The Wallumbilla Formation is an
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago) ...
geologic
formation found in Australia.
Plesiosaur
The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia.
Plesiosaurs first appeared ...
and
theropod
Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally ca ...
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 preserved in ...
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 in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago) ...
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 and Antarctica–a product of the break-up of Gondwana in the Cretaceous Period. The southern region, during this time, was much warmer than i ...
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
Geologic formations of Australia
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