St Michaels Cave | |
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Location | Avalon Beach, New South Wales, Australia |
Coordinates | 33°37′44.83″S151°20′21.23″E / 33.6291194°S 151.3392306°E |
Depth | 15 metres |
Length | 110 metres |
Geology | Dolerite & Narrabeen Group |
Hazards | falling rocks |
Access | not allowed |
Coordinates | 33°37′45″S151°20′21″E / 33.62912°S 151.33923°E Coordinates: 33°37′45″S151°20′21″E / 33.62912°S 151.33923°E |
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Managing authorities |
St Michaels Cave is situated in the Sydney suburb of Avalon Beach. This sea-side cave is around 110 metres long, 15 metres high and 10 metres wide. The original colonial owner was a Reverend John Therry, who planned to deliver lectures within the cave and build a church above it. The cave was formed by the erosion of a jurassic dyke through triassic sedimentary rocks. The cave is known to be a breeding site for Common bent-wing bats and Large-eared pied bats. [1] [2] [3] [4] [5] [6]
Sydney is the state capital of New South Wales and the most populous city in Australia and Oceania. Located on Australia's east coast, the metropolis surrounds Port Jackson and extends about 70 km (43.5 mi) on its periphery towards the Blue Mountains to the west, Hawkesbury to the north, the Royal National Park to the south and Macarthur to the south-west. Sydney is made up of 658 suburbs, 40 local government areas and 15 contiguous regions. Residents of the city are known as "Sydneysiders". As of June 2017, Sydney's estimated metropolitan population was 5,131,326, and is home to approximately 65% of the state's population.
The Jurassic was a geologic period and system that spanned 56 million years from the end of the Triassic Period 201.3 million years ago (Mya) to the beginning of the Cretaceous Period 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era, also known as the Age of Reptiles. The start of the period was marked by the major Triassic–Jurassic extinction event. Two other extinction events occurred during the period: the Pliensbachian-Toarcian extinction in the Early Jurassic, and the Tithonian event at the end; however, neither event ranks among the "Big Five" mass extinctions.
A dike or dyke, in geological usage, is a sheet of rock that is formed in a fracture in a pre-existing rock body. Dikes can be either magmatic or sedimentary in origin. Magmatic dikes form when magma flows into a crack then solidifies as a sheet intrusion, either cutting across layers of rock or through a contiguous mass of rock. Clastic dikes are formed when sediment fills a pre-existing crack.
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.
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.
The Garigal National Park is a protected national park that is located within the North Shore and Forest District regions of Sydney, New South Wales, in eastern Australia. The 2,202-hectare (5,440-acre) national park is situated approximately 20 kilometres (12 mi) north of the Sydney central business district.
The Northern Beaches is an area in the northern coastal suburbs of Sydney, in the state of New South Wales, Australia, near the Pacific coast. This area extends south to the entrance of Port Jackson, west to Middle Harbour and north to the entrance of Broken Bay. The area was formerly inhabited by the Garigal or Caregal people in a region known as Guringai country.
A ganister is hard, fine-grained quartzose sandstone, or orthoquartzite, used in the manufacture of silica brick typically used to line furnaces. Ganisters are cemented with secondary silica and typically have a characteristic splintery fracture.
Collaroy is a suburb in northern Sydney, in the state of New South Wales, Australia. Collaroy is 22 kilometres north-east of the Sydney central business district, in the local government area of Northern Beaches Council. It is part of the Northern Beaches region. Nicknamed "The Roy" by many of the locals.
Sydney Girls High School, is an academically selective public high school for girls located at Moore Park, in Sydney, NSW.
The Narrabeen group of sedimentary rocks occurs in the Sydney Basin in eastern Australia. This series of rocks was formed in the Triassic Period.
Bringelly Shale is a component of the Wianammatta 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.
Gregory John Retallack is an Australian paleontologist, geologist, and author who specializes in the study of fossil soils (paleopedology). His research has examined the fossil record of soils though major events in Earth history, extending back some 4.6 billion years. Among his publications he has written two standard paleopedology textbooks, said N. Jones in Nature Geoscience "Retallack has literally written the book on ancient soils."
The Australian Cyclists Party is a minor political party in Australia. It was registered with the New South Wales Electoral Commission in 2014, and unsuccessfully contested the 2015 New South Wales state election. It was also registered later with the Victorian Electoral Commission, and unsuccessfully contested the 2014 Victorian state election. It registered with the Australian Electoral Commission for federal elections on 20 August 2014 and voluntarily deregistered on 5 September 2017. It remained registered for New South Wales state elections, but not Victoria.
The Northern Beaches Council is a local government area located in the Northern Beaches region of Sydney, in the state of New South Wales, Australia. The Council was formed on 12 May 2016 after the amalgamation of Manly, Pittwater and Warringah Councils.
The Garie Formation is a narrow band of sedimentary rocks occurring in the Sydney Basin in eastern Australia. This stratum is up to 8 metres thick, situated below the sandstones of the Newport Formation. Formed in the mid-Triassic, it is part of the Narrabeen Group of sedimentary rocks. Garie formation consists of layers of clay pellet sandstone, dark lithic particles, spotted volcanic deposits and chocolate coloured claystone bands.
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. 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.
Long Reef is a prominent headland in the Northern Beaches of Sydney, Australia. Connected to the mainland by a tombolo, the reef has an extensive wave-cut platform. Long Reef is a popular recreational destination and is one of the more interesting geological areas in Sydney.
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