The Wallumbilla Formation is an
Aptian
The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...
geologic
formation
Formation may refer to:
Linguistics
* Back-formation, the process of creating a new lexeme by removing or affixes
* Word formation, the creation of a new word by adding affixes
Mathematics and science
* Cave formation or speleothem, a secondary ...
found in Australia.
Plesiosaur
The Plesiosauria or plesiosaurs are an Order (biology), order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia.
Plesiosaurs first appeared in the latest Triassic Period (geology), Period, possibly in the Rhaetian st ...
and
theropod
Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...
remains are among the
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
s that have been recovered from its strata.
Description
The formation is present in the Northern Territory, Queensland, South Australia, and New South Wales. It is a sedimentary unit, principally made up of mudstone and siltstone, with calcareous concretions. Its maximum thickness is 600 metres. Its age is somewhere from
Aptian
The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...
to
Albian
The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...
, that is between 125 and 101 Mya. The formation is part of the Wilgunya Subgroup, which in turn is part of the Rolling Downs Group of the
Eromanga and
Surat Basin
The Surat Basin is a geological basin in eastern Australia. It is part of the Great Artesian Basin drainage basin of Australia. The Surat Basin extends across an area of 270,000 square kilometres and the southern third of the basin occupies a larg ...
s. The named beds are the Coreena, Doncaster, Jones Valley, Ranmoor, and Trimble Members.
Geoscience Australia: Stratigraphic Units Database
/ref>
Fossil content
See also
* Plesiosaur stratigraphic distribution
* South Polar region of the Cretaceous
The South Polar region of the Cretaceous comprised the continent of East Gondwana–modern day Australia, Zealandia, and Antarctica–a product of the break-up of Gondwana in the Cretaceous Period. The southern region, during this time, was much w ...
References
{{Reflist
Further reading
* E. F. Riek. 1954. A second specimen of the dragon-fly ''Aeschnidiopsis flindersiensis'' (Woodward) from the Queensland Cretaceous. The Proceedings of the Linnean Society of New South Wales 79:61–62
Cretaceous System of Australia
Early Cretaceous Australia
Aptian Stage
Mudstone formations
Siltstone formations
Fossiliferous stratigraphic units of Oceania
Paleontology in Australia
Geology of New South Wales
Geology of the Northern Territory
Geology of Queensland
Geology of South Australia