Dreamtime is a term devised by early anthropologists to refer to a religio-cultural worldview attributed to Australian Aboriginal beliefs. It was used by Francis Gillen adopted by his colleague Baldwin Spencer and thereafter popularised by A. P. Elkin, however revised his views; the Dreaming is used to represent Aboriginal concepts of "time out of time" or "everywhen", during which the land was inhabited by ancestral figures of heroic proportions or with supernatural abilities. These figures were distinct from "gods" as they did not control the material world and were not worshipped, but only revered; the concept of the dreamtime has subsequently become adopted beyond its original Australian context and is now part of global popular culture. The term is based on a rendition of the indigenous word alcheringa, used by the Aranda people of Central Australia, although it has been argued that it is based on a misunderstanding or mistranslation; some scholars suggest that the word's meaning is closer to "eternal, uncreated."
Anthropologist William Stanner remarked: "why the blackfellow thinks of'dreaming' as the nearest equivalent in English is a puzzle", said that the concept was best understood by non-Aboriginal people as "a complex of meanings". By the 1990s, "Dreamtime" and "the Dreaming" had acquired their own currency in popular culture, based on idealised or fictionalised conceptions of Australian mythology. Since the 1970s, "Dreaming" and "Dream time" have returned from academic usage via popular culture and tourism and are now ubiquitous in the English vocabulary of indigenous Australians in a kind of "self-fulfilling academic prophecy"; the station-master and amateur ethnographer Francis Gillen first used the terms in an ethnographical report in 1896. With Walter Baldwin Spencer, Gillen published a major work, Native Tribes of Central Australia, in 1899. In that work, they spoke of the Alcheringa as "the name applied to the far distant past with which the earliest traditions of the tribe deal". Five years in their Northern tribes of central Australia, they gloss the far distant age as "the dream times", link it to the word alcheri meaning "dream", affirm that the term is current among the Kaitish and Unmatjera.
Early doubts about the precision of Spencer and Gillen's English gloss were expressed by the German Lutheran pastor and missionary Carl Strehlow in his 1908 book Die Aranda, who noted that his Arrente contacts explained altjira, whose etymology was unknown, as an eternal being who had no beginning. In the Arrernte tongue, the proper verb for "to dream" was altjirerama, i.e. "to see god". Strehlow theorised that the noun is the somewhat rare word altjirrinja, of which Spencer and Gillen gave a corrupted transcription and a false etymology. "The native," they concluded, "knows nothing of'dreamtime' as a designation of a certain period of their history."Strehlow gives Altjira or Altjira mara as the Arrente word for the eternal creator of the world and humankind. Strehlow describes him as a tall strong man with red skin, long fair hair and emu legs, with many red-skinned wives and children. In Strehlow's account, Altjira lives in the sky. However, by the time Strehlow was writing, his contacts had been converts to Christianity for decades, critics suggested that Altjira had been used by missionaries as a word for the Christian God.
In 1926, Spencer conducted a field study to challenge Strehlow's conclusion about Altjira and the implied criticism of Gillen and Spencer's original work. Spencer found attestations of altjira from the 1890s that used the word to mean "associated with past times" or "eternal", not "god". Academic Sam Gill finds Strehlow's use of Altjira ambiguous, sometimes describing a supreme being and sometimes describing a totem being, but not a supreme one, he attributes the clash to Spencer's cultural evolutionist beliefs that Aboriginal people were at a pre-religion "stage" of development, while Strehlow as a Christian missionary found presence of belief in the divine a useful entry point for proselytising. Linguist David Campbell Moore is critical of Spencer and Gillen's "Dreamtime" translation, concluding: "Dreamtime" was a mistranslation based on an etymological connection between "a dream" and "Altjira" which held only over a limited geographical domain. There was some semantic relationship between "Altjira" and "a dream", but to imagine that the latter captures the essence of "Altjira" is an illusion.
The complex of religious beliefs encapsulated by "Dreamtime" is called: "Ngarrankarni" or "Ngarrarngkarni" by the Gija people "the Jukurrpa" or "Tjukurpa" by the Warlpiri people and in the Pitjantjatjara dialect "the Ungud" or "Wungud" by the Ngarinyin people "Manguny" in the language Martu Wangka "Wongar" in North-East Arnhem Land "Daramoolen" in Ngunnawal language and Ngarigo language "Nura" in the Dharug languageIn English, anthropologists have variously translated words translated as "Dreamtime" or "Dreaming" in a variety of other ways, including "everywhen", "world-dawn", "Ancestral past", "Ancestral present", "Ancestral now", "Abiding Events" or "Abiding Law". Most translations of "Dreamtime" into other languages are based on the translation of the word "dream". Examples include Espaces de rêves in Snivanje in Croation. Related entities are known as Mura-mura as Tjukurpa in Pitjantjatjara. "Dreaming" is now used as a term for a system of totemic symbols, so that an indigenous Australian may "own" a spe
The Rainbow Serpent or Rainbow Snake is a common deity seen as a creator god and a common motif in the art and religion of Aboriginal Australia. It is named for the identification between that of a snake; some scholars believe that the link between snake and rainbow suggests the cycle of the seasons and the importance of water in human life. When the rainbow is seen in the sky, it is said to be the Rainbow Serpent moving from one waterhole to another, the divine concept explained why some waterholes never dried up when drought struck. There are innumerable names and stories associated with the serpent, all of which communicate the significance and power of this being within Aboriginal traditions, it is viewed as a giver of life, through its association with water, but can be a destructive force if angry. The Rainbow Serpent is one of the most common and well known Aboriginal stories, is of great importance to Aboriginal society; the Rainbow Serpent is one of the oldest continuing religious beliefs in the world and continues to be a cultural influence today.
The Rainbow Serpent is known by different names by different Aboriginal sub-cultures. The Rainbow Serpent is known as Borlung by the Miali, Dhakkan by the Kuli, Kajura by the Ingarda, Goorialla by the Lardil people, Kunmanggur by the Murinbata, Ngalyod by the Gunwinggu, Numereji by the Kakadu, Taipan by the Wikmunkan, Tulloun by the Mitakoodi, Wagyl by the Noongar, Wanamangura by the Talainji, Witij by the Yolngu. Other names include Bolung, Julunggul, Langal, Muit, Wollunqua, Wonungar, Yero and Yurlunggur. Though the concept of the Rainbow Serpent has existed for a long time in Aboriginal Australian cultures, it was introduced to the wider world through the work of anthropologists. In fact, the name Rainbow Serpent or Rainbow Snake appears to have been coined in English by Alfred Radcliffe-Brown, an anthropologist who noticed the same concept going under different names among various Aboriginal Australian cultures, called it "the rainbow-serpent myth of Australia", it has been suggested that this name implies that there is only one Rainbow Serpent, when the concept varies quite a bit from one Aboriginal culture to another, should be properly called the Rainbow Serpent myths of Australia.
It has been suggested that the Serpent's position as the most prominent creator god in the Australian tradition has been the creation of non-Aboriginal anthropologists. Another error of the same kind is the way in which Western-educated people, with a cultural stereotype of Greco-Roman or Norse myths, tell the Aboriginal stories in the past tense. For the indigenous people of Australia, the stories are "Everywhen" — past and future. Dreamtime stories tell of the great spirits and totems during creation, in animal and human form that moulded the barren and featureless earth; the Rainbow Serpent came from beneath the ground and created huge ridges and gorges as it pushed upward. The Rainbow Serpent is understood to be of immense proportions and inhabits deep permanent waterholes and is in control of life's most precious resource, water. In some cultures, the Rainbow Serpent is considered to be the ultimate creator of everything in the universe. In some cultures, the Rainbow Serpent is male; some commentators have suggested that the Rainbow Serpent is a phallic symbol, which fits its connection with fertility myths and rituals.
When the Serpent is characterized as female or bisexual, it is sometimes depicted with breasts. Other times, the Serpent has no particular gender; the Serpent has been known to appear as a scorpion or another animal or creature. In some stories, the Serpent is associated with a bat, sometimes called a "flying fox" in Australian English, engaged in a rivalry over a woman; some scholars have identified other creatures, such as a bird, dingo, or lizard, as taking the role of the Serpent in stories. In all cases, these animals are associated with water; the Rainbow Serpent has been identified with the bunyip, a fearful, water-hole dwelling creature in Australian mythology. The sometimes unpredictable Rainbow Serpent replenishes the stores of water, forming gullies and deep channels as the Rainbow Serpent slithers across the landscape. In this belief system, without the Serpent, no rain would fall and the Earth would dry up. In other cultures, the Serpent is said to come to stop the rain. In addition to the identification with the rainbow, the Serpent is identified with a prismatic halo around the moon that can be regarded as a sign of rain.
The Rainbow Serpent is sometimes associated with human blood circulation and the menstrual cycle, considered a healer. Thunder and lightning are said to stem from when the Rainbow Serpent is angry, the Serpent can cause powerful rainstorms and cyclones. Quartz crystal and seashells are associated with the Rainbow Serpent and are used in rituals to invoke it; the identification with quartz crystal results from its prism-like appearance. Stories about the Rainbow Serpent have been passed down from generation to generation; the Serpent story may vary however, according to environmental differences. Tribes of the monsoonal areas depict an epic interaction of the sun and wind in their Dreamtime stories, whereas tribes of the central desert experience less drastic seasonal shifts and their stories reflect this, it is known both as a ben
Vulkathunha-Gammon Ranges National Park
The Vulkathunha-Gammon Ranges National Park is a protected area in the Australian state of South Australia located in the northern Flinders Ranges southwest of and adjacent to the Arkaroola Protection Area. They encompass some of the most spectacular country in South Australia; the central ranges are of a different topographical nature to the rest of the Flinders, being composed of flat-lying strata, creating a high plateau into which spectacular gorges have been cut, instead of the buckled and folded strata further south which lead to the ubiquitous cuestas of Wilpena Pound. The Gammons are dominated by "The Plateau" in the southwest, contiguous with and of much the same height as the Blue Range further northeast, culminating in Benbonyathe Hill, the highest point in the Flinders north of Wilpena. Other summits on the flat range and plateau include Elephant Hill, Mount Changeweather, Four Winds Hill, Prow Point. Of these "rounded hills" of the plateau, Warren Bonython writes that "at their edge the slope, gentle near the crest, progressively steepens and changes into a precipice plunging down to a rock-strewn creek bed a thousand feet below" Some of the features of the ranges are the deep gorges cut in the south-eastern side of the Blue Range: Bunyip Chasm, The Terraces, Fern Chasm are all areas visited by bushwalkers.
Although lower than the mountains which surround it on three sides, the dramatic Cleft Peak is often visited, so-named for a spectacular cleft separating it into two summits, providing opportunities for rockclimbing to a summit, not necessary with peaks in the Flinders. The high central range and plateau is surrounded by a number of smaller outlying ranges, creating the encircling "pounds" of low hills: Balcanoona Range encloses Illinawortina Pound to the east, Mainwater Pound is to the north, enclosed by the Yankaninna Range, Arcoona Pound to the west. There are several major mountains on the margin of the Gammons, two of which are higher the main range: Gammon Hill in the north, overlooking Mainwater and Arcoona Pounds, Mount McKinlay dominating the south; the local Aboriginal people are the Adnyamathanha. The current generation live on the neighbouring station of Mount Serle and Aboriginal lands at Nepabunna and Nantawarrina; the national park is managed under a co-operative system which involves Adnyamathanha people in the running of the national park.
Included in the national park is a wide strip of territory running 40 km from the edge of the ranges to the shores of Lake Frome, an area, used by the local Aboriginal people for hunting kangaroos and emus. Curiously, regarding the mining controversies attendant with the national park, this area of the national park is traversed by the Moomba Adelaide Pipeline System gas pipeline; the first European to see the ranges was Edward Eyre on his 1840 expedition along the western side of the Flinders. Attempting to find a way through the salt lakes that he thought barred the path to the north, he climbed Mount Serle; this high range was the western heights of the Gammons. The next explorer to reach the area was the Surveyor General, Edward Charles Frome, on his second expedition up the eastern side of the Flinders three years later. After finding his route to the east blocked by the lake which would bear his name, he headed for the highest point in the ranges he could see, which he thought was Eyre's Mount Serle: however, his paintings show it to be Mount McKinlay.
A private surveyor, J. M. Painter, was employed in a survey of the area in 1857, his party climbed Gammon Hill and Mount McKinlay, but didn't penetrate to the peaks of the central range or plateau. One of several survey cairns built on a line they surveyed between Mount Rowe and Arcoona Bluff on the western edge of the ranges has been restored and can be visited today; the area has a colourful history of pastoral settlement dating from the turn of the century: the now-restored holiday cottage Grindell's Hut in Illinawortina Pound is named after John Grindell, who ran a small cattle station in the pound in the early part of the twentieth century. Grindell had a difficult relationship with his son-in-law George Snell, who ran the neighbouring Yankaninna station, suspecting him of rustling cattle; when Snell disappeared in August 1918, a search party found remains at a campfire in the ranges, Grindell was arrested and charged with Snell's murder. Despite the evidence being flimsy, Grindell was convicted at Port Augusta in December and sentenced to death, though it was commuted to life imprisonment.
He was released from prison in 1928, dying two years at the age of 77. A restored building at the site of his old hut is now rented out as a holiday cottage; the bushman R. M. Williams is reputed to have learnt everything he knew about boot-making and leather from another man he met while camped in Italowie Gap at the southern end of the ranges; the ranges were explored more in the first half of the 20th century: the Greenwood family, pastoralists in the area, had explored the edges in the twenties and thirties, discovering Fern Chasm, but it was not until expeditions by Warren Bonython and others in the late 1940s that the Plateau and main central
Arkaroola is the common name for the Arkaroola Wilderness Sanctuary, a wildlife sanctuary situated on 610 square kilometres of freehold and pastoral lease land in South Australia. It is located 700 kilometres north of the Adelaide city centre in the Northern Flinders Ranges, adjacent to the Vulkathunha-Gammon Ranges National Park and the Mawson Plateau; the most common way to get there is by car, but air travel can be chartered from Parafield Airport, Adelaide Airport or Aldinga Airfield. It was used as a location set the 2002 film The Tracker; the area's first people are the Adnyamathanha. One of their dreamtime or creation stories says that Arkaroo, a mythical monster, drank Lake Frome dry, he crawled up into the mountains. When he urinated he created the waterholes, his movement over the land created Arkaroola Creek. The first Anglo-Europeans to visit the area was explorer Edward Eyre in 1840 and the surveyor George Goyder in 1857. There was a small failed settlement nearby, at the Yudnamutana copper mine, from 1860 to 1863.
The drought of 1863 drove the miners away. Settlement didn't occur again until 1903, when sapphires were discovered. By 1910 a copper smelter was built at Yudnamutana and uranium was discovered nearby by Douglas Mawson, famous Antarctic explorer; the land was always marginal and projects failed quickly. Uranium exploration persisted sporadically and led to the development of good roads by optimistic companies; the Arkaroola property was fenced by 1935 and a process of eradication of pests started. The land was covered with camels. There was a failed health project in 1948; the Arkaroola Wilderness Sanctuary was established by geologist Reg Sprigg in 1968 after he purchased the pastoral lease. He had been involved in surveys in the area before that, he purchased the 610 square kilometres pastoral lease and began the conversion to a wildlife sanctuary. In 1979 he was a trustee of the World Wildlife Fund due to his work in the protection of the yellow-footed rock-wallaby. In July 2011 South Australian Premier Mike Rann announced a ban on mining in Arkaroola.
This was followed in October 2011 by special purpose legislation prohibiting mining, mining exploration and grazing in the ranges. The South Australian government has moved to nominate the Arkaroola area for listing on the National Heritage list, to secure its nomination for World Heritage listing. Arkaroola was listed on the South Australian Heritage Register on 27 July 2012; until mid-2011, Arkaroola was under threat from uranium mining. In 2008, Marathon was found guilty of illegally dumping radioactive waste in a variety of locations throughout the Arkaroola Wilderness Sanctuary, were ordered to suspend drilling operations. In late 2010, the government renewed the company's mineral exploration license, allowing it to resume exploratory drilling within the protected area, a decision which resulted in public outcry. A poll taken in February 2011 showed that 72 per cent of South Australians, 79 per cent of Labor voters, were opposed to mining in Arkaroola. Following unprecedented public pressure, the South Australian government announced on 22 July 2011 that mining would be banned forever in Arkaroola, with the aim of national and World Heritage listing.
Mining companies have since threatened legal action against the government. Protection of Arkaroola from mining, including Mount Gee and the Mount Painter inlier, is provided by the Arkaroola Protection Act 2012, which created the Arkaroola Protection Area. Arkaroola is part of the 1,890 square kilometres Gammon Ranges and Arkaroola Important Bird Area, identified as such by BirdLife International because it supports a population of the restricted-range short-tailed grasswren as well as populations of the pied honeyeater, chirruping wedgebill and cinnamon quail-thrush. There are self-drive and organised tour tracks for 2-wheel drives and 4-wheel drives, ranging from beginner to advanced in difficulty; the Echo Camp Backtrack self-drive track leads through some wonderful country and over the hills and down onto the plains east of the Flinders Ranges. This joins another track back to Arkaroola via Claude’s Pass, Stubb’s Waterhole, Bararranna Gorge, Welcome Pound and back to the main road to the Arkaroola Village.
Organised tours provide trips along the ridge top track with three lookouts that end at Siller's Lookout, providing a view across the plains towards Lake Frome and the Beverley Uranium Mine. Siller's Lookout is named after Bill Siller MBE, whose uranium exploration companies constructed the Ridge Top Tour track in the late 1960s. Beverley Uranium Mine discovered by Bill Siller's companies, is named after his wife, Beverley; the track was put in by an expatriate Canadian. There are a number of walking trails available and self-guided, some are marked and described by the Royal Geographical Society of Australia. Spriggina Trail Bararranna Gorge Walk Acacia Ridge Surveyor's Cairn Griselda Hill Mawson Valley Trail Arkaroola Waterhole Oppaminda Trail Coloured leaflets about some of these trails at Arkaroola and throughout the Flinders Ranges are available for download from the Walking Trails Support Group. Arkaroola has two 14-inch telescopes. Weather in the area is fine providing clear skies. There is little light pollution, due to the remote location and active control of the local lighting.
Paralana geothermal springs
In physical geography, a dune is a hill of loose sand built by aeolian processes or the flow of water. Dunes occur in different sizes, formed by interaction with the flow of air or water. Most kinds of dunes are longer on the stoss side, where the sand is pushed up the dune, have a shorter "slip face" in the lee side; the valley or trough between dunes is called a slack. A "dune field" or erg is an area covered by extensive dunes. Dunes occur along some coasts; some coastal areas have one or more sets of dunes running parallel to the shoreline directly inland from the beach. In most cases, the dunes are important in protecting the land against potential ravages by storm waves from the sea. Although the most distributed dunes are those associated with coastal regions, the largest complexes of dunes are found inland in dry regions and associated with ancient lake or sea beds. Dunes can form under the action of water flow, on sand or gravel beds of rivers and the sea-bed; the modern word "dune" came into English from French c.
1790, which in turn came from Middle Dutch dūne. Dunes are made of sand-sized particles, may consist of quartz, calcium carbonate, gypsum, or other materials; the upwind/upstream/upcurrent side of the dune is called the stoss side. Sand is pushed or bounces up the stoss side, slides down the lee side. A side of a dune that the sand has slid down is called a slip face; the Bagnold formula gives the speed. Five basic dune types are recognized: crescentic, star and parabolic. Dune areas may occur in three forms: simple and complex. Barchan dunes are crescent-shaped mounds which are wider than they are long; the lee-side slipfaces are on the concave sides of the dunes. These dunes form under winds that blow from one direction, they form separate crescents. When the sand supply is greater, they may merge into barchanoid ridges, transverse dunes; some types of crescentic dunes move more over desert surfaces than any other type of dune. A group of dunes moved more than 100 metres per year between 1954 and 1959 in China's Ningxia Province, similar speeds have been recorded in the Western Desert of Egypt.
The largest crescentic dunes on Earth, with mean crest-to-crest widths of more than three kilometres, are in China's Taklamakan Desert. See lunettes and parabolic dues, for dunes similar to crescent-shaped ones. Abundant barchan dunes may merge into barchanoid ridges, which grade into linear transverse dunes, so called because they lie transverse, or across, the wind direction, with the wind blowing perpendicular to the ridge crest. Seif dunes are linear dunes with two slip faces; the two slip faces make them sharp-crested. They are called seif dunes after the Arabic word for "sword", they may be more than 160 kilometres long, thus visible in satellite images. Seif dunes are associated with bidirectional winds; the long axes and ridges of these dunes extend along the resultant direction of sand movement. Some linear dunes merge to form Y-shaped compound dunes. Formation is debated. Bagnold, in The Physics of Blown Sand and Desert Dunes, suggested that some seif dunes form when a barchan dune moves into a bidirectional wind regime, one arm or wing of the crescent elongates.
Others suggest. In the sheltered troughs between developed seif dunes, barchans may be formed, because the wind is constrained to be unidirectional by the dunes. Seif dunes are common in the Sahara, they range up to 300 km in length. In the southern third of the Arabian Peninsula, a vast erg, called the Rub' al Khali or Empty Quarter, contains seif dunes that stretch for 200 km and reach heights of over 300 m. Linear loess hills known; these hills appear to have been formed during the last ice age under permafrost conditions dominated by sparse tundra vegetation. Radially symmetrical, star dunes are pyramidal sand mounds with slipfaces on three or more arms that radiate from the high center of the mound, they tend to accumulate in areas with multidirectional wind regimes. Star dunes grow upward rather than laterally, they dominate the Grand Erg Oriental of the Sahara. In other deserts, they occur around the margins of the sand seas near topographic barriers. In the southeast Badain Jaran Desert of China, the star dunes are up to 500 metres tall and may be the tallest dunes on Earth.
Oval or circular mounds that lack a slipface. Dome dunes occur at the far upwind margins of sand seas. Fixed crescentic dunes that form on the leeward margins of playas and river valleys in arid and semiarid regions in response to the direction of prevailing winds, are known as lunettes, source-bordering dunes and clay dunes, they may be composed of clay, sand, or gypsum, eroded from the basin floor or shore, transported up the concave side of the dune, deposited on the convex side. Examples in Australia are up to 6.5 km long, 1 km wide, up to 50 metres high. They occur in southern and West Africa, in parts of the western United States Texas. U-shaped mounds of sand with convex noses trailed by elongated arms are parabolic dunes; these dunes are formed from blowout dunes where the erosion
Mean sea level is an average level of the surface of one or more of Earth's oceans from which heights such as elevation may be measured. MSL is a type of vertical datum – a standardised geodetic datum –, used, for example, as a chart datum in cartography and marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to calibrate altitude and aircraft flight levels. A common and straightforward mean sea-level standard is the midpoint between a mean low and mean high tide at a particular location. Sea levels can be affected by many factors and are known to have varied over geological time scales; however 20th century and current millennium sea level rise is caused by global warming, careful measurement of variations in MSL can offer insights into ongoing climate change. The term above sea level refers to above mean sea level. Precise determination of a "mean sea level" is difficult to achieve because of the many factors that affect sea level. Instantaneous sea level varies quite a lot on several scales of space.
This is because the sea is in constant motion, affected by the tides, atmospheric pressure, local gravitational differences, salinity and so forth. The easiest way this may be calculated is by selecting a location and calculating the mean sea level at that point and use it as a datum. For example, a period of 19 years of hourly level observations may be averaged and used to determine the mean sea level at some measurement point. Still-water level or still-water sea level is the level of the sea with motions such as wind waves averaged out. MSL implies the SWL further averaged over a period of time such that changes due to, e.g. the tides have zero mean. Global MSL refers to a spatial average over the entire ocean. One measures the values of MSL in respect to the land. In the UK, the Ordnance Datum is the mean sea level measured at Newlyn in Cornwall between 1915 and 1921. Prior to 1921, the vertical datum was MSL at the Victoria Liverpool. Since the times of the Russian Empire, in Russia and other former its parts, now independent states, the sea level is measured from the zero level of Kronstadt Sea-Gauge.
In Hong Kong, "mPD" is a surveying term meaning "metres above Principal Datum" and refers to height of 1.230m below the average sea level. In France, the Marégraphe in Marseilles measures continuously the sea level since 1883 and offers the longest collapsed data about the sea level, it is used for main part of Africa as official sea level. As for Spain, the reference to measure heights below or above sea level is placed in Alicante. Elsewhere in Europe vertical elevation references are made to the Amsterdam Peil elevation, which dates back to the 1690s. Satellite altimeters have been making precise measurements of sea level since the launch of TOPEX/Poseidon in 1992. A joint mission of NASA and CNES, TOPEX/Poseidon was followed by Jason-1 in 2001 and the Ocean Surface Topography Mission on the Jason-2 satellite in 2008. Height above mean sea level is the elevation or altitude of an object, relative to the average sea level datum, it is used in aviation, where some heights are recorded and reported with respect to mean sea level, in the atmospheric sciences, land surveying.
An alternative is to base height measurements on an ellipsoid of the entire Earth, what systems such as GPS do. In aviation, the ellipsoid known as World Geodetic System 84 is used to define heights; the alternative is to use a geoid-based vertical datum such as NAVD88. When referring to geographic features such as mountains on a topographic map, variations in elevation are shown by contour lines; the elevation of a mountain denotes the highest point or summit and is illustrated as a small circle on a topographic map with the AMSL height shown in metres, feet or both. In the rare case that a location is below sea level, the elevation AMSL is negative. For one such case, see Amsterdam Airport Schiphol. To extend this definition far from the sea means comparing the local height of the mean sea surface with a "level" reference surface, or geodetic datum, called the geoid. In a state of rest or absence of external forces, the mean sea level would coincide with this geoid surface, being an equipotential surface of the Earth's gravitational field.
In reality, due to currents, air pressure variations and salinity variations, etc. this does not occur, not as a long-term average. The location-dependent, but persistent in time, separation between mean sea level and the geoid is referred to as ocean surface topography, it varies globally in a range of ± 2 m. Adjustments were made to sea-level measurements to take into account the effects of the 235 lunar month Metonic cycle and the 223-month eclipse cycle on the tides. Several terms are used to describe the changing relationships between sea level and dry land; when the term "relative" is used, it means change relative to a fixed point in the sediment pile. The term "eustatic" refers to global changes in sea level relative to a fixed point, such as the centre of the earth, for example as a result of melting ice-caps; the term "steric" refers to global changes in sea level due to thermal expansion and salinity variations. The term "isostatic" refers to changes in
The Strzelecki Desert is located in the Far North Region of South Australia, South West Queensland and western New South Wales. It is positioned in the northeast of the Lake Eyre Basin, north of the Flinders Ranges. Two other deserts occupy the Lake Eyre Basin -- the Simpson Desert; the desert covers 80,250 km2 making it the seventh largest desert in Australia. The Dingo Fence, Birdsville Track, the Strzelecki Track, the Diamantina River, Cooper Creek and the Strzelecki Creek all pass through the Desert; the desert is home to three wilderness areas. It was named after the Polish explorer Paweł Edmund Strzelecki by Charles Sturt, he was the first non-indigenous explorer in the area, followed by the ill-fated Burke and Wills expedition. Much of the desert is preserved within the Strzelecki Regional Reserve in South Australia. Parts of the eastern sections of the desert are protected by the Sturt National Park in New South Wales. A population of the endangered Dusky Hopping Mouse lives in the desert.
The Cobbler Sandhills near Lake Blanche is a section of the Strzelecki Desert where the dunes are replaced by small eroded knolls with vegetation on the top. This area provided great difficulty for early attempts to cross the desert by car, the name relates to the sheep which were the most difficult to shear, known as the "cobblers". Bore Track Deserts of Australia Strzelecki Innamincka.com: Aerial Video of the Strzelecki Desert