Bringelly Shale | |
---|---|
Stratigraphic range: Middle Triassic | |
Type | Geological formation |
Unit of | Wiannamatta group |
Overlies | Hawkesbury sandstone |
Thickness | up to 60 metres (200 ft) |
Location | |
Location | Western Sydney |
Region | Cumberland Plain |
Country | Australia |
Type section | |
Named for | Bringelly |
Bringelly Shale is a component of the Wianamatta group of sedimentary rocks in the Sydney Basin of eastern Australia. Formed in the Triassic Period, it has an extensive outcrop in the western parts of Sydney. The shale has its greatest geographical extent at Bringelly, near the suburb of Liverpool.
The shale is the topmost layer of sedimentary rock laid down by a river delta over the older Hawkesbury sandstone in the Triassic Period. [1]
It is similar to Ashfield Shale in that both have low porosities, though differing in having a greater amount of calcareous, graywacke-type, lithic sandstone bands and lenses, carbonaceous claystone, siltstone, laminite, but would lack sideritic mudstone bands that Ashfield Shale has. Bringelly Shale has lumpy clay minerals, and it swells and decays rapidly on submergence in water and is generally less durable. [2]
The average thickness is around 60 metres. [3] It was deposited in a swampy alluvial plain with winding streams that formed sporadic beds of sandstone. The shale is dark when unweathered just like the Ashfield Shale. The shale is usually a typical olive-green colour when weathered. Alloyed coal bands and lenses and iron oxide concretions have been observed in the shale. The shale is quarried in many western suburbs of Sydney for brick and miscellaneous ceramic manufacture. [4]
Ku-ring-gai Chase National Park is a national park on the northern side of Sydney in New South Wales, Australia. The 14,977-hectare (37,010-acre) park is 25 kilometres (16 mi) north of the Sydney central business district and generally comprises the land east of the M1 Pacific Motorway, south of the Hawkesbury River, west of Pittwater and north of Mona Vale Road. It includes Barrenjoey Headland on the eastern side of Pittwater.
The Wollemi National Park is a protected national park and wilderness area that is located in the Central West and Hunter region of New South Wales, in eastern Australia. The 501,703-hectare (1,239,740-acre) park, the second largest national park in New South Wales, contains the 361,113-hectare (892,330-acre) Wollemi Wilderness – the largest such wilderness area in Australia – and is situated approximately 130 kilometres (81 mi) northwest of Sydney.
The South Creek or Wianamatta is a creek that is part of the Hawkesbury-Nepean catchment, located on the Cumberland Plain in Greater Western Sydney, New South Wales, Australia.
The Sydney Basin is an interim Australian bioregion and is both a structural entity and a depositional area, now preserved on the east coast of New South Wales, Australia and with some of its eastern side now subsided beneath the Tasman Sea. The basin is named for the city of Sydney, on which it is centred.
The geography of Sydney is characterised by its coastal location on a basin bordered by the Pacific Ocean to the east, the Blue Mountains to the west, the Hawkesbury River to the north and the Woronora Plateau to the south. Sydney lies on a submergent coastline on the east coast of New South Wales, where the ocean level has risen to flood deep river valleys (rias) carved in the Sydney sandstone. Port Jackson, better known as Sydney Harbour, is one such ria.
Sydney sandstone, also known as the Hawkesbury sandstone, yellowblock, and yellow gold, is a sedimentary rock named after Sydney, and the Hawkesbury River north of Sydney, where this sandstone is particularly common.
The Cumberland Plain, also known as Cumberland Basin, is a relatively flat region lying to the west of Sydney CBD in New South Wales, Australia. An IBRA biogeographic region, Cumberland Basin is the preferred physiographic and geological term for the low-lying plain of the Permian-Triassic Sydney Basin found between Sydney and the Blue Mountains, and it is a structural sub-basin of the Sydney Basin.
The Wianamatta Group is a geological feature of the Sydney Basin, New South Wales, Australia that directly overlies the older Hawkesbury sandstone and generally comprise fine grained sedimentary rocks such as shales and laminites as well as less common sandstone units.
The Central Tablelands in New South Wales is a geographic area that lies between the Sydney Metropolitan Area and the Central Western Slopes and Plains. The Great Dividing Range passes in a north–south direction through the Central Tablelands and includes the Blue Mountains. The region shares borders with the Hunter, Central West Slopes and Plains, South West Slopes, Southern Tablelands, North Western Slopes and Plains, the Sydney Metropolitan Area and the Illawarra.
The Narrabeen group of sedimentary rocks occurs in the Sydney Basin in eastern Australia. This series of rocks was formed in the Triassic Period.
The Mittagong Formation is a sedimentary rock unit in the Sydney Basin in eastern Australia.
Geologically the Australian state of New South Wales consists of seven main regions: Lachlan Fold Belt, the Hunter-Bowen Orogeny or New England Orogen (NEO), the Delamerian Orogeny, the Clarence Moreton Basin, the Great Artesian Basin, the Sydney Basin, and the Murray Basin.
The Clarence Moreton Basin is a Mesozoic sedimentary basin on the easternmost part of the Australian continent. It is located in the far north east of the state of New South Wales around Lismore and Grafton and in the south east corner of Queensland. It is the part of the Great Artesian Basin that extends to the east coast in Australia's central eastern lowlands.
Ashfield Shale is part of the Wianamatta group of sedimentary rocks in the Sydney Basin. It lies directly on contemporaneously eroded Hawkesbury sandstone or the Mittagong formation. These rock types were formed in the Triassic Period. It is named after the Sydney suburb of Ashfield. Some of the early research was performed at the old Ashfield Brickworks Quarry. This rock type is often associated with the Inner West and North Shore of the city. However, it has also been recorded at Penrith, Revesby, Bilpin and Mount Irvine.
The Illawarra Coal Measures is a group of sedimentary rocks occurring in the Sydney Basin in eastern Australia. This stratum is up to 150 metres thick. Formed in the Late Permian, it comprises shale, quartz-lithic sandstone, conglomerate rocks, and chert, with sporadically carbonaceous mudstone, coal and seams of torbanite. Coal mining of these measures remains a significant commercial enterprise to the present day. One of the abandoned coal mines in the Blue Mountains is now a tourist attraction.
Minchinbury Sandstone is a component of the Wianammatta Group of sedimentary rocks in the Sydney Basin of eastern Australia.
The Hornsby Plateau is a dissected sandstone plateau lying to the north of Sydney Harbour that rises 200 metres. The plateau is a part of the larger Sydney Basin structure.
Bald Hill Claystone is a sedimentary rock found in the Sydney Basin in eastern Australia. It is part of the Clifton sub-group of the Narrabeen Group of sedimentary rocks. It was formed by weathering of the Gerringong Volcanics in the early Triassic. Named after Bald Hill, in the northern Illawarra, where it is 15 metres thick. The claystone is easily noticed at Long Reef, where it is 18 metres thick.
Bulgo Sandstone is a sedimentary rock occurring in the Sydney Basin in eastern Australia. This stratum is up to 100 metres thick, formed in the early Triassic (Olenekian). A component of the Narrabeen Group of sedimentary rocks. It consists of layers of fine to medium-grained quartz-lithic sandstone, with lenticular shale interbeds.
The Prospect dolerite intrusion, or Prospect intrusion, is a Jurassic picrite or dolerite laccolith that is situated in Sydney, New South Wales, Australia. Lying in the heart of Cumberland Plain, in the suburb of Pemulwuy, the intrusion is Sydney's largest body of igneous rock, rising to a height of 117 metres (384 ft) above sea level. The site is formed by an intrusion of dolerite rock into Ashfield Shale. At least seven different rock types occur in the intrusion.