The Precipice Sandstone an Early Jurassic (

Sinemurian In the geologic timescale, the Sinemurian is an age (geology), age and stage (stratigraphy), stage in the Early Jurassic, Early or Lower Jurassic epoch (geology), Epoch or series (stratigraphy), Series. It spans the time between 199.5 ±0.3 annu ...

to early

Pliensbachian The Pliensbachian is an age of the geologic timescale and stage in the stratigraphic column. It is part of the Early or Lower Jurassic Epoch or Series and spans the time between 192.9 ±0.3 Ma and 184.2 ±0.3 Ma (million years ago). The Plie ...

, with possible Hettangian levels) 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 ...

of 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 larg ...

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

and

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

, eastern Australia, know due to the presence of abundant vertebrate remains & tracks. This unit includes the previously described Razorback beds. This unit represents a major, almost primary, source of hydrocarbons in the region, with a Potential CO2 reservoir of up to 70m. It was deposited on top of older sediments, like

Bowen Basin The Bowen Basin contains the largest coal reserves in Australia. This major coal-producing region contains one of the world's largest deposits of bituminous coal. The Basin contains much of the known Permian coal resources in Queensland includ ...

units, in an unconformable manner, resting along the eastern basin margin and the Back Creek Group in the southern

Comet Platform A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or coma surrounding the nucleus, and ...

, while in other areas it directly overlies the Triassic Moolayember Formation &

Callide Coal Measures Callide may refer to: * Callide, Queensland, a locality in the Shire of Banana, Queensland, Australia * Electoral district of Callide Callide is an electoral division in Queensland, Australia. It encompasses agricultural and mining towns in ...

, being deposited in a comparatively stable basin. Isopach maps of the Precipice Sandstone indicate two distinct areas of sediment accumulation, suggesting two separate depocentres filled from different source regions during the Sinemurian, with the

Thomson orogeny The Thomson Orogeny was a mountain building event (orogeny) from 510 to 495 million years in Gondwana, now situated mainly in the Australian state of Queensland. Structural geology and sequence of events The rocks deformed during the Thomson Orog ...

and

New England Orogen New or NEW may refer to: Music * New, singer of K-pop group The Boyz * ''New'' (album), by Paul McCartney, 2013 ** "New" (Paul McCartney song), 2013 * ''New'' (EP), by Regurgitator, 1995 * "New" (Daya song), 2017 * "New" (No Doubt song), 19 ...

hinterlands as possible ones. This unit represented a fluvial-palustrine-lacustrine braided channel north-flowing succession, that seem to have debouch into a shallow restricted tidal/wave influenced marine embayment, marked at areas like Woleebee Creek. Paleoenvironment-wise, it represents a hinterland rich in vegetation, hinting at wet environments like swamps, where agglutinated foraminifera suggests marine flooding and drier conditions or the encroachment of seawater onto coastal areas.

Fireclay Caverns

The Fireclay Caverns were excavated by the

Mount Morgan Mine Mount Morgan Mine was a copper, gold and silver mine in Queensland, Australia. Mining began at Mount Morgan, Queensland, Mount Morgan in 1882 and continued until 1981. Over its lifespan, the mine yielded approximately of gold, of silver and ...

to provide clay for its brickworks resulting in very large openings that measure between 4–12 metres in height from the cave floor. Excavation of the caverns ceased when the mine brickworks were decommissioned in the early 1900s. Erosion revealed

dinosaur footprints A fossil track or ichnite (Greek "''ιχνιον''" (''ichnion'') – a track, trace or footstep) is a fossilized footprint. This is a type of trace fossil. A fossil trackway is a sequence of fossil tracks left by a single organism. Over the year ...

(preserved as infills) being discovered in 1954. To date, nine different ceiling sections of the Fireclay Caverns have been recognised as containing

. These have been dated to the

Early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic� ...

(

) ~195 million years ago. Walkways and stairs had been constructed in 2010 to provide access to the dinosaur footprints as part of the mine site tours. The site was closed to access in 2011 due to ceiling erosion posing a significant risk to public safety. The Fireclay Caverns were excavated to supply clay to brickworks of the

. Clay was mined from within the caverns by pick and shovel, then transferred by underground rail to a brickworks lower in the

site. Excavation from the caverns ceased when their clay was no longer required by the mine. After cavern excavations ceased, clay progressively fell from the cavern ceilings, revealing rock ceilings above. In 1954, HRE Staines, a Mount Morgan Limited geologist, identified dinosaur footprints in the rock ceilings. Over 300 such footprints have been identified on the cavern ceilings dated to the

(

) ~195 million years ago. 2024 represents the 70th anniversary of when Ross Staines published Australia's first dinosaur trackway-consisting of four footprints. To celebrate, previously unpublished archival photographs (c. 1954) enabled a re-examination of Staines' original trackway, from which two additional footprints were revealed. Analyses indicated the trackmaker exhibited a walking gait, initially walking at ~3.8 km/h and then slowed to 1.8 km/h in association with a slight turn in direction. After cavern excavations ceased, a colony of bent-wing bats began inhabiting the caverns. The sections of the caverns containing the bats are inaccessible to protect the bat habitat.

Biota

Invertebrates

Vertebrata

Bryophyta

Lycophyta

Pteridophyta

Peltaspermales

Conifers

References

{{Reflist Jurassic System of Australia Sinemurian Stage Pliensbachian Stage Sandstone formations Paleontology in New South Wales Paleontology in Queensland Caves of Queensland Central Queensland

Fireclay Caverns

Biota

Invertebrates

Vertebrata

Bryophyta

Lycophyta

Pteridophyta

Pteridophyta

Peltaspermales

Conifers

See also

References