The Walloon Coal Measures are a

Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name ...

geologic subgroup in

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

. Deposited within the

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 lar ...

, it is considered Oxfordian to early

Tithonian In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by ...

in age based on lead-uranium dating of

tuffite Tuffite is a tuff containing both pyroclastic and detrital materials, but predominantly pyroclasts. According to IUGS definition tuffite contains 75 to 25% volcanic (epiclastic) material. There are several classifications that define tuffite. Th ...

s within the unit.

Description

The thick formation comprises thin-bedded,

claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone, slate, and shale. Most of the particles of which the stone is composed are less than and are too ...

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especiall ...

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, ...

s, lithic and sublithic to feldspathic

arenite Arenite ( Latin: ''arena'', "sand") is a sedimentary clastic rock with sand grain size between 0.0625 mm (0.00246 in) and 2 mm (0.08 in) and contain less than 15% matrix. The related adjective is ''arenaceous''. The equivalen ...

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when ...

seams and partings and minor

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms w ...

. The formation is laterally equivalent to the Mulgildie Coal Measures and Birkhead Formation.

Fossil content

The formation, in the Jurassic in the South Polar region, has provided fossil

flora Flora is all the plant life present in a particular region or time, generally the naturally occurring ( indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' gut flora'' or '' skin flora''. ...

and

trace fossil A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, ...

s of

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 c ...

ornithopod Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (), that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous w ...

s and '' Changpeipus bartholomaii'' and '' Garbina roeorum''. The dinosaur ''

Rhoetosaurus ''Rhoetosaurus'' (meaning "Rhoetos lizard"), named after Rhoetus, a titan in Greek Mythology, is a genus of sauropod dinosaur from the Jurassic ( Oxfordian) Walloon Coal Measures of what is now eastern Australia. ''Rhoetosaurus'' is estimated t ...

'' is known from the unit. 11 tracks are known from the formation, mostly those of large (prints 30-75 centimetres in length) theropods.

References

{{reflist

* L. C. Ball. 1933. Fossil footprints. Queensland Government Mining Journal 34(403):384 * A. Bartholomai. 1966. Fossil footprints in Queensland. Australian Natural History 15:147-150 * J. B. Cameron. 1970. The Rosewood-Walloon coalfield. Geological Survey of Queensland Publication 344:1-42 * Dudgeon, M.J., 1982, Stratigraphy and palaeobotany of east and west Haldon, Main Range, southeast Queensland., University of Queensland Department of Geology. Papers, 10(2), p83-110 * Green, P.M., Carmichael, D.C., Brain, T.J., Murray, C.G., McKellar, J.L., Beeston, J.W., Gray, A.R.G., 1997, Lithostratigraphic units in the Bowen and Surat Basins, Queensland IN: Green, P.M. (ed.) "The Surat and Bowen Basins, south-east Queensland", Queensland Minerals and Energy Review Series, Queensland Geological Survey, 1v, p41-108 * T. H. Rich and P. Vickers-Rich. 2003. A Century of Australian Dinosaurs. Queen Victoria Museum and Art Gallery and Monash Science Centre, Monash University 1-124 * J. F. Rigby. 1978. Jurassic plant fossils from the Walloon Coal Measures at Rosewood Consolidated Colliery. Queensland Government Mining Journal 526-529 * Wells, A.T., O'Brien, P.E., 1994, Lithostratigraphic framework of the Clarence-Moreton Basin IN Wells, A.T. and O'Brien, P.E. (eds.) "Geology and Petroleum Potential of the Clarence-Moreton Basin, New South Wales and Queensland", Australian Geological Survey Organisation. Bulletin, 241, p4-47 Geologic formations of Australia Jurassic System of Australia Oxfordian Stage Kimmeridgian Stage Tithonian Stage Shale formations Siltstone formations Sandstone formations Coal formations Coal in Australia Ichnofossiliferous formations Paleontology in Queensland

Description

Fossil content

References

Further reading