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50-457: The desert is 1,000 kilometres (620 miles) long, and 500 kilometres (310 miles) wide. Its surface elevation varies from 800 metres (2,600 ft) in the southwest to around sea level in the northeast. The terrain is covered with sand dunes with heights up to 250 metres (820 ft), interspersed with gravel and gypsum plains. The sand is reddish-orange due to the presence of feldspar . There are also brackish salt flats in some areas, such as

100-591: A US Air Force expedition crossed the Rub' al Khali from Dhahran , Saudi Arabia, to central Yemen and back in trucks to collect specimens for the Smithsonian Institution and to test desert survival procedures. In 1999, Jamie Clarke became the first Westerner to cross the Empty Quarter of Arabia in fifty years. His team of six, guided by three Bedouins , spent 40 days crossing the desert with

150-533: A caravan of 13 camels. On 25 February 2006, a scientific excursion organized by the Saudi Geological Survey began to explore the Empty Quarter. The expedition consisted of 89 environmentalists, geologists, and scientists from Saudi Arabia and abroad. Various types of fossilized creatures as well as meteorites were discovered in the desert. The expedition discovered 31 new plant species and plant varieties, as well as 24 species of birds that inhabit

200-510: A crossing through the Empty Quarter on foot from Salalah, Oman , to Liwa Oasis in the UAE Emirate of Abu Dhabi . The crossing was performed with permission from the governments of Oman and UAE. Dewan Ruler's Representative for Western Region, Emirate of Abu Dhabi recognized it as the world's first on-foot crossing of the Empty Quarter following the border of Oman and ending in UAE. In 2018,

250-434: A diameter of between 0.074 and 4.75 millimeters. By another definition, in terms of particle size as used by geologists , sand particles range in diameter from 0.0625 mm (or 1 ⁄ 16  mm) a volume of approximately 0.00012 cubic millimetres, to 2 mm, a volume of approximately 4.2 cubic millimetres, the difference in volumes being 34,688 measures difference. Any particle falling within this range of sizes

300-434: A documentary called " Sand Wars " about the impact of the lack of construction sand. It shows the ecological and economic effects of both legal and illegal trade in construction sand. To retrieve the sand, the method of hydraulic dredging is used. This works by pumping the top few meters of sand out of the water and filling it into a boat, which is then transported back to land for processing. All marine life mixed in with

350-610: A high olivine content. Many sands, especially those found extensively in Southern Europe , have iron impurities within the quartz crystals of the sand, giving a deep yellow color. Sand deposits in some areas contain garnets and other resistant minerals, including some small gemstones . Rocks erode or weather over a long period of time, mainly by water and wind, and their sediments are transported downstream. These sediments continue to break apart into smaller pieces until they become fine grains of sand. The type of rock

400-580: A number of Al Murrah tribespeople, along with several members from the Bani Hajer tribe, renounced their allegiance to Qatar and departed from the country. The two families were joined by the Ajman tribe, whom were known to harbor hostilities toward Qatar and regularly engage in skirmishes with its inhabitants. While the group was encamped in an area between Qatar and Oman , a regiment of 1,200 partisans composed of branches of Al Murrah and Bani Hajer loyal to

450-489: A result. People sometimes dig holes in the sand at beaches for recreational purposes, but if too deep they can result in serious injury or death in the event of a collapse. Manufactured sand (M sand) is sand made from rock by artificial processes, usually for construction purposes in cement or concrete. It differs from river sand by being more angular, and has somewhat different properties. In Dubai , United Arab Emirates , sand needed to construct infrastructure and create

500-483: A significant dredging industry, raising environmental concerns over fish depletion, landslides, and flooding. Countries such as China, Indonesia, Malaysia, and Cambodia ban sand exports, citing these issues as a major factor. It is estimated that the annual consumption of sand and gravel is 40 billion tons and sand is a US$ 70 billion global industry. With increasing use, more is expected to come from recycling and alternatives to sand. The global demand for sand in 2017

550-420: Is silica (silicon dioxide, or SiO 2 ), usually in the form of quartz . Calcium carbonate is the second most common type of sand. One such example of this is aragonite , which has been created over the past 500   million years by various forms of life, such as coral and shellfish . It is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years, as in

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600-508: Is called grus in geology or sharp sand in the building trade where it is preferred for concrete, and in gardening where it is used as a soil amendment to loosen clay soils. Sand that is transported long distances by water or wind will be rounded, with characteristic abrasion patterns on the grain surface. Desert sand is typically rounded. People who collect sand as a hobby are known as arenophiles . Organisms that thrive in sandy environments are psammophiles. Only some sands are suitable for

650-427: Is defined by its grain size. Sand grains are smaller than gravel and coarser than silt . Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non- tropical coastal settings

700-433: Is termed a sand grain . Sand grains are between gravel (with particles ranging from 2 mm up to 64 mm by the latter system, and from 4.75 mm up to 75 mm in the former) and silt (particles smaller than 0.0625 mm down to 0.004 mm). The size specification between sand and gravel has remained constant for more than a century, but particle diameters as small as 0.02 mm were considered sand under

750-474: Is the most common mineral resistant to weathering . The composition of mineral sand is highly variable, depending on the local rock sources and conditions. The bright white sands found in tropical and subtropical coastal settings are eroded limestone and may contain coral and shell fragments in addition to other organic or organically derived fragmental material, suggesting that sand formation depends on living organisms, too. The gypsum sand dunes of

800-738: The Albert Atterberg standard in use during the early 20th century. The grains of sand in Archimedes ' The Sand Reckoner written around 240 BCE, were 0.02 mm in diameter. A 1938 specification of the United States Department of Agriculture was 0.05 mm. A 1953 engineering standard published by the American Association of State Highway and Transportation Officials set the minimum sand size at 0.074 mm. Sand feels gritty when rubbed between

850-748: The Caribbean . Somewhat more rarely, sand may be composed of calcium sulfate , such as gypsum and selenite , as is found in places such as White Sands National Park and Salt Plains National Wildlife Refuge in the U.S. Sand is a non-renewable resource over human timescales, and sand suitable for making concrete is in high demand. Desert sand, although plentiful, is not suitable for concrete. Fifty billion tons of beach sand and fossil sand are used each year for construction. The exact definition of sand varies. The scientific Unified Soil Classification System used in engineering and geology corresponds to US Standard Sieves, and defines sand as particles with

900-579: The Dubai Islands exceeds local supplies, requiring sand from Australia . The artificial islands required more than 835 million tonnes of sand, at a cost greater than $ 26 billion USD. [REDACTED] Earth Sciences portal Al Murrah The Al Murrah ( Arabic : آل مرة ) (singular 'Al Marri') is an Arab tribe descended from the well-known Banu Yam tribe. They mainly reside in countries such as Qatar , Saudi Arabia , United Arab Emirates , Kuwait and Bahrain . Historically, Al Murrah

950-514: The Krumbein phi scale , where size is Φ = -log 2 D; D being the particle size in mm. On this scale, for sand the value of Φ varies from −1 to +4, with the divisions between sub-categories at whole numbers. The most common constituent of sand, in inland continental settings and non-tropical coastal settings, is silica (silicon dioxide, or SiO 2 ), usually in the form of quartz , which, because of its chemical inertness and considerable hardness,

1000-470: The Tuwaiq Escarpment . Evidence suggests that the lakes were home to a variety of flora and fauna. Fossil remains indicate the presence of several animal species, such as hippopotamus , water buffalo , and long-horned cattle . The lakes also contained small snails, ostracods , and when conditions were suitable, freshwater clams . Deposits of calcium carbonate and opal phytoliths indicate

1050-516: The Umm al Samim area on the desert's eastern edge. Ali Al-Naimi reports that the sand dunes do not drift. He goes on to say, Sand blows off the surface, of course, but the essential shape of the dunes remains intact, probably due to the moisture leaching up into the base of the dunes from the surrounding sabkhas . Along the middle length of the desert, there are several raised, hardened areas of calcium carbonate , gypsum, marl , or clay that were once

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1100-687: The White Sands National Park in New Mexico are famous for their bright, white color. Arkose is a sand or sandstone with considerable feldspar content, derived from weathering and erosion of a (usually nearby) granitic rock outcrop. Some sands contain magnetite , chlorite , glauconite , or gypsum . Sands rich in magnetite are dark to black in color, as are sands derived from volcanic basalts and obsidian . Chlorite - glauconite bearing sands are typically green in color, as are sands derived from basaltic lava with

1150-449: The caravan trails leading across the Rub' al Khali so difficult, the caravans of the frankincense trade crossed now virtually impassable stretches of land, until about 300 AD. It has been suggested that Ubar or Iram , a lost city , region or people, depended on such trade. The archaeological remains of Iram include a fortification/administration building, walls and bases of circular pillars. The traces of camel tracks, unidentifiable on

1200-688: The Empty Quarter, was completed in September 2021. Measuring between 700 and 800 kilometres (430 and 500 miles), it extends from Ibri in Oman to Al-Ahsa in eastern Saudi Arabia . A 160 km (99 miles) stretch of the road is on the Omani side and 580 km (360 miles) on the Saudi side. The road also goes through the archaeological sites of Bat, Al-Khutm and Al-Ayn in Oman. Desertification has increased through recent millennia. Before desertification made

1250-570: The Empty Quarter. As an ecoregion , the Rub' al Khali falls within the Arabian Desert and East Saharo-Arabian xeric shrublands . The Asiatic cheetah , once widespread in Saudi Arabia, is extirpated. The Shaybah oil field was discovered in 1968. South Ghawar , discovered in 1948, is the largest oil field in the world and extends southward into the northernmost parts of the Empty Quarter. A road between Oman and Saudi Arabia, through

1300-695: The Rub' al Khali from the South (the Saudi-Omani border) to the North (the Saudi-UAE border) on foot. This was the first known crossing within Saudi Arabia from south-north on foot through the highest sand dunes of the Rub Al' Khali. The pair crossed 300 km (190 mi) in nine days 12 hours and 59 minutes. In 2020, Italian extreme desert explorer Max Calderan completed a Rub' al Khali exploration on foot for

1350-487: The Sahara is sand dunes, while 70% is bare rock. The wind is responsible for creating these different environments and shaping the sand to be round and smooth. These properties make desert sand unusable for construction. Beach sand is also formed by erosion. Over thousands of years, rocks are eroded near the shoreline from the constant motion of waves and the sediments build up. Weathering and river deposition also accelerate

1400-685: The United States. The expedition started from Al Hashman in the Dohafar Governate of Oman crossing through Burkana, Maqshin, and Al Sahma in Al Wusta Region continuing through Abu Al Tabool, Um Al Sameem ending at Ibri fort in the Al Dhahira region of Oman. The total distance walked by the team was 758 km (471 mi) in 28 days, ending the expedition on 18 January 2019. In 2018, Deidre O'Leary and Kyle Knight crossed

1450-416: The area's water resources and oil production centers. The first documented journeys by non-resident explorers were made by British explorers Bertram Thomas and St John Philby in the early 1930s. Between 1946 and 1950, Wilfred Thesiger crossed the area several times and mapped large parts of the Empty Quarter including the mountains of Oman, as described in his 1959 book Arabian Sands . In June 1950,

1500-441: The construction industry, for example for making concrete . Grains of desert sand are rounded by being blown in the wind, and for this reason do not produce solid concrete, unlike the rough sand from the sea. Because of the growth of population and of cities and the consequent construction activity there is a huge demand for these special kinds of sand, and natural sources are running low. In 2012 French director Denis Delestrac made

1550-438: The extracted sand is killed and the ecosystem can continue to suffer for years after the mining is complete. Not only does this affect marine life, but also the local fishing industries because of the loss of life, and communities living close to the water's edge. When sand is taken out of the water it increases the risk of landslides, which can lead to loss of agricultural land and/or damage to dwellings. Sand's many uses require

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1600-597: The fingers. Silt , by comparison, feels like flour . ISO 14688 grades sands as fine, medium, and coarse with ranges 0.063 mm to 0.2 mm to 0.63 mm to 2.0 mm. In the United States, sand is commonly divided into five sub-categories based on size: very fine sand ( 1 ⁄ 16 – 1 ⁄ 8  mm diameter), fine sand ( 1 ⁄ 8  mm – 1 ⁄ 4  mm), medium sand ( 1 ⁄ 4  mm – 1 ⁄ 2  mm), coarse sand ( 1 ⁄ 2  mm – 1 mm), and very coarse sand (1 mm – 2 mm). These sizes are based on

1650-530: The first all-female walking expedition named "her faces of change" led by Briton Janey McGill who was accompanied by the first Omani women in modern times to walk the Oman Empty Quarter, Baida Al Zadjali and Atheer Al Sabri, set off on 22 December 2018 after receiving formal approval from the government of Oman. The team was supported by two cars for supplies driven by Tariq Al Zadjali (Omani) and Mark Vause-Jones (British) and filmmaker Matthew Milan from

1700-595: The first time ever from west to east. He crossed 1,100 km (680 mi) in 18 days, crossing the widest area of Rub' al Khali. In 2023, an Austrian-German expedition completed a southwest-to-northeast crossing of the Rub-al-Khali region on the Saudi Arabian side. The route was planned by Austrian Thomas Brandl-Ruttner, leading a team of eight experts in navigation, expedition logistics, and engineering. The team included geo-archaeologist Rudolf Dellmour, who

1750-705: The ground, appear in satellite images. Today the inhabitants of the Empty Quarter are members of various local tribes: for example, the Al Murrah tribe has the largest area mainly based between Al-Ahsa and Najran . The Banu Yam and Banu Hamdan (in Yemen and the Najran region of southern Saudi Arabia), and the Bani Yas (in the United Arab Emirates). A few road links connect these tribal settlements to

1800-495: The journey and pulled a specially designed cart that housed all the supplies necessary for the entire expedition. In 2013, British adventurer Alistair Humphreys released his first documentary film, Into the Empty Quarter, documenting his walk through the Empty Quarter desert with Leon McCarron. In 2013, from 18 February to 28 March, South Korean explorer Young-Ho Nam led a team (Agustin Arroyo Bezanilla, Si-Woo Lee) on

1850-399: The new Emir of Qatar, Sheikh Hamad Al Thani , but failed. In February 2000, 19 of the alleged perpetrators had been sentenced to death, 33 were sentenced to life in prison, and the rest were acquitted. However, none of those sentenced to death were executed. In 2017 Qatar revoked the citizenship of the sheikh and 54 tribespeople. Al Murrah are friendly to UAE and Saudi Arabia and negative to

1900-590: The presence of plants and algae. There is also evidence of human activity dating from 3,000 to 2,000 years ago, including chipped flint tools, but no actual human remains have been found. The region is classified as " hyper-arid ", with annual precipitation generally less than 50 millimetres (2.0 in), and daily mean relative humidity of about 52% in January and 15% in June–July. Fauna includes arachnids (e.g. scorpions ) and rodents , while plants live throughout

1950-437: The process of creating a beach, along with marine animals interacting with rocks, such as eating the algae off of them. Once there is a sufficient amount of sand, the beach acts as a barrier to keep the land from eroding any further. This sand is ideal for construction as it is angular and of various sizes. Marine sand (or ocean sand) comes from sediments transported into the ocean and the erosion of ocean rocks. The thickness of

2000-461: The rate the sand can replenish, making it a non-renewable resource. Sand dunes are a consequence of dry conditions or wind deposition. The Sahara Desert is very dry because of its geographic location and proximity to the equator . It is known for its vast sand dunes, which exist mainly due to a lack of vegetation and water. Over time, wind blows away fine particles, such as clay and dead organic matter, leaving only sand and larger rocks. Only 15% of

2050-552: The region, which fascinated scientists as to how they have survived under the harsh conditions of the Empty Quarter. In February 2013, a South African team including Alex Harris, Marco Broccardo, and David Joyce became the first people to cross the border close to Oman of the Empty Quarter unsupported and on foot, in a journey which started in Salalah and lasted 40 days, ending in Dubai . The team only made use of three water stops along

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2100-460: The sand because they do not have as much time to dissolve away. The term for sand formed by weathering is "epiclastic." Sand from rivers are collected either from the river itself or its flood plain and accounts for the majority of the sand used in the construction industry. Because of this, many small rivers have been depleted, causing environmental concern and economic losses to adjacent land. The rate of sand mining in such areas greatly outweighs

2150-480: The sand layer varies, however it is common to have more sand closer to land; this type of sand is ideal for construction and is a very valuable commodity. Europe is the main miners of marine sand, which greatly hurts ecosystems and local fisheries. The study of individual grains can reveal much historical information as to the origin and kind of transport of the grain. Quartz sand that is recently weathered from granite or gneiss quartz crystals will be angular. It

2200-411: The sediment originated from and the intensity of the environment give different compositions of sand. The most common rock to form sand is granite , where the feldspar minerals dissolve faster than the quartz , causing the rock to break apart into small pieces. In high energy environments rocks break apart much faster than in more calm settings. In granite rocks this results in more feldspar minerals in

2250-402: The sheikh of Qatar engaged the group. Although the three tribes boasted a combined force of 2,000 men and outnumbered the opposition, they were inflicted with heavy losses. A majority of tribe members were strong supporters of Sheikh Khalifa Al Thani , the former Emir of Qatar who was deposed in 1995 in a coup by his son. Eight months after the coup, 119 Al Murrah members attempted to overthrow

2300-501: The site of shallow lakes. These lakes existed during periods from 6,000 to 5,000 years ago and 3,000 to 2,000 years ago. The lakes are thought to have formed as a result of "cataclysmic rainfall" similar to present-day monsoon rains and most probably lasted for only a few years. However, lakes in the Mundafen area in the southwest of the Rub' al Khali show evidence of such lakes lasting longer, up to 800 years, from increased runoff from

2350-493: The user to wear respiratory protection to avoid breathing the resulting fine silica dust . Safety data sheets for silica sand state that "excessive inhalation of crystalline silica is a serious health concern." In areas of high pore water pressure , sand and salt water can form quicksand , which is a colloid hydrogel that behaves like a liquid. Quicksand produces a considerable barrier to escape for creatures caught within, who often die from exposure (not from submersion) as

2400-635: Was 9.55 billion tons as part of a $ 99.5 billion industry. In April 2022, the United Nations Environment Programme (UNEP) published a report stating that 50 billion tons of sand and gravel were being used every year. The report made 10 recommendations, including a ban on beach extraction, to avert a crisis, and move toward a circular economy for the two resources. While sand is generally non-toxic, sand-using activities such as sandblasting require precautions. Bags of silica sand used for sandblasting now carry labels warning

2450-523: Was a tribe of camel -herding nomads, who controlled and travelled through a vast area of the Arabian Peninsula . Seven clans make up the Saudi branch of the Al Murrah. Travelling as much as 3,000 kilometres (1,900 mi) each year, the tribe comprises approximately 15,000 individuals. Historically, the Al Murrah tribe made up a large proportion of Qatar's ethnic population. In 1885,

2500-437: Was responsible for scientific documentation. Covering a 1,500-kilometer route through largely unexplored terrain, the team gathered and documented new geological and archaeological findings. Locations that had previously only been studied via satellite imagery were explored on site for the first time. Sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but

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