australian Government Geoscience Australia |date=2010-09-29 |accessdate=2011-03-28}}
The Gogo sediments represent deep, hypoxic seafloor deposits in the vicinity of a large tropical reef composed primarily of algae and stromatoporoids during the Frasnian faunal stage of the Late Devonian.{{Cite web |url=http://palaeo.gly.bris.ac.uk/palaeofiles/lagerstatten/Gogo/index.html |title=Gogo Reef Formation |access-date=28 May 2008 |archive-url=https://web.archive.org/web/20180307165801/http://palaeo.gly.bris.ac.uk/palaeofiles/lagerstatten/Gogo/index.html |archive-date=7 March 2018 |url-status=dead }} Associated stratigraphic units which comprise this ancient reef system are the Windjana Formation (the actual reef structures), Pillara Limestone (reef platform) and the Sadler Formation (fore-reef deposits).
Deposition
Fossil preservation
The fossils of the Gogo Formation display three-dimensional soft-tissue preservation of tissues as fragile as nerves and embryos with umbilical cords.{{Cite journal |last1=Long |first1=J. A. |last2=Trinajstic |first2=K. |author-link2=Kate Trinajstic |year=2010 |title=The Late Devonian Gogo Formation Lägerstatte of Western Australia: Exceptional Early Vertebrate Preservation and Diversity |journal=Annual Review of Earth and Planetary Sciences |volume=38 |pages=255–279 |bibcode=2010AREPS..38..255L |doi=10.1146/annurev-earth-040809-152416}} Over fifty species of fish have been described from the formation, and arthropods, including phyllocarids{{Cite journal| last1 = Ian Rolfe | first1 = W. D.| title = Phyllocarid Crustacean Fauna of European Aspect from the Devonian of Western Australia| journal = Nature| volume = 209| pages = 192| year = 1966| doi = 10.1038/209192a0|bibcode = 1966Natur.209..192R | issue=5019| s2cid = 129316791}} and eurypterids{{Cite journal| last1 = Tetlie | first1 = O. E.| last2 = Braddy | first2 = S. J.| last3 = Butler | first3 = P. D.| last4 = Briggs | first4 = D. E. G.| title = A New Eurypterid (Chelicerata: Eurypterida) from the Upper Devonian Gogo Formation of Western Australia, with a Review of the Rhenopteridae| journal = Palaeontology| volume = 47| issue = 4| pages = 801| year = 2004| doi = 10.1111/j.0031-0239.2004.00390.x| bibcode = 2004Palgy..47..801T| doi-access = free}} are similarly well-preserved. Nautiloids, goniatites and tentaculids are also known from the formation, but their soft tissue is not preserved.
The calcareous concretions formed around objects from the shallow reef areas which sank into the deep anoxic basins. The concretions sometimes contain the remains of fish, whose bodies are often preserved complete in three-dimensions due to rapid encasement and the slow rate of decay in the oxygen-poor surroundings. By repeated baths in a dilute acid solution, the matrix is dissolved away via a process of acid etching to reveal delicate fish fossils, some retaining impressions of soft tissues.
The discovery of Materpiscis, a placoderm preserved with an embryonic juvenile still attached by its umbilical cord, has revealed that at least some placoderms gave birth to live young.[http://www.news.com.au/perthnow/story/0,21598,23776422-2761,00.html "Aussie fish fossil gives birth to history"] Accessed 29 May 2008.
Fossil content
=Placodermi=
= Actinopterygii =
= Chondrichthyes =
= Acanthodians =
= Sarcopterygii =
= Conodonta =
| class="wikitable sortable"
! Genus !! Species !! Notes | ||
| rowspan="4" | Polygnathus | P. varca | align="center" | {{Cite journal |last1=Glenister |first1=Brian F. |last2=Klapper |first2=Gilbert |date=1966 |title=Upper Devonian Conodonts from the Canning Basin, Western Australia |url=https://www.jstor.org/stable/1301879 |journal=Journal of Paleontology |volume=40 |issue=4 |pages=777–842 |jstor=1301879 |issn=0022-3360}} |
| P. normalis | align="center" | | |
| P. asymmetrica asymmetrica | align="center" | | |
| P. asymmetrica ovalis | align="center" | | |
| Playfordia | P. primitiva | align="center" | |
| rowspan="2" | Gnamptognathus | G.? lipperti | align="center" | |
| G.? cf. G.? lipperti | align="center" | | |
| rowspan="2" | Ancyrodella | A. rotundiloba alata | align="center" | |
| A. rotundiloba rotundiloba | align="center" | | |
| Icirodus | I. symmetricus | align="center" | |
| Roundya | A. aurita | align="center" | |
= Ammonoidea =
| class="wikitable sortable"
! Genus !! Species !! Notes | ||
| Timanites | T. angustus | align="center" | |
| Tornoceras | T. (T.) simplex | align="center" | |
= Arthropoda =
References
{{reflist}}
Category:Geologic formations of Australia
Category:Devonian System of Australia
Category:Devonian southern paleotropical deposits
Category:Devonian southern paleotemperate deposits
Category:Fossiliferous stratigraphic units of Oceania
Category:Paleontology in Australia