Minchinbury Sandstone is a component of the
Wianammatta Group of
sedimentary
Sedimentary rocks are types of rock (geology), rock that are formed by the accumulation or deposition of mineral or organic matter, organic particles at Earth#Surface, Earth's surface, followed by cementation (geology), cementation. Sedimentati ...
rocks in the
Sydney Basin
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. ...
of eastern
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
.
Formation
Formed in the middle
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
period, this
sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates) ...
was structured by marine deposition as a set of sandy barrier islands at a coastal shoreline.
Location
The type locality of the formation is near the
Great Western Highway
Great Western Highway (also known as Broadway from to , Parramatta Road from Chippendale to , and Church Street through Parramatta) is a state highway in New South Wales, Australia. From east to west, the highway links Sydney with Bathurst, ...
in the suburb of
Minchinbury in western Sydney. It is most often seen in the western parts of the city. Outcroppings are weak and not easily found, but it may be seen in places like road cuttings in localities from
Epping Epping may refer to:
Places
Australia
* Epping, New South Wales, a suburb of Sydney
** Epping railway station, Sydney
* Electoral district of Epping, the corresponding seat in the New South Wales Legislative Assembly
* Epping Forest, Kearns, a he ...
,
Grose Vale-
Kurrajong,
Kellyville,
Rogans Hill,
Bankstown
Bankstown is a suburb south west of Sydney, in the state of New South Wales, Australia. It is 16 kilometres south-west of the Sydney central business district and is located in the local government area of the City of Canterbury-Bankstown, hav ...
,
Pendle Hill
Pendle Hill is in the east of Lancashire, England, near the towns of Burnley, Nelson, Colne, Brierfield, Clitheroe and Padiham. Its summit is above mean sea level. It gives its name to the Borough of Pendle. It is an isolated hill in the Pe ...
,
Bonnyrigg
Bonnyrigg ( sco, Bonnyrigg) is a town in Midlothian, Scotland, eight miles (13 kilometres) southeast of Edinburgh city centre. The town had a population of 14,663 in the 2001 census which rose to 15,677 in the 2011 census, both figures based ...
,
Menangle,
Duck River,
Brownlow Hill and other sites.
Description
Thickness is between 1.5 and 6 metres, usually less than 3 metres. It comprises up to 70% quartz with
calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
and volcanic
lithic fragments. There is less
feldspar
Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...
and more calcite than the adjacent
Bringelly Shale
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 geograp ...
. Related to
Greywacke
Greywacke or graywacke (German ''grauwacke'', signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or lit ...
, it comprises fine to medium-grained
lithic sandstone
Lithic sandstones, or lithic arenites, or litharenites, are sandstones with a significant (>5%) component of lithic fragments, though quartz and feldspar are usually present as well, along with some clayey matrix. Lithic sandstones can have a s ...
. The
Bringelly Shale
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 geograp ...
lies above the Minchinbury Sandstone.
Fossils are rare in this stratum, though plant fragments have been recorded.
See also
Sydney Basin
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. ...
,
Hawkesbury sandstone
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 ...
,
Bringelly Shale
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 geograp ...
,
Ashfield Shale
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 nam ...
,
Wianamatta shale
The Wianamatta Group is a geological feature of the Sydney Basin, New South Wales, Australia that directly overlies the older (but still Triassic in age) Hawkesbury sandstone and generally comprise fine grained sedimentary rocks such as shales an ...
,
Mittagong formation
The Mittagong Formation is a sedimentary rock unit in the Sydney Basin in eastern Australia.
Formation
Laid down in the Triassic Period, it may be seen as an interval of interbedded fine-grained sandstone and shale between the Ashfield Shale (ab ...
and
Narrabeen Group
The Narrabeen group of sedimentary rocks occurs in the Sydney Basin in eastern Australia. This series of rocks was formed in the Triassic Period.
Geology
It includes various rock types including lithic sandstone, quartz sandstone, siltstones, ...
.
References
Geology of New South Wales
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