Wianamatta Shale is a geological feature of the Sydney Basin, New South Wales, Australia. The Wianamatta Group directly overlies the older (but still Triassic in age) Hawkesbury sandstone. The shales generally comprises fine grained sedimentary rocks such as shales and laminites with less common sandstone units.
The Wianamatta Group is made up of the following units (listed in stratigraphic order):
The Wianamatta Group is the youngest geological layer member of the Sydney Basin, and therefore lies at the highest point as the highest layer member. It was deposited in connection with a large river delta, which shifted over time from west to east. This is evidenced by the sequence of strata, which clearly show the transition from marine deposits in front of the delta to deposits on land: Ashfield shale was formed from clayey marine sediments. The subsequent Minchinbury Sandstone emerged from beach - Nehrungs Islands. The Bringelly shale became alluvial in a marshy plain deposited on the delta, meandered through the rivers, and deposited sand at various locations, each of which was narrowly defined, which later solidified into sandstone. [1]
Today's weathering of the surface of the existing claystone produces abundant clay, which leads to the formation of clay soils with low water permeability, as they occur, for example, on the Cumberland Plain widespread. Here are Podsol floors widespread that swell when supplying water and shrink during drying.
Over the pitches of the Wianamatta Group, water-bearing layers can form. Deep and large clay deposits of this formation are able to collect groundwater; however, if they are at or near the surface, salted dry land may form as the water evaporates. The quality of the groundwater over the pitches can be good, so that drinkable water occurs, or it can be very saline and thus not potable. The lower groundwater resources in the Wianamatta Group rocks are generally less saline than the near-surface occurrences. [2]
Wianamatta is spelled according to the way it sounded when spoken by the original Aboriginal people when questioned by the Rev. William Branwhite Clarke. Any reference to any other spelling sourced in the "trove" article in the Sydney Morning Herald is a typographical error.
The Wianamatta Group has been inferred to represent a cycle of basin infilling associated with the migration of a large delta front from west to east. The Ashfield Shale was deposited in a low energy marine environment and preserves laminated silty sediments. The Minchinbury Sandstone comprises a set of sandy barrier islands at the former shoreline. The Bringelly Shale was deposited in a swampy alluvial plain with meandering streams flowing from the west forming discontinuous beds of sandstone. [3]
Weathering of the shale units produces a rich clayey soil, often with poor drainage, such as that in the Cumberland Plain. [4] These clay soils are recognised as being reactive with appreciable Shrink-swell capacity.
Low-lying areas where groundwater is close to the surface are also susceptible to dryland salinity. Groundwater quality can range from fresh to highly saline, with the deeper groundwater generally less saline.
Other rock types found in the Sydney Basin include the Narrabeen shale, Mittagong formation, Illawarra Coal Measures, Newcastle Coal Measures, and Shoalhaven Group.
Shale is a fine-grained, clastic sedimentary rock, composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. Shale is characterized by breaks along thin laminae or parallel layering or bedding less than one centimeter in thickness, called fissility. It is the most common sedimentary rock.
The Wollemi National Park is a protected national park and wilderness area that is located in the northern Blue Mountains and Lower Hunter regions 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 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.
Bents Basin is a protected nature reserve and state park near Wallacia, New South Wales, Australia in the Sydney metropolitan area. The lake basin, which formed at the efflux of the Nepean River from the Hawkesbury Sandstone gorge, is a popular swimming hole with a camping area and an education centre used by local school groups. Also featuring a large woodland area and native wildlife, the reserve is the only picnic area along the Nepean River and it is one of the most popular water-based picnic parks in Greater Western Sydney.
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 is the common name for Sydney Basin Hawkesbury Sandstone, one variety of which is historically known as Yellowblock, and also as "yellow gold" a sedimentary rock named after the Hawkesbury River north of Sydney, where this sandstone is particularly common.
The Cumberland Plain, an IBRA biogeographic region, is a relatively flat region lying to the west of Sydney CBD in New South Wales, Australia. 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 Narrabeen group of sedimentary rocks occurs in the Sydney Basin in eastern Australia. This series of rocks was formed in the Triassic Period.
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 Queenston Formation is a geological formation of Upper Ordovician age, which outcrops in Ontario, Canada and New York, United States. A typical outcrop of the formation is exposed at Bronte Creek just south of the Queen Elizabeth Way. The formation is a part of the Queenston Delta clastic wedge, formed as an erosional response to the Taconic Orogeny. Lithologically, the formation is dominated by red and grey shales with thin siltstone, limestone and sandstone interlayers. As materials, comprising the clastic wedge, become coarser in close proximity to the Taconic source rocks, siltstone and sandstone layers are predominant in New York.
Ashfield Shale is part of the Wiannamatta 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.
Bringelly Shale is a component of the Wianamatta group of sedimentary rocks in the Sydney Basin of eastern Australia. It was formed in the Triassic Period. It is most often seen in the western parts of the city. The shale has its greatest geographical extent at Bringelly, near the suburb of Liverpool. It is similar to Ashfield Shale, though differing in having a greater amount of sandstone and lacking sideritic mudstone bands. The average thickness is around 60 metres. The Bringelly Shale was deposited in a swampy alluvial plain with meandering streams flowing from the west forming discontinuous beds of sandstone.
Minchinbury Sandstone is a component of the Wianammatta Group of sedimentary rocks in the Sydney Basin of eastern Australia.
The Cumberland Plain Woodland is one of six main indigenous woodland communities of Sydney, New South Wales, Australia, that comprises an open tree canopy, a groundcover with grasses and herbs, usually with layers of shrubs and/or small trees. Situated in the Cumberland Plain, it is made up of dry sclerophyll woodlands, grasslands and/or forests, reminiscent of Mediterranean forests and temperate grasslands. Currently, less than 6% of the Woodlands remain in small parts distributed across the western suburbs of Sydney, totaling only around 6400 hectares.
The geology of Gambia is defined by thick and comparatively recent sequences of sediments and sedimentary rocks, deposited in the last 66 million years. The country is underlain almost entirely by geologically recent Cenozoic sedimentary rocks. Much deeper basement rocks are likely present, although they are not well understood. Most research has focused on oil and groundwater exploration.
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The geology of Nigeria formed beginning in the Archean and Proterozoic eons of the Precambrian. The country forms the Nigerian Province and more than half of its surface is igneous and metamorphic crystalline basement rock from the Precambrian. Between 2.9 billion and 500 million years ago, Nigeria was affected by three major orogeny mountain-building events and related igneous intrusions. Following the Pan-African orogeny, in the Cambrian at the time that multi-cellular life proliferated, Nigeria began to experience regional sedimentation and witnessed new igneous intrusions. By the Cretaceous period of the late Mesozoic, massive sedimentation was underway in different basins, due to a large marine transgression. By the Eocene, in the Cenozoic, the region returned to terrestrial conditions.
The geology of Mississippi includes some deep igneous and metamorphic crystalline basement rocks from the Precambrian known only from boreholes in the north, as well as sedimentary sequences from the Paleozoic. The region long experienced shallow marine conditions during the tectonic evolutions of the Mesozoic and Cenozoic, as coastal plain sediments accumulated up to 45,000 feet thick, including limestone, dolomite, marl, anhydrite and sandstone layers, with some oil and gas occurrences and the remnants of Cretaceous volcanic activity in some locations.
The geology of North Dakota includes thick sequences oil and coal bearing sedimentary rocks formed in shallow seas in the Paleozoic and Mesozoic, as well as terrestrial deposits from the Cenozoic on top of ancient Precambrian crystalline basement rocks. The state has extensive oil and gas, sand and gravel, coal, groundwater and other natural resources.
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