Great Artesian Basin
The Great Artesian Basin, located in Australia, is the largest and deepest artesian basin in the world, stretching over 1,700,000 square kilometres, with measured water temperatures ranging from 30–100 °C. The basin provides the only source of fresh water through much of inland Australia; the Basin underlies 22% of the continent, including the states and territories of Queensland, the Northern Territory, South Australia, New South Wales. The basin is 3,000 metres deep in places and is estimated to contain 64,900 cubic kilometres of groundwater; the Great Artesian Basin Coordinating Committee coordinates activity between the various levels of government and community organisations. This area is one of the distinct physiographic provinces of the larger East Australian Basins division, includes the smaller Wilcannia Threshold physiographic section; the water of the GAB is held in a sandstone layer laid down by continental erosion of higher ground during the Triassic and early Cretaceous periods.
During a time when much of what is now inland Australia was below sea level, the sandstone was covered by a layer of marine sedimentary rock shortly afterward, which formed a confining layer, thus trapping water in the sandstone aquifer. The eastern edge of the basin was uplifted; the other side was created from the landforms of the Central Eastern Lowlands and the Great Western Plateau to the west. Most recharge water enters the rock formations from high ground near the eastern edge of the basin and gradually flows toward the south and west. A much smaller amount enters along the western margin in arid central Australia, flowing to the south and east; because the sandstones are permeable, water makes its way through the pores between the sand grains, flowing at a rate of one to five metres per year. Discharge water exits through a number of springs and seeps in the southern part of the basin; the age of the groundwater determined by carbon-14 and chlorine-36 measurements combined with hydraulic modelling ranges from several thousand years for the recharge areas in the north to nearly 2 million years in the south-western discharge zones.
Prior to European occupation, waters of the GAB discharged through mound springs, many in arid South Australia. These springs supported a variety of endemic invertebrates, supported extensive Aboriginal communities and trade routes. After the arrival of Europeans, they enabled early exploration and faster communications between southeastern Australia and Europe via the Australian Overland Telegraph Line; the Great Artesian Basin became an important water supply for cattle stations and livestock and domestic usage, is a vital life line for rural Australia. To tap it, water wells are drilled down to a suitable rock layer, where the pressure of the water forces it up without pumping; the discovery and use of water held underground in the Great Artesian Basin opened up thousands of square miles of country away from rivers in inland New South Wales and South Australia unavailable for pastoral activities. European discovery of the basin dates from 1878 when a shallow bore near Bourke produced flowing water.
There were similar discoveries in 1886 at Back Creek east of Barcaldine, in 1887 near Cunnamulla. In essence, water extraction from the GAB is a mining operation, with recharge much less than current extraction rates. In 1915, there were 1,500 bores providing 2,000 megalitres of water per day, but today the total output has dropped to 1,500 megalitres per day; this included just under 2000 flowing bores and more than 9000 that required mechanical power to bring water to the surface. Many bores abandoned, resulting in considerable water wastage; these problems have existed for many decades, in January 2007 the Australian Commonwealth Government announced additional funding in an attempt to bring them under control. However, many of the mound springs referred to above have dried up due to a drop in water pressure resulting in extinction of several invertebrate species; the Olympic Dam mine in South Australia is permitted to extract up to 42 million litres of water daily from the Great Artesian Basin under the Roxby Downs Act 1982.
The underground copper and uranium mine commenced operations in 1988 and is expected to continue operating until 2060. In addition, the basin has provided water via a 1.2 km deep bore for a geothermal power station at Birdsville. The heated water provides 25 % of the town's needs. Ergon Energy is expanding the 80 kW plant to meet Birdsville's electricity requirements; as the Great Artesian Basin underlies parts of Queensland, New South Wales, South Australia and the Northern Territory, which each operate under different legislative frameworks and resource management approaches, a coordinated "whole-of-Basin" approach to the management of this important natural resource is required. The Great Artesian Basin Coordinating Committee provides advice from community organisations and agencies to State and Australian Government Ministers on efficient and sustainable whole-of-Basin resource management and to coordinate activity between stakeholders. Membership of the Committee comprises all State and Australian Government agencies with responsibilities for management of parts of the Great Artesian Basin, community representatives nominated by agencies.
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Geology is an earth science concerned with the solid Earth, the rocks of which it is composed, the processes by which they change over time. Geology can include the study of the solid features of any terrestrial planet or natural satellite such as Mars or the Moon. Modern geology overlaps all other earth sciences, including hydrology and the atmospheric sciences, so is treated as one major aspect of integrated earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface, the processes that have shaped that structure, it provides tools to determine the relative and absolute ages of rocks found in a given location, to describe the histories of those rocks. By combining these tools, geologists are able to chronicle the geological history of the Earth as a whole, to demonstrate the age of the Earth. Geology provides the primary evidence for plate tectonics, the evolutionary history of life, the Earth's past climates. Geologists use a wide variety of methods to understand the Earth's structure and evolution, including field work, rock description, geophysical techniques, chemical analysis, physical experiments, numerical modelling.
In practical terms, geology is important for mineral and hydrocarbon exploration and exploitation, evaluating water resources, understanding of natural hazards, the remediation of environmental problems, providing insights into past climate change. Geology is a major academic discipline, it plays an important role in geotechnical engineering; the majority of geological data comes from research on solid Earth materials. These fall into one of two categories: rock and unlithified material; the majority of research in geology is associated with the study of rock, as rock provides the primary record of the majority of the geologic history of the Earth. There are three major types of rock: igneous and metamorphic; the rock cycle illustrates the relationships among them. When a rock solidifies or crystallizes from melt, it is an igneous rock; this rock can be weathered and eroded redeposited and lithified into a sedimentary rock. It can be turned into a metamorphic rock by heat and pressure that change its mineral content, resulting in a characteristic fabric.
All three types may melt again, when this happens, new magma is formed, from which an igneous rock may once more solidify. To study all three types of rock, geologists evaluate the minerals; each mineral has distinct physical properties, there are many tests to determine each of them. The specimens can be tested for: Luster: Measurement of the amount of light reflected from the surface. Luster is broken into nonmetallic. Color: Minerals are grouped by their color. Diagnostic but impurities can change a mineral’s color. Streak: Performed by scratching the sample on a porcelain plate; the color of the streak can help name the mineral. Hardness: The resistance of a mineral to scratch. Breakage pattern: A mineral can either show fracture or cleavage, the former being breakage of uneven surfaces and the latter a breakage along spaced parallel planes. Specific gravity: the weight of a specific volume of a mineral. Effervescence: Involves dripping hydrochloric acid on the mineral to test for fizzing. Magnetism: Involves using a magnet to test for magnetism.
Taste: Minerals can have a distinctive taste, like halite. Smell: Minerals can have a distinctive odor. For example, sulfur smells like rotten eggs. Geologists study unlithified materials, which come from more recent deposits; these materials are superficial deposits. This study is known as Quaternary geology, after the Quaternary period of geologic history. However, unlithified material does not only include sediments. Magmas and lavas are the original unlithified source of all igneous rocks; the active flow of molten rock is studied in volcanology, igneous petrology aims to determine the history of igneous rocks from their final crystallization to their original molten source. In the 1960s, it was discovered that the Earth's lithosphere, which includes the crust and rigid uppermost portion of the upper mantle, is separated into tectonic plates that move across the plastically deforming, upper mantle, called the asthenosphere; this theory is supported by several types of observations, including seafloor spreading and the global distribution of mountain terrain and seismicity.
There is an intimate coupling between the movement of the plates on the surface and the convection of the mantle. Thus, oceanic plates and the adjoining mantle convection currents always move in the same direction – because the oceanic lithosphere is the rigid upper thermal boundary layer of the convecting mantle; this coupling between rigid plates moving on the surface of the Earth and the convecting mantle is called plate tectonics. The development of plate tectonics has provided a physical basis for many observations of the solid Earth. Long linear regions of geologic features are explained as plate boundaries. For example: Mid-ocean ridges, high regions on the seafloor where hydrothermal vents and volcanoes exist, are seen as divergent boundaries, where two plates move apart. Arcs of volcanoes and earthquakes are theorized as convergent boundaries, where one plate subducts, or moves, under another. Transform boundaries, such as the San Andreas Fault system, resulted in widespread powerful earthquakes.
Plate tectonics has provided a mechan
The Carboniferous is a geologic period and system that spans 60 million years from the end of the Devonian Period 358.9 million years ago, to the beginning of the Permian Period, 298.9 Mya. The name Carboniferous means "coal-bearing" and derives from the Latin words carbō and ferō, was coined by geologists William Conybeare and William Phillips in 1822. Based on a study of the British rock succession, it was the first of the modern'system' names to be employed, reflects the fact that many coal beds were formed globally during that time; the Carboniferous is treated in North America as two geological periods, the earlier Mississippian and the Pennsylvanian. Terrestrial animal life was well established by the Carboniferous period. Amphibians were the dominant land vertebrates, of which one branch would evolve into amniotes, the first terrestrial vertebrates. Arthropods were very common, many were much larger than those of today. Vast swaths of forest covered the land, which would be laid down and become the coal beds characteristic of the Carboniferous stratigraphy evident today.
The atmospheric content of oxygen reached its highest levels in geological history during the period, 35% compared with 21% today, allowing terrestrial invertebrates to evolve to great size. The half of the period experienced glaciations, low sea level, mountain building as the continents collided to form Pangaea. A minor marine and terrestrial extinction event, the Carboniferous rainforest collapse, occurred at the end of the period, caused by climate change. In the United States the Carboniferous is broken into Mississippian and Pennsylvanian subperiods; the Mississippian is about twice as long as the Pennsylvanian, but due to the large thickness of coal-bearing deposits with Pennsylvanian ages in Europe and North America, the two subperiods were long thought to have been more or less equal in duration. In Europe the Lower Carboniferous sub-system is known as the Dinantian, comprising the Tournaisian and Visean Series, dated at 362.5-332.9 Ma, the Upper Carboniferous sub-system is known as the Silesian, comprising the Namurian and Stephanian Series, dated at 332.9-298.9 Ma.
The Silesian is contemporaneous with the late Mississippian Serpukhovian plus the Pennsylvanian. In Britain the Dinantian is traditionally known as the Carboniferous Limestone, the Namurian as the Millstone Grit, the Westphalian as the Coal Measures and Pennant Sandstone; the International Commission on Stratigraphy faunal stages from youngest to oldest, together with some of their regional subdivisions, are: A global drop in sea level at the end of the Devonian reversed early in the Carboniferous. There was a drop in south polar temperatures; these conditions had little effect in the deep tropics, where lush swamps to become coal, flourished to within 30 degrees of the northernmost glaciers. Mid-Carboniferous, a drop in sea level precipitated a major marine extinction, one that hit crinoids and ammonites hard; this sea level drop and the associated unconformity in North America separate the Mississippian subperiod from the Pennsylvanian subperiod. This happened about 323 million years ago, at the onset of the Permo-Carboniferous Glaciation.
The Carboniferous was a time of active mountain-building as the supercontinent Pangaea came together. The southern continents remained tied together in the supercontinent Gondwana, which collided with North America–Europe along the present line of eastern North America; this continental collision resulted in the Hercynian orogeny in Europe, the Alleghenian orogeny in North America. In the same time frame, much of present eastern Eurasian plate welded itself to Europe along the line of the Ural Mountains. Most of the Mesozoic supercontinent of Pangea was now assembled, although North China, South China continents were still separated from Laurasia; the Late Carboniferous Pangaea was shaped like an "O." There were two major oceans in the Carboniferous—Panthalassa and Paleo-Tethys, inside the "O" in the Carboniferous Pangaea. Other minor oceans were shrinking and closed - Rheic Ocean, the small, shallow Ural Ocean and Proto-Tethys Ocean. Average global temperatures in the Early Carboniferous Period were high: 20 °C.
However, cooling during the Middle Carboniferous reduced average global temperatures to about 12 °C. Lack of growth rings of fossilized trees suggest a lack of seasons of a tropical climate. Glaciations in Gondwana, triggered by Gondwana's southward movement, continued into the Permian and because of the lack of clear markers and breaks, the deposits of this glacial period are referred to as Permo-Carboniferous in age; the cooling and drying of the climate led to the Carboniferous Rainforest Collapse during the late Carboniferous. Tropical rainforests fragmented and were devastated by climate change. Carboniferous rocks in Europe and eastern North America consist of a repeated sequence of limestone, sandstone and coal beds. In North America, the early Carboniferous is marine
The Northern Territory is an Australian territory in the central and central northern regions of Australia. It shares borders with Western Australia to the west, South Australia to the south, Queensland to the east. To the north, the territory looks out to the Timor Sea, the Arafura Sea and the Gulf of Carpentaria, including Western New Guinea and other Indonesian islands; the NT covers 1,349,129 square kilometres, making it the third-largest Australian federal division, the 11th-largest country subdivision in the world. It is sparsely populated, with a population of only 246,700, making it the least-populous of Australia's eight states and major territories, with fewer than half as many people as Tasmania; the archaeological history of the Northern Territory begins over 40,000 years ago when Indigenous Australians settled the region. Makassan traders began trading with the indigenous people of the Northern Territory for trepang from at least the 18th century onwards; the coast of the territory was first seen by Europeans in the 17th century.
The British were the first Europeans to attempt to settle the coastal regions. After three failed attempts to establish a settlement, success was achieved in 1869 with the establishment of a settlement at Port Darwin. Today the economy is based on tourism Kakadu National Park in the Top End and the Uluṟu-Kata Tjuṯa National Park in central Australia, mining; the capital and largest city is Darwin. The population is concentrated along the Stuart Highway; the other major settlements are Palmerston, Alice Springs, Katherine and Tennant Creek. Residents of the Northern Territory are known as "Territorians" and as "Northern Territorians", or more informally as "Top Enders" and "Centralians". Indigenous Australians have lived in the present area of the Northern Territory for an estimated 40,000 years, extensive seasonal trade links existed between them and the peoples of what is now Indonesia for at least five centuries. With the coming of the British, there were four early attempts to settle the harsh environment of the northern coast, of which three failed in starvation and despair.
The Northern Territory was part of colonial New South Wales from 1825 to 1863, except for a brief time from February to December 1846, when it was part of the short-lived colony of North Australia. It was part of South Australia from 1863 to 1911. Under the administration of colonial South Australia, the overland telegraph was constructed between 1870 and 1872. From its establishment in 1869 the Port of Darwin was the major Territory supply for many decades. A railway was built between Palmerston and Pine Creek between 1883 and 1889; the economic pattern of cattle raising and mining was established so that by 1911 there were 513,000 cattle. Victoria River Downs was at one time the largest cattle station in the world. Gold was found at Grove Hill in 1872 and at Pine Creek, Brocks Creek and copper was found at Daly River. On 1 January 1911, a decade after federation, the Northern Territory was separated from South Australia and transferred to federal control. Alfred Deakin opined at this time "To me the question has been not so much commercial as national, second and last.
Either we must accomplish the peopling of the northern territory or submit to its transfer to some other nation." In late 1912 there was growing sentiment. The names "Kingsland", "Centralia" and "Territoria" were proposed with Kingsland becoming the preferred choice in 1913. However, the name change never went ahead. For a brief time between 1927 and 1931 the Northern Territory was divided into North Australia and Central Australia at the 20th parallel of South latitude. Soon after this time, parts of the Northern Territory were considered in the Kimberley Plan as a possible site for the establishment of a Jewish Homeland, understandably considered the "Unpromised Land". During World War II, most of the Top End was placed under military government; this is the only time since Federation that part of an Australian state or territory has been under military control. After the war, control for the entire area was handed back to the Commonwealth; the Bombing of Darwin occurred on 19 February 1942. It was the largest single attack mounted by a foreign power on Australia.
Evidence of Darwin's World War II history is found at a variety of preserved sites in and around the city, including ammunition bunkers, oil tunnels and museums. The port was damaged in the 1942 Japanese air raids, it was subsequently restored. In the late 1960s improved roads in adjoining States linking with the territory, port delays and rapid economic development led to uncertainty in port and regional infrastructure development; as a result of the Commission of Enquiry established by the Administrator, port working arrangements were changed, berth investment deferred and a port masterplan prepared. Extension of rail transport was not considered because of low freight volumes. Indigenous Australians had struggled for rights to fair wages and land. An important event in this struggle was the strike and walk off by the Gurindji people at Wave Hill Cattle Station in 1966; the federal government of Gough Whitlam set up the Woodward Royal Commission in February 1973, which set to enquire into how land rights might be achieved in the Northern Territory.
Justice Woodward's first report in July 1973 recommended that a Central Land Council and a Northern Land Council be established to present to him the views of
The Larapinta Trail is an extended walking track in the Northern Territory, Australia. Its total length covers 223 kilometres from east to west, with the eastern end at Alice Springs and the western end at Mount Sonder, one of the territory's highest mountains, it follows the West MacDonnell Ranges, sometimes along the ridge line, other times on the plain below, in the West MacDonnell National Park. Finke River Simpsons Gap Standley Chasm Ellery Creek Bighole Serpentine Gorge Ochre Pits Ormiston Pound Redbank Gorge Glen Helen Gorge The walk harbours many Aboriginal sacred sites of the Arrernte people, who have permitted tourists to visit the sites. In the 1990s the walk was only half as long, with the section between Mount Sonder and Ellery Big Hole completed at the turn of the millennium. Presently, the Northern Territory government is advertising the walk as Australia's best extended walk, competing with Western Australia's Bibbulmun Track and Tasmania's Overland Track and Western Arthurs track.
The original Larapinta trail plan was to end at Mount Zeil on the Western end of the West MacDonnell National Park. The terrain from Mount Sonder to Mount Zeil being hard to access by vehicle for rescue operations, the trail stopped at Mount Sonder. In September 2006, Belgian adventurer Louis-Philippe Loncke walked without resupply from West of Mount Zeil to Alice Springs walking off track and joining the Larapinta trail at Redbank gorge. On the 16th August 2014 Jessica Baker and Meredith Quinlan set a new record arriving at the Alice Springs Telegraph Station in 60 hours and 59 minutes, without crew and only the aid of drop boxes left at 3 locations en route; the trail is well marked with kilometre posts marking both the distance to the next campsite or section as well as the total length of the walk to go. There is a published leaflet that details the requirements and attractions of completing each of the twelve sections and notice boards at the transition of each section; these notice boards show elevation graphs of the walk and alert walkers to potential dangers.
There is a reasonable amount of water along the track, both found and trucked in. There are only one or two places in which water cannot be obtained throughout the day, with frequent storage tanks. Signage suggests that all water should be treated by boiling it for 5 minutes or adding water treatment tablets. No fires are allowed along the walk. There are now APP mapped walk information for the Larapinta; these can provide a useful backup to your maps. During the summer months, temperatures along the trail can exceed 45 °C, leading to danger of heatstroke and dehydration. Most people walk the trail during winter. MacDonnell Ranges Guided Larapinta Trail Walks Australia's Premier Larapinta Trail Website Northern Territory Parks and Wilderness Commission information TravelNT and TourismNT Website Friends of the Larapinta Trail Official West MacDonnell National Park Website Guthook Guides App Larapinta Trail
A meander is one of a series of regular sinuous curves, loops, turns, or windings in the channel of a river, stream, or other watercourse. It is produced by a stream or river swinging from side to side as it flows across its floodplain or shifts its channel within a valley. A meander is produced by a stream or river as it erodes the sediments comprising an outer, concave bank and deposits this and other sediment downstream on an inner, convex bank, a point bar; the result of sediments being eroded from the outside concave bank and their deposition on an inside convex bank is the formation of a sinuous course as a channel migrates back and forth across the down-valley axis of a floodplain. The zone within which a meandering stream shifts its channel across either its floodplain or valley floor from time to time is known as a meander belt, it ranges from 15 to 18 times the width of the channel. Over time, meanders migrate downstream, sometimes in such a short time as to create civil engineering problems for local municipalities attempting to maintain stable roads and bridges.
The degree of meandering of the channel of a river, stream, or other watercourse is measured by its sinuosity. The sinuosity of a watercourse is the ratio of the length of the channel to the straight line down-valley distance. Streams or rivers with a single channel and sinuosities of 1.5 or more are defined as meandering streams or rivers. The term derives from the Meander River located in present-day Turkey and known to the Ancient Greeks as Μαίανδρος Maiandros, characterised by a convoluted path along the lower reach; as a result in Classical Greece the name of the river had become a common noun meaning anything convoluted and winding, such as decorative patterns or speech and ideas, as well as the geomorphological feature. Strabo said: ‘…its course is so exceedingly winding that everything winding is called meandering.’The Meander River is south of Izmir, east of the ancient Greek town of Miletus, now Milet, Turkey. It flows through a graben in the Menderes Massif, but has a flood plain much wider than the meander zone in its lower reach.
Its modern Turkish name is the Büyük Menderes River. When a fluid is introduced to an straight channel which bends, the sidewalls induce a pressure gradient that causes the fluid to alter course and follow the bend. From here, two opposing processes occur: secondary flow. For a river to meander, secondary flow must dominate. Irrotational flow: From Bernoulli's equations, high pressure results in low velocity. Therefore, in the absence of secondary flow we would expect low fluid velocity at the outside bend and high fluid velocity at the inside bend; this classic fluid mechanics result is irrotational vortex flow. In the context of meandering rivers, its effects are dominated by those of secondary flow. Secondary flow: A force balance exists between pressure forces pointing to the inside bend of the river and centrifugal forces pointing to the outside bend of the river. In the context of meandering rivers, a boundary layer exists within the thin layer of fluid that interacts with the river bed. Inside that layer and following standard boundary-layer theory, the velocity of the fluid is zero.
Centrifugal force, which depends on velocity, is therefore zero. Pressure force, remains unaffected by the boundary layer. Therefore, within the boundary layer, pressure force dominates and fluid moves along the bottom of the river from the outside bend to the inside bend; this initiates helicoidal flow: Along the river bed, fluid follows the curve of the channel but is forced toward the inside bend. The downstream velocity of the fluid is convectively transported to the outside bend, resulting in higher velocities at the outside bend; this secondary flow effect dominates over that of irrotational flow: In real meandering rivers, we observe higher downstream fluid velocities at the outside bends. The higher velocities at the outside bend result in higher shear stresses and therefore results in erosion, thus meander bends erode at the outside bend, causing the river to becoming sinuous. Deposition at the inside bend occur such that for most natural meandering rivers, the river width remains nearly constant as the river evolves.
Where the is not forced to bend by a natural obstacle, Coriolis force of the earth can cause a small imbalance in velocity distribution such that velocity on one bank is higher than on the other. This can trigger deposition of sediment on the other; the technical description of a meandering watercourse is termed meander geometry or meander planform geometry. It is characterized as an irregular waveform. Ideal waveforms, such as a sine wave, are one line thick, but in the case of a stream the width must be taken into consideration; the bankfull width is the distance across the bed at an average cross-section at the full-stream level estimated by the line of lowest vegetation. As a waveform the meandering stream follows the down-valley axis, a straight line fitted to the curve such that the sum of all the amplitudes measured from it is zero; this axis represents the overall direction of the stream. At any cross-section the flow is following the centerline of the bed. Two consecutive crossing points of sinuous and down-valley axes define a meander loop.
The meander is two consecutive loops pointing in opposite transverse directions. The distance of one meander alo
Larapinta is a suburb located in the southern regions of Brisbane, on the boundary with Logan City. At the 2011 census the suburb had no residents, being bushland, save for the recent industrial development; the industrial area has become a new addition to the expansion of Brisbane's industry, including the purpose built South Brisbane Industrial Park in nearby Heathwood. Larapinta means "flowing water" and was so named because the north and west of the suburb is bounded by Oxley Creek. Sand mining has occurred in the area, resulting in a change of course for the main stream of the creek; the Sydney–Brisbane rail corridor passes along the eastern border of the suburb. The Logan Motorway bisects the suburb in an east/west direction. In the south the Glider Forest Conservation Area has been created to protect a large tract of bushland