83-538: Download coordinates as: Mount Coot-tha is a mountain and a suburb of the City of Brisbane , Queensland , Australia. Visible from much of the city, Mount Coot-tha is a popular bushland tourist destination including the Mount Coot-tha Lookout , Brisbane Botanic Gardens and Sir Thomas Brisbane Planetarium , as well as a mountain drive, bike trails, parks including a waterfall, and television and radio towers. In
166-579: A Pacific Island zone. The major exhibit is the 27-hectare (67-acre) display of native Australian plants (with emphasis on Queensland plants), featuring an artificial lagoon. Mount Coot-tha has a public library on Mt Coot-tha Road in the Brisbane Botanic Gardens operated by the Brisbane City Council . Unlike most public libraries in Brisbane which have general collections, this library holds
249-456: A border with Brisbane Forest Park , which adds a further 25,000 hectares. On a ridge near the summit on the other side of Mount Coot-tha, are the television transmission towers for the Brisbane television stations and their respective studios; Ten ( TVQ-10 ), Nine ( QTQ-9 ), Seven ( BTQ-7 ). The transmission tower for ( ABC Brisbane ) is located on the mountain, which also broadcasts television for multicultural station SBS and previously
332-408: A distinctive composition or mode or origin. Special names still in wide use include amphibolite, greenschist , phyllite, marble, serpentinite , eclogite, migmatite , skarn , granulite , mylonite, and slate. The basic classification can be supplemented by terms describing mineral content or texture. For example, a metabasalt showing weak schistosity might be described as a gneissic metabasalt, and
415-451: A distinctive layering called foliation (derived from the Latin word folia , meaning "leaves"). Foliation develops when a rock is being shortened along one axis during recrystallization. This causes crystals of platy minerals, such as mica and chlorite , to become rotated such that their short axes are parallel to the direction of shortening. This results in a banded, or foliated, rock, with
498-578: A grading under the International Mountain Bicycling Association , Trail Difficulty Rating System. The multi-use trails in Mount Coot-tha provide the least degree of technical challenge to mountain bike riders, however many of them are steep and loose. Riders are advised to pay special attention when riding over the erosion control banks (water bars) which have been the downfall of many a novice rider. The trail ratings provide
581-442: A guide to the relative difficulty of each trail. The multi-use tracks are used by horses, pedestrians and mountain bikers. Each year orienteering events are held in the area. Mount Coot-tha can be reached by Brisbane Transport Bus 471 ( Translink ). Between 2014 and 2016 the Brisbane City Council ran a CitySights Bus that included Mount Coot-tha. A short taxi ride from Toowong is also possible as well as Uber and such. Parking
664-629: A large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by their protolith, their chemical and mineral makeup, and their texture . They may be formed simply by being deeply buried beneath the Earth's surface, where they are subject to high temperatures and the great pressure of the rock layers above. They can also form from tectonic processes such as continental collisions, which cause horizontal pressure, friction, and distortion. Metamorphic rock can be formed locally when rock
747-464: A marble will not be identical with the amphibolite facies of a pelite. However, the facies are defined such that metamorphic rock with as broad a range of compositions as is practical can be assigned to a particular facies. The present definition of metamorphic facies is largely based on the work of the Finnish geologist, Pentti Eskola , with refinements based on subsequent experimental work. Eskola drew upon
830-522: A metamorphic rock to be classified in this manner, the protolith should be identifiable from the characteristics of the metamorphic rock itself, and not inferred from other information. Under the British Geological Survey's classification system, if all that can be determined about the protolith is its general type, such as sedimentary or volcanic, the classification is based on the mineral mode (the volume percentages of different minerals in
913-413: A pelite containing abundant staurolite might be described as a staurolite pelite. [REDACTED] A metamorphic facies is a set of distinctive assemblages of minerals that are found in metamorphic rock that formed under a specific combination of pressure and temperature. The particular assemblage is somewhat dependent on the composition of that protolith, so that (for example) the amphibolite facies of
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#1733085161764996-538: A population of 0 people. In the 2021 census , Mount Coot-tha had a population of 0 people. Mount Coot-tha has a number of heritage-listed sites, including: Mount Coot-tha is one of Brisbane's most popular tourist destinations and is a popular stop with bus tours. Of particular note is the Lookout, which includes the Kuta Cafe, Summit Restaurant, and Gift Shop. The lookout, restaurant and cafe allow for panoramic views of
1079-710: A process to formally define their boundaries and to gazette them, which is almost complete. In March 2006, only South Australia and the Northern Territory had not completed this process. The CGNA's Gazetteer of Australia recognises two types of locality: bounded and unbounded. Bounded localities include towns, villages, populated places, local government towns and unpopulated town sites, while unbounded localities include place names, road corners and bends, corners, meteorological stations, ocean place names and surfing spots. Sometimes, both localities and suburbs are referred to collectively as "address localities". In
1162-519: A relatively mild grade of metamorphism, at temperatures of 350–500 °C (662–932 °F) and pressures of 200–500 MPa (2,000–5,000 bar). They can be divided into a lower group of metabasalts, including rare meta komatiites ; a middle group of meta-intermediate-rock and meta-felsic-rock; and an upper group of metasedimentary rock. The greenstone belts are surrounded by high-grade gneiss terrains showing highly deformed low-pressure, high-temperature (over 500 °C (932 °F)) metamorphism to
1245-548: A specialist collection about botany and astronomy and related topics reflecting its locations within the botanic garden and the Brisbane Planetarium also on the site. There are several popular walking tracks around Mount Coot-tha, one of which includes an art display comprising works produced by local Aboriginal artists. The tracks vary in difficulty, with most involving some uphill sections or steps. Tracks around Mount Coot-tha are often used by hikers training to walk
1328-410: A variety of metamorphic facies. Where subduction is taking place, the basalt of the subducting slab is metamorphosed to high-pressure metamorphic facies. It initially undergoes low-grade metamorphism to metabasalt of the zeolite and prehnite-pumpellyite facies , but as the basalt subducts to greater depths, it is metamorphosed to the blueschist facies and then the eclogite facies . Metamorphism to
1411-417: Is a great variety of metamorphic rock types. In general, if the protolith of a metamorphic rock can be determined, the rock is described by adding the prefix meta- to the protolith rock name. For example, if the protolith is known to be basalt , the rock will be described as a metabasalt. Likewise, a metamorphic rock whose protolith is known to be a conglomerate will be described as a metaconglomerate . For
1494-495: Is a loop road around the mountain, passing by (clockwise) Mount Coot-tha, Constitution Hill, and The Summit. It provides access to the Mount Coot-tha Lookout with its cafe and restaurant, the radio and television stations with their transmission towers at The Summit (originally located there to maximise transmission), picnic areas, and walking and cycling tracks. One of the walking tracks provides access to The Pinnacle. It
1577-502: Is a more accurate transcription, and that Coot-tha is a separate word translating to an obscenity; supposedly a joke played on Radford by Kerwalli. In the mid 1890s, the Shire of Toowong (then the local government for the area) established a quarry on the side of the mountain. Following the 1925 amalgamation of local government areas that created the City of Brisbane, the ownership and operation of
1660-530: Is also prized for building construction and as a medium for sculpture. On the other hand, schist bedrock can pose a challenge for civil engineering because of its pronounced planes of weakness. Metamorphic rocks form one of the three great divisions of rock types. They are distinguished from igneous rocks , which form from molten magma , and sedimentary rocks , which form from sediments eroded from existing rock or precipitated chemically from bodies of water. Metamorphic rocks are formed when existing rock
1743-426: Is called a paired metamorphic belt . The main islands of Japan show three distinct paired metamorphic belts, corresponding to different episodes of subduction. Metamorphic rock is also exposed in metamorphic core complexes , which form in region of crustal extension. They are characterized by low-angle faulting that exposes domes of middle or lower crust metamorphic rock. These were first recognized and studied in
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#17330851617641826-464: Is dominated by metamorphic rock that has reached the amphibolite facies. Within the upper crust, which is the only part of the Earth's crust geologists can directly sample, metamorphic rock forms only from processes that can occur at shallow depth. These are contact (thermal) metamorphism , dynamic (cataclastic) metamorphism , hydrothermal metamorphism , and impact metamorphism . These processes are relatively local in occurrence and usually reach only
1909-476: Is formed as tectonic plates move apart. Hydrothermal metamorphism is extensive here. This is characterized by metasomatism by hot fluids circulating through the rock. This produces metamorphic rock of the greenschist facies. The metamorphic rock, serpentinite , is particularly characteristic of these settings, and represents chemical transformation of olivine and pyroxene in ultramafic rock to serpentine group minerals. Contact metamorphism takes place when magma
1992-464: Is heated by the intrusion of hot molten rock called magma from the Earth's interior. The study of metamorphic rocks (now exposed at the Earth's surface following erosion and uplift) provides information about the temperatures and pressures that occur at great depths within the Earth's crust. Some examples of metamorphic rocks are gneiss , slate , marble , schist , and quartzite . Slate and quartzite tiles are used in building construction. Marble
2075-403: Is injected into the surrounding solid rock ( country rock ). The changes that occur are greatest wherever the magma comes into contact with the rock because the temperatures are highest at this boundary and decrease with distance from it. Around the igneous rock that forms from the cooling magma is a metamorphosed zone called a contact aureole . Aureoles may show all degrees of metamorphism from
2158-405: Is known as burial metamorphism . This tends to produce low-grade metamorphic rock. Much more common is metamorphic rock formed during the collision process itself. The collision of plates causes high temperatures, pressures and deformation in the rocks along these belts. Metamorphic rock formed in these settings tends to shown well-developed schistosity. Metamorphic rock of orogenic belts shows
2241-474: Is limited at the lookout. The Mount Coot-tha Quarry is the subject of ongoing complaints by nearby residents claiming that it is a "massive scar on the landscape" and that they have been adversely affected by dust, noise, vibration, and damage arising from the blasting, claiming that blasts last up to 30 seconds. The Brisbane City Council counters the complaints by pointing out that the quarry has been in place for so long that any residents should have been aware of
2324-439: Is often claimed that Mount Coot-tha is the "highest point in Brisbane", but, as the elevations above show, the peak known as Mount Coot-tha is not even the highest peak of the mountain as a whole with both Constitution Hill and The Summit being higher. However, Mount Coot-tha has a lookout with unobscured views over much of Brisbane, while Constitution Hill and The Summit do not. Further to the west, there are even higher peaks within
2407-442: Is split between the City of Newcastle and City of Lake Macquarie LGAs; and Woodville , which is split between the City of Maitland and Port Stephens Council LGAs. In unincorporated areas , localities are declared by the relevant state authority. Metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism . The original rock ( protolith )
2490-451: Is subjected to temperatures greater than 150 to 200 °C (300 to 400 °F) and, often, elevated pressure of 100 megapascals (1,000 bar ) or more, causing profound physical or chemical changes. During this process, the rock remains mostly in the solid state, but gradually recrystallizes to a new texture or mineral composition. The protolith may be an igneous , sedimentary , or existing metamorphic rock. Metamorphic rocks make up
2573-506: Is sufficiently hard and dense that it is difficult to quarry. However, some quartzite is used as dimension stone , often as slabs for flooring, walls, or stairsteps. About 6% of crushed stone, used mostly for road aggregate, is quartzite. Marble is also prized for building construction and as a medium for sculpture. Schistose bedrock can pose a challenge for civil engineering because of its pronounced planes of weakness. A hazard may exist even in undisturbed terrain. On August 17, 1959,
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2656-545: Is transformed physically or chemically at elevated temperature, without actually melting to any great degree. The importance of heating in the formation of metamorphic rock was first noted by the pioneering Scottish naturalist, James Hutton , who is often described as the father of modern geology. Hutton wrote in 1795 that some rock beds of the Scottish Highlands had originally been sedimentary rock but had been transformed by great heat. Hutton also speculated that pressure
2739-400: Is uncertain. Special classifications exist for metamorphic rocks with a volcaniclastic protolith or formed along a fault or through hydrothermal circulation . A few special names are used for rocks of unknown protolith but known modal composition, such as marble, eclogite , or amphibolite . Special names may also be applied more generally to rocks dominated by a single mineral, or with
2822-400: Is used in rural areas, while the term suburb is used in urban areas. Australian postcodes closely align with the boundaries of localities and suburbs. This Australian usage of the term "suburb" differs from common American and British usage, where it typically means a smaller, frequently separate residential community outside, but close to, a larger city. The Australian usage is closer to
2905-426: Is used only when very little else is known about the rock that would allow a more definite classification. Textural classifications may be prefixed to indicate a sedimentary protolith ( para- , such as paraschist) or igneous protolith ( ortho- , such as orthogneiss). When nothing is known about the protolith, the textural name is used without a prefix. For example, a schist is a rock with schistose texture whose protolith
2988-475: Is usually devoid of schistosity and forms a tough, equigranular rock. If the rock was originally banded or foliated (as, for example, a laminated sandstone or a foliated calc- schist ) this character may not be obliterated, and a banded hornfels is the product. Contact metamorphism close to the surface produces distinctive low-pressure metamorphic minerals, such as spinel , andalusite, vesuvianite , or wollastonite . Similar changes may be induced in shales by
3071-470: Is very low in silica) to metafelsic-rock (with a high silica content). Where the mineral mode cannot be determined, as is often the case when rock is first examined in the field , then classification must be based on texture. The textural types are: A hornfels is a granofels that is known to result from contact metamorphism. A slate is a fine-grained metamorphic rock that easily splits into thin plates but shows no obvious compositional layering. The term
3154-513: The 2021 census , Mount Coot-tha had a population of 0 people. The mountain Mount Coot-tha forms the eastern extent of the Taylor Range and is a prominent landmark approximately six kilometres (4 mi) to the west of the Brisbane central business district . Mount Coot-tha is the source of Ithaca Creek . The mountain has a number of named peaks in the suburb: Sir Samuel Griffith Scenic Drive
3237-566: The Basin and Range Province of southwestern North America, but are also found in southern Aegean Sea , in the D'Entrecasteaux Islands , and in other areas of extension. Continental shields are regions of exposed ancient rock that make up the stable cores of continents. The rock exposed in the oldest regions of shields, which is of Archean age (over 2500 million years old), mostly belong to granite-greenstone belts. The greenstone belts contain metavolcanic and metasedimentary rock that has undergone
3320-643: The Kokoda Track in Papua New Guinea as the terrain and climate are considered similar. The Western side of Mount Coot-tha Forest or Gap Creek Reserve as it is known to the locals is a haven for Brisbane mountain bike riders. The establishment of a world class mountain bike trail network by the Brisbane City Council has created a diverse range of recreational experiences for off-road cyclists. The mountain bike trails at Mount Coot-tha have been assigned
3403-477: The Kokoda Track in Papua New Guinea during World War II . In 2017, it was proposed to build Australia's longest flying fox from the summit of Mount Coot-tha down to the Brisbane Botanic Gardens . Despite initially being approved by the Brisbane City Council , in April 2019 the new Mayor of Brisbane Adrian Schrinner decided to cancel the project due to public protests. In the 2016 census , Mount Coot-tha had
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3486-450: The atoms and ions in solid crystals to migrate, thus reorganizing the crystals, while high pressures cause solution of the crystals within the rock at their point of contact. Metamorphic rocks are characterized by their distinctive mineral composition and texture. Because every mineral is stable only within certain limits, the presence of certain minerals in metamorphic rocks indicates the approximate temperatures and pressures at which
3569-402: The crystallization of igneous rocks. They are stable at high temperatures and pressures and may remain chemically unchanged during the metamorphic process. Metamorphic rocks are typically more coarsely crystalline than the protolith from which they formed. Atoms in the interior of a crystal are surrounded by a stable arrangement of neighboring atoms. This is partially missing at the surface of
3652-808: The American or British use of "district" or "neighbourhood", and can be used to refer to any portion of a city. Unlike the use in British or American English, this term can include inner-city, outer-metropolitan and industrial areas. Localities existed in the past as informal units, but in 1996 the Intergovernmental Committee on Surveying and Mapping and the Committee for Geographical Names in Australasia (CGNA) decided to name and establish official boundaries for all localities and suburbs. There has subsequently been
3735-592: The City of Brisbane, such as: which are within the locality of Lake Manchester in the D'Aguilar National Park , but these are not accessible by road. For recreation and tourism purposes, Mount Coot-tha is the highest point in Brisbane which is easily accessed and has excellent views. The Brisbane Botanic Gardens are at the base of the mountain at 152 Mount Coot-tha Road ( 27°28′36″S 152°58′30″E / 27.4767°S 152.9751°E / -27.4767; 152.9751 ( Brisbane Botanic Gardens ) ). A number of other faciliites are on that site including
3818-666: The City. A function centre adjoins the restaurant. Well-known British astronomer Sir Patrick Moore gave a night-time public lecture about the stars of the southern hemisphere at the lookout in 1988, in conjunction with Patrick Moore being a guest speaker at a dinner of the Southern Astronomical Society at Toowong in Queensland. The Mount Coot-tha Reserve contains more than 1,500 hectares of natural bushland , including J C Slaughter Falls along Ithaca Creek , as well as native wildlife. Mount Coot-tha Reserve also shares
3901-827: The Mount Coot-tha Botanic Gardens and were officially opened in 1976, becoming the Brisbane Botanic Gardens with the gardens in the CBD being renamed the City Botanic Gardens ) .The new gardens cover 52 hectares (130 acres). The Mount Coot-tha Library opened in 1975 at the Brisbane Botanic Gardens . Unlike most branches of the Brisbane City Libraries, this library specialises in botany, horticulture, gardening and landscape design. On 24 May 1978, Sir Thomas Brisbane Planetarium officially opened in
3984-758: The Sir Thomas Brisbane Planetarium ( 27°28′32″S 152°58′37″E / 27.4756°S 152.9769°E / -27.4756; 152.9769 ( Sir Thomas Brisbane Planetarium ) ), the Mount Coot-tha branch of the Brisbane City Council Library ( 27°28′31″S 152°58′34″E / 27.4752°S 152.9760°E / -27.4752; 152.9760 ( Mount Coot-tha public library ) ), and Queensland Herbarium ( 27°28′32″S 152°58′33″E / 27.4756°S 152.9757°E / -27.4756; 152.9757 ( Queensland Herbarium ) ). Between
4067-477: The amphibolite or granulite facies. These form most of the exposed rock in Archean cratons. The granite-greenstone belts are intruded by a distinctive group of granitic rocks called the tonalite - trondhjemite - granodiorite or TTG suite. These are the most voluminous rocks in the craton and may represent an important early phase in the formation of continental crust. Mid-ocean ridges are where new oceanic crust
4150-495: The area to collect ku-ta , the Yugarabul word for honey that was produced by the native stingless bee . In 1839, surveyor James Warner and his team cleared the top of the mountain of all trees except one large eucalypt tree. Because this single tree could be seen from many other locations, it was used as a trigonometric station to take surveying measurements. This led to the mountain being called One Tree Hill . In 1873,
4233-404: The bands showing the colors of the minerals that formed them. Foliated rock often develops planes of cleavage . Slate is an example of a foliated metamorphic rock, originating from shale , and it typically shows well-developed cleavage that allows slate to be split into thin plates. The type of foliation that develops depends on the metamorphic grade. For instance, starting with a mudstone ,
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#17330851617644316-411: The botanic gardens and the mountain is the 26-hectare (64-acre) Mount Coot-tha Quarry at 200 Mount Coot-tha Road ( 27°28′38″S 152°58′09″E / 27.4773°S 152.9693°E / -27.4773; 152.9693 ( Mount Coot-tha Quarry ) ). It is operated by the Brisbane City Council. The quarry extracts metamorphic rock for both stonework and aggregate . Due to the hardness of
4399-420: The bulk composition of a rock. Hot fluids circulating through pore space in the rock can dissolve existing minerals and precipitate new minerals. Dissolved substances are transported out of the rock by the fluids while new substances are brought in by fresh fluids. This can obviously change the mineral makeup of the rock. However, changes in the mineral composition can take place even when the bulk composition of
4482-399: The burning of coal seams. This produces a rock type named clinker . There is also a tendency for metasomatism between the igneous magma and sedimentary country rock, whereby the chemicals in each are exchanged or introduced into the other. In that case, hybrid rocks called skarn arise. Dynamic (cataclastic) metamorphism takes place locally along faults . Here intense shearing of
4565-435: The circulation of fluids through buried rock, to the list of processes that help bring about metamorphism. However, metamorphism can take place without metasomatism ( isochemical metamorphism ) or at depths of just a few hundred meters where pressures are relatively low (for example, in contact metamorphism ). Metamorphic processes change the texture or mineral composition of the metamorphosed rock. Metasomatism can change
4648-427: The collision of tectonic plates at convergent boundaries . Here formerly deeply buried rock has been brought to the surface by uplift and erosion. The metamorphic rock exposed in orogenic belts may have been metamorphosed simply by being at great depths below the Earth's surface, subjected to high temperatures and the great pressure caused by the immense weight of the rock layers above. This kind of regional metamorphism
4731-486: The community television station Briz 31 . Most of the FM Brisbane radio stations also transmit from Mount Coot-tha. Part of the Brisbane suburb of The Gap is located on the foothills beneath the television towers. The Brisbane Botanic Gardens has a range of attractions featuring plants from different landscapes, including a tropical hothouse, a Japanese garden, an arid zone (plants from Central America and Africa), and
4814-500: The conditions under which the quarry operates would not be approved if it was being proposed today, but the principle of "existing industrial use" allows industrial activities to continue if they were acceptable at the time of their original establishment/approval. Suburbs and localities (Australia) Suburbs and localities are the names of geographic subdivisions in Australia , used mainly for address purposes. The term locality
4897-491: The contact area to unmetamorphosed (unchanged) country rock some distance away. The formation of important ore minerals may occur by the process of metasomatism at or near the contact zone. Contact aureoles around large plutons may be as much as several kilometers wide. The term hornfels is often used by geologists to signify those fine grained, compact, non-foliated products of contact metamorphism. The contact aureole typically shows little deformation, and so hornfels
4980-612: The crystal, producing a surface energy that makes the surface thermodynamically unstable. Recrystallization to coarser crystals reduces the surface area and so minimizes the surface energy. Although grain coarsening is a common result of metamorphism, rock that is intensely deformed may eliminate strain energy by recrystallizing as a fine-grained rock called mylonite . Certain kinds of rock, such as those rich in quartz, carbonate minerals , or olivine, are particularly prone to form mylonites, while feldspar and garnet are resistant to mylonitization. Many kinds of metamorphic rocks show
5063-423: The eclogite facies releases a great deal of water vapor from the rock, which drives volcanism in the overlying volcanic arc . Eclogite is also significantly denser than blueschist, which drives further subduction of the slab deep into the Earth's mantle . Metabasalt and blueschist may be preserved in blueschist metamorphic belts formed by collisions between continents. They may also be preserved by obduction onto
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#17330851617645146-438: The first instance, decisions about the names and boundaries of suburbs and localities are made by the local council in which they are located based on criteria such as community recognition. Local council decisions are, however, subject to approval by the state's geographical names board. The boundaries of some suburbs and localities overlap two or more local government areas (LGAs). Examples of this are Adamstown Heights , which
5229-437: The following sequence develops with increasing temperature: The mudstone is first converted to slate, which is a very fine-grained, foliated metamorphic rock, characteristic of very low grade metamorphism. Slate in turn is converted to phyllite , which is fine-grained and found in areas of low grade metamorphism. Schist is medium to coarse-grained and found in areas of medium grade metamorphism. High-grade metamorphism transforms
5312-697: The forests on the mountain were declared a timber reserve to supply timber for Queensland's growing railway network . The name Coot-tha replaced the name One Tree Hill when the area was declared a park in August 1883. The name was suggested by Henry Wyatt Radford, the Clerk of the Queensland Legislative Council , on the advice of local Aboriginal foreman Kerwalli . Coot-tha has been suggested as an Aboriginal word for honey . Archibald Meston ( Protector of Aborigines , 1898–1903) wrote in 1923 that Gootcha
5395-559: The grounds of the Brisbane Botanic Gardens . Brisbane community television channel 31 Digital broadcast from the mountain from 1994 to 2017, after which it shifted to internet streaming under the new name of Hitchhike TV . On 20 November 2005, one of the Mount Coot-tha more difficult trails, the Currawong trail , was renamed the Kokoda trail in honour of the Australian soldiers who marched
5478-449: The identical composition, Al 2 SiO 5 . Likewise, forsterite is stable over a broad range of pressure and temperature in marble , but is converted to pyroxene at elevated pressure and temperature in more silicate-rich rock containing plagioclase , with which the forsterite reacts chemically. Many complex high-temperature reactions may take place between minerals without them melting, and each mineral assemblage produced indicates
5561-585: The lookout. Mount Coot-tha was also the site of US Naval Ammunition Depot (Navy 134) supplying submarines at the Capricorn Wharf at New Farm ( Teneriffe ) in Brisbane. In 1970, Brisbane City Council established new botanic gardens at the base of the mountain with the intention of replacing the then Brisbane Botanic Gardens at Gardens Point in the Brisbane CBD , which was prone to flooding and lacked space for expansion. The new gardens were originally called
5644-437: The low-pressure facies, such as the hornfels and sanidinite facies . Most metamorphic rock is formed by regional metamorphism in the middle and lower crust, where the rock reaches the higher-pressure metamorphic facies. This rock is found at the surface only where extensive uplift and erosion has exhumed rock that was formerly much deeper in the crust. Metamorphic rock is extensively exposed in orogenic belts produced by
5727-460: The overriding plate as part of ophiolites . Eclogites are occasionally found at sites of continental collision, where the subducted rock is rapidly brought back to the surface, before it can be converted to the granulite facies in the hot upper mantle. Many samples of eclogite are xenoliths brought to the surface by volcanic activity. Many orogenic belts contain higher-temperature, lower-pressure metamorphic belts. These may form through heating of
5810-487: The quarry prior to moving to the area, that blasting is conducted at most twice a month with each blast lasting for less than 0.6 seconds, that blasts are conducted using blast minimisation techniques, and that blasts are within the guidelines established by the Queensland Government (which the government has confirmed). Residents can be advised of upcoming blasts by subscribing to an email list. Residents assert that
5893-545: The quarry was acquired by the Brisbane City Council. During World War II , the mountain was used as a military base by the RAAF and the US Navy . It was converted to a vast explosives depot and at one stage held more than 120,000 tonnes of explosive weapons. When darkness fell, the lookout bristled with search lights in an amazing display as soldiers kept an eye out for enemy planes . Anti-aircraft guns and searchlights were located on
5976-475: The rock by ascending magmas of volcanic arcs, but on a regional scale. Deformation and crustal thickening in an orogenic belt may also produce these kinds of metamorphic rocks. These rocks reach the greenschist , amphibolite, or granulite facies and are the most common of metamorphic rocks produced by regional metamorphosis. The association of an outer high-pressure, low-temperature metamorphic zone with an inner zone of low-pressure, high-temperature metamorphic rocks
6059-421: The rock does not change. This is possible because all minerals are stable only within certain limits of temperature, pressure, and chemical environment. For example, at atmospheric pressure, the mineral kyanite transforms to andalusite at a temperature of about 190 °C (374 °F). Andalusite, in turn, transforms to sillimanite when the temperature reaches about 800 °C (1,470 °F). All three have
6142-423: The rock to gneiss , which is coarse to very coarse-grained. Rocks that were subjected to uniform pressure from all sides, or those that lack minerals with distinctive growth habits, will not be foliated. Marble lacks platy minerals and is generally not foliated, which allows its use as a material for sculpture and architecture. Metamorphic rocks are one of the three great divisions of all rock types, and so there
6225-495: The rock typically forms mylonites. Impact metamorphism is unlike other forms of metamorphism in that it takes place during impact events by extraterrestrial bodies. It produces rare ultrahigh pressure metamorphic minerals, such as coesite and stishovite . Coesite is rarely found in eclogite brought to the surface in kimberlite pipes , but the presence of stishovite is unique to impact structures. Slate tiles are used in construction, particularly as roof shingle. Quartzite
6308-407: The rock underwent metamorphism. These minerals are known as index minerals . Examples include sillimanite , kyanite , staurolite , andalusite , and some garnet . Other minerals, such as olivines , pyroxenes , hornblende , micas , feldspars , and quartz , may be found in metamorphic rocks but are not necessarily the result of the process of metamorphism. These minerals can also form during
6391-486: The rock). Metasedimentary rocks are divided into carbonate-rich rock (metacarbonates or calcsilicate-rocks) or carbonate-poor rocks, and the latter are further classified by the relative abundance of mica in their composition. This ranges from low-mica psammite through semipelite to high-mica pelite . Psammites composed mostly of quartz are classified as quartzite. Metaigneous rocks are classified similarly to igneous rocks, by silica content, from meta-ultramafic-rock (which
6474-552: The rock, blasting can be required for extraction, but the hardness is beneficial as the building materials it creates are very durable . The quarry has provided the aggregates for over 96% of Brisbane's roads, producing approx 400,000 tonnes (440,000 tons) of aggregate for asphalt each year. Before the Moreton Bay penal settlement , Mount Coot-tha was the home of the Yugara Aboriginal people. The Aboriginal people came to
6557-406: The sedimentary rock limestone and chalk change into larger crystals in the metamorphic rock marble . In metamorphosed sandstone, recrystallization of the original quartz sand grains results in very compact quartzite, also known as metaquartzite, in which the often larger quartz crystals are interlocked. Both high temperatures and pressures contribute to recrystallization. High temperatures allow
6640-404: The temperatures and pressures at the time of metamorphism. These reactions are possible because of rapid diffusion of atoms at elevated temperature. Pore fluid between mineral grains can be an important medium through which atoms are exchanged. The change in the particle size of the rock during the process of metamorphism is called recrystallization . For instance, the small calcite crystals in
6723-451: The use of granulite as a classification for rock metamorphosed to the granulite facies. Instead, such rock will often be classified as a granofels. However, this approach is not universally accepted. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. The lower continental crust is mostly metamafic-rock and pelite which have reached the granulite facies . The middle continental crust
6806-511: The zonal schemes, based on index minerals, that were pioneered by the British geologist, George Barrow . The metamorphic facies is not usually considered when classifying metamorphic rock based on protolith, mineral mode, or texture. However, a few metamorphic facies produce rock of such distinctive character that the facies name is used for the rock when more precise classification is not possible. The chief examples are amphibolite and eclogite . The British Geological Survey strongly discourages
6889-419: Was important in metamorphism. This hypothesis was tested by his friend, James Hall , who sealed chalk into a makeshift pressure vessel constructed from a cannon barrel and heated it in an iron foundry furnace. Hall found that this produced a material strongly resembling marble , rather than the usual quicklime produced by heating of chalk in the open air. French geologists subsequently added metasomatism ,
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