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52-756: The Huqf Supergroup is exposed in the Jabal Akhdar of the Al Hajar Mountains , and in the deformed and metamorphosed domal culmination of the Saih Hatat. Source rocks of the Neoproterozoic to Cambrian Huqf Supergroup are associated with most of the South Oman oils. However, the geochemical similarity of the organic matter across the Huqf sequence has impeded to assign oils to Huqf intervals. Huqf Supergroup preserves

104-566: A subspecies of Wadi Kharrar rock gecko ( Pristurus gallagheri ) are found only in Oman while Musandam leaf-toed gecko ( Asaccus caudivolvulus ), Gallagher's leaf-toed gecko ( Asaccus gallagheri ), Oman rock gecko ( Pristurus celerrimus ), Jayakar lizard ( Omanosaura jayakari ) and Oman blue-tailed lizard ( Omanosaura cyanura ) are found only in the Hajar. The endangered Arabian leopard ( Panthera pardus nimr ) had been recorded here, particularly in

156-476: A SW-dipping subduction zone. The two culminations are separated by the Semail Gap. This is a prominent linear structure, trending NNE—SSW. However, it is still debated as to what this structure is. Different geologists claim that it is a left-lateral (sinistral) strike-slip fault , a normal fault , a lateral ramp, a monocline due to a blind thrust , or a fault with multiple phases of deformation. There

208-472: A complete sequence of Cryogenian , Ediacaran, and early Cambrian strata, becoming the group a reference in Earth history . This article about the geography of Oman is a stub . You can help Misplaced Pages by expanding it . Al Hajar Mountains The Hajar Mountains ( Arabic : جِبَال ٱلْحَجَر , romanized :  Jibāl al-Ḥajar , The Rocky Mountains or The Stone Mountains ) are one of

260-403: A molecular dynamics technique. The accuracy of the model at room temperature and atmospheric pressure was checked against crystal structural data, with maximum deviations of c. 4% for the haloapatites and 8% for hydroxyapatite. High-pressure simulation runs, in the range 0.5–75 kbar, were performed in order to estimate the isothermal compressibility coefficient of those compounds. The deformation of

312-479: A much shallower depth to basement in the Hajar Mountains and a deeper depth to basement in the foreland basin to the west. This has implications on economic geology such as the mining for precious minerals and the extraction of oil and gas. The late Cretaceous obduction event created the proto-Hajar Mountains. However, this topography subsided and shallow marine sedimentation covered the region, beginning in

364-550: A number of endemic species. The vegetation changes with altitude, the mountains are covered with shrubland at lower elevations, growing richer and then becoming woodland, including wild olive and fig trees between 3,630 and 8,250 ft (1,110 and 2,510 metres), and then higher still there are junipers . Fruit trees such as pomegranate and apricot are grown in the cooler valleys and in places there are rocky outcrops with little vegetation. The flora shows similarities with mountain areas of nearby Iran , as well as with areas along

416-447: A series of nappes ( allochthonous rocks) that were transported from the northeast to the southwest horizontally for more than 300 km (190 mi). This was a major tectonic event during the late Cretaceous . This process is called obduction , where Permian to middle Cretaceous continental slope-rise (shallow to deep marine) sedimentary rocks and late Cretaceous oceanic crust ( Semail ophiolite ) were thrust (obducted) above

468-685: Is also well established from noble gas diffusion studies for use in determining thermal histories and other, less typical applications such as paleo-wildfire dating. The primary use of apatite is as a source of phosphate in the manufacture of fertilizer and in other industrial uses. It is occasionally used as a gemstone. Ground apatite was used as a pigment for the Terracotta Army of 3rd-century BCE China, and in Qing Dynasty enamel for metalware . During digestion of apatite with sulfuric acid to make phosphoric acid , hydrogen fluoride

520-400: Is concern in the geological community that with the development of infrastructure these rocks that contain a great deal of information will be excavated and destroyed. The central section of the Hajar is the highest and wildest terrain in the country. Jabal Shams is the highest of the range, followed by Jebel Akhdar . The latter and the smaller Jebel Nakhl range are bounded on the east by

572-578: Is named as "the stone" or "the rock". The Hajar Mountains extend for 700 kilometres (430 miles) through the UAE and Oman. They are located on the north-east corner of the Arabian Plate , reaching from the Musandam Peninsula through to the east coast of Oman . The range is about 100 km (62 mi) wide, with Jabal Shams being the highest peak at 3,009 m (9,872 ft) in the central region of

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624-454: Is preferable to traditional rare-earth ores such as monazite , as apatite is not very radioactive and does not pose an environmental hazard in mine tailings . However, apatite often contains uranium and its equally radioactive decay-chain nuclides. The town of Apatity in the Arctic North of Russia was named for its mining operations for these ores. Apatite is an ore mineral at

676-436: Is produced as a byproduct from any fluorapatite content. This byproduct is a minor industrial source of hydrofluoric acid . Apatite is also occasionally a source of uranium and vanadium , present as trace elements in the mineral. Fluoro-chloro apatite forms the basis of the now obsolete Halophosphor fluorescent tube phosphor system. Dopant elements of manganese and antimony, at less than one mole-percent — in place of

728-478: Is some debate over whether the topography of the Hajar Mountains is due to thin or thick-skinned tectonics (if basement rocks were faulted during collision to create uplift due to thrust faults). Recent Bouguer gravity and magnetotelluric geophysical data suggest deep basement faults that have been activated as thrust faults during the collisional event that obducted the Semail Ophiolite. This has resulted in

780-500: Is the defining mineral for 5 on the Mohs scale . It can be distinguished in the field from beryl and tourmaline by its relative softness. It is often fluorescent under ultraviolet light . Apatite is one of a few minerals produced and used by biological micro-environmental systems. Hydroxyapatite, also known as hydroxylapatite, is the major component of tooth enamel and bone mineral . A relatively rare form of apatite in which most of

832-718: Is the prototype of a class of chemically, stoichometrically or structurally similar minerals, biological materials, and synthetic chemicals. Those most similar to apatite are also known as apatites, such as lead apatite ( pyromorphite ) and barium apatite ( alforsite ). More chemically dissimilar minerals of the apatite supergroup include belovites , britholites , ellestadites and hedyphanes . Apatites have been investigated for their potential use as pigments (copper-doped alkaline earth apatites), as phosphors and for absorbing and immobilising toxic heavy metals. In apatite minerals strontium , barium and lead can be substituted for calcium; arsenate and vanadate for phosphate; and

884-500: Is usually restricted to pegmatites , gneiss derived from sediments rich in carbonate minerals , skarns , or marble . Apatite is also found in clastic sedimentary rock as grains eroded out of the source rock. Phosphorite is a phosphate-rich sedimentary rock containing as much as 80% apatite, which is present as cryptocrystalline masses referred to as collophane . Economic quantities of apatite are also sometimes found in nepheline syenite or in carbonatites . Apatite

936-464: Is written as Ca 10 ( PO 4 ) 6 (OH,F,Cl) 2 , and the crystal unit cell formulae of the individual minerals are written as Ca 10 (PO 4 ) 6 (OH) 2 , Ca 10 (PO 4 ) 6 F 2 and Ca 10 (PO 4 ) 6 Cl 2 . The mineral was named apatite by the German geologist Abraham Gottlob Werner in 1786, although the specific mineral he had described was reclassified as fluorapatite in 1860 by

988-462: The Apollo program contain traces of apatite. Following new insights about the presence of water in the moon, re-analysis of these samples in 2010 revealed water trapped in the mineral as hydroxyl , leading to estimates of water on the lunar surface at a rate of at least 64 parts per billion – 100 times greater than previous estimates – and as high as 5 parts per million. If

1040-582: The Eocene Epoch around 45-40 Ma. This episode saw the reactivation of cretaceous thrust faults and the development of long and short wavelength folding of Paleocene marine sediments that infilled previous foredeep accommodation. Low temperature thermodchronometry of apatite grains has given ages to this deformation and subsequent exhumation of the mountain belt. Exhumation occurred in two states, first between 45 and 40 Ma and again from 20 to 15 Ma. This later unroofing could also be related to tectonic uplift in

1092-645: The Hoidas Lake rare-earth project. The standard enthalpies of formation in the crystalline state of hydroxyapatite, chlorapatite and a preliminary value for bromapatite, have been determined by reaction-solution calorimetry . Speculations on the existence of a possible fifth member of the calcium apatites family, iodoapatite, have been drawn from energetic considerations. Structural and thermodynamic properties of crystal hexagonal calcium apatites, Ca 10 (PO 4 ) 6 (X) 2 (X= OH, F, Cl, Br), have been investigated using an all-atom Born-Huggins-Mayer potential by

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1144-661: The Makran subduction zone . The Hajar Mountains are the product of polyphase mountain building . Uplift and deformation of the Arabian passive margin began during the late cretaceous as the African-Arabian Plate began to subduct under the South Tethyan Oceanic Plate imitated at an intra oceanic subduction zone . This initiation may have been the result of plate rotation due to the breakup of Gondwana . Similar to

1196-525: The Paleocene . Paleocene to Eocene sedimentary rocks are found at 2,200 m (7,200 ft) above sea level within the Hajar, and are folded . This indicates that the present day topography formed after the late Eocene . The exact timing is debated, and various interpretations indicate the topography formed anywhere between the late Eocene through to the Miocene . The driving forces that formed

1248-658: The Red Sea in the Horn of Africa . For example, the tree Ceratonia oreothauma is found here and also in Somalia . A number of birds are found in the mountains including Egyptian and lappet-faced vultures ( Torgos tracheliotus ). Mammals include mountain gazelles ( Gazella gazella ) and the Arabian tahr ( Arabitragus jayakari ). Other endemic species include a number of geckos and lizards: Asaccus montanus , Asaccus platyrhynchus and

1300-537: The mantle , and then exhumed back to the surface. This exhumation event created possibly the largest megasheath fold on Earth, the Wadi Mayh megasheath fold. The common view is that these eclogites were originally basic volcanic rocks within the leading edge of the continental crust of the Arabian Plate . This leading edge was then subducted by a NE-dipping subduction zone . However, some geologists have interpreted that these eclogites were subducted through

1352-492: The outlier of Jebel Hafeet , which measures 1,100–1,400 m (3,600–4,600 ft) in height. Due to its proximity to the main range, it may be treated as one of the Hajar Mountains, sensu lato . This mountain has ridges which stretch northwards to the city of Al Ain. The northernmost mountains of the Hajar range are found on the Musandam Peninsula. For this reason, the phrase Ru'us al-Jibal ("Heads of

1404-443: The teeth of fluoride ions for hydroxyl groups in apatite. Similarly, toothpaste typically contains a source of fluoride anions (e.g. sodium fluoride, sodium monofluorophosphate ). Too much fluoride results in dental fluorosis and/or skeletal fluorosis . Fission tracks in apatite are commonly used to determine the thermal histories of orogenic belts and of sediments in sedimentary basins . (U-Th)/He dating of apatite

1456-540: The Eastern Hajar, for the protection of Arabian tahr and mountain gazelle. For visitors, there is a road into the mountains from the town of Birkat al-Mawz (on the road to Nizwa from Muscat) and a walking route through Wadi al-Muaydin to the Saiq Plateau. There are 11 marked trails/routes of varying intensity (between Grade 1 to 3) and duration (between 1.5 hours to 18 hours) published by Ministry of Tourism, Oman along

1508-552: The German mineralogist Karl Friedrich August Rammelsberg . Apatite is often mistaken for other minerals. This tendency is reflected in the mineral's name, which is derived from the Greek word ἀπατάω (apatáō), which means to deceive . Apatite is very common as an accessory mineral in igneous and metamorphic rocks, where it is the most common phosphate mineral . However, occurrences are usually as small grains which are often visible only in thin section . Coarsely crystalline apatite

1560-477: The Hajar is also debated. Many geologists relate the Zagros Collision as the reason for the uplift forming the mountains, as currently the Musandam Peninsula (northwest corner of the mountain range) is uplifting due to this collision. However, Jabal Shams , the highest peak of the central mountains is over 300 km (190 mi) away from this zone. In addition, there is no major seismicity within

1612-421: The Hajar range. Some areas are inaccessible, and requires special equipment, as shown in a Steve Backshall TV documentary. Other notes: Apatite Apatite is a group of phosphate minerals , usually hydroxyapatite , fluorapatite and chlorapatite, with high concentrations of OH , F and Cl ion , respectively, in the crystal . The formula of the admixture of the three most common endmembers

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1664-635: The Hajar, the Semail ophiolite is still intact. Oman also has one of the best exposed mega-sheath folds ever discovered, the Wadi Mayh sheath fold. Additionally, the relatively small outcrop of eclogite is important. Eclogite is rare on the Earths surface, as it is a rock that forms at high pressures deep within the crust or mantle . Geologists can learn about what is occurring in the Earths interior and tectonic processes from these rocks. There are also various fossil localities in Oman that need to be protected. There

1716-573: The Mountains") is applied to them, or the peninsula itself. Despite being physically part of the western Hajar, they differ in geology and hydrology to the rest of the range. The highest point in the UAE is located at Jebel Jais near Ras Al Khaimah , which measures 1,911 m (6,270 ft) from sea level, but since the summit is on the Omani side, Jabal ar Rahrah , measuring over 1,691 m (1.051 miles), has

1768-451: The OH groups are absent and containing many carbonate and acid phosphate substitutions is a large component of bone material. Fluorapatite (or fluoroapatite) is more resistant to acid attack than is hydroxyapatite; in the mid-20th century, it was discovered that communities whose water supply naturally contained fluorine had lower rates of dental caries . Fluoridated water allows exchange in

1820-521: The Western Hajar ( Arabic : ٱلْحَجَر ٱلْغَرْبِي , romanized :  Al-Ḥajar Al-Gharbī ), also known as the " Oman proper ". Since Jabal Akhdar and mountains in its vicinity are west of the valley, they may be regarded as Western Hajar. In the region of Tawam , which includes the adjacent settlements of Al-Buraimi and Al Ain , on the border of Oman and the UAE Emirate of Abu Dhabi , lies

1872-626: The area of Khasab in northern part of the Musandam . Like the Ru'us al-Jibal , the area of Jebel Hafeet is noted for hosting rare flora and fauna. For example, in February 2019, an Arabian caracal was sighted here, and in March, a Blanford's fox , which has also been reported in the mountains of Ras Al-Khaimah. In September 2024 it was reported that the rare white-edged rock brown butterflies were spotted in

1924-472: The area. The Hajar are extensively grazed by domestic goats, camels and donkeys and the landscape has been cleared in parts for urban areas and for mining, which has damaged both vegetation and water supplies and uprooted traditional rural land management behaviours. Poaching of wildlife is another issue. The Oman government has created the Wadi Sareen Reserve and an area of Jebel Qahwan-Jebal Sebtah in

1976-519: The balancing anion, can occur to a greater or lesser degree. For example, in biological apatites there is appreciable substitution of sodium for calcium and carbonate for phosphate, in belovite sodium and cerium or lanthanum substitute for a pair of divalent metal ions, in germanate-pyromorphite germanate replaces phosphate and chloride, and in ellestadites silicate and sulphate replace pairs of phosphate anions. Metals forming smaller divalent ions, such as magnesium and iron, cannot substitute extensively for

2028-726: The calcium and phosphorus — impart the fluorescence, and adjustment of the fluorine-to-chlorine ratio alter the shade of white produced. This system has been almost entirely replaced by the Tri-Phosphor system. Apatites are also a proposed host material for storage of nuclear waste , along with other phosphates. Apatite is infrequently used as a gemstone . Transparent stones of clean color have been faceted, and chatoyant specimens have been cabochon -cut. Chatoyant stones are known as cat's-eye apatite , transparent green stones are known as asparagus stone , and blue stones have been called moroxite . If crystals of rutile have grown in

2080-476: The central mountains, indicating that the mountains are not currently deforming, even though the Zagros collision is. This indicates that the uplift that created the present day topography occurred in the past, possibly before the initiation of the Zagros collision , by a mechanism that is not fully understood. Oman's geological record is extremely valuable to geologists, and needs to be preserved . It contains

2132-519: The compressed solids is always elastically anisotropic, with BrAp exhibiting a markedly different behavior from those displayed by HOAp and ClAp. High-pressure p-V data were fitted to the Parsafar-Mason equation of state with an accuracy better than 1%. The monoclinic solid phases Ca 10 (PO 4 ) 6 (X) 2 (X= OH, Cl) and the molten hydroxyapatite compound have also been studied by molecular dynamics. Moon rocks collected by astronauts during

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2184-497: The crystal of apatite, in the right light the cut stone displays a cat's-eye effect. Major sources for gem apatite are Brazil, Myanmar, and Mexico. Other sources include Canada, Czech Republic, Germany, India, Madagascar, Mozambique, Norway, South Africa, Spain, Sri Lanka, and the United States. Apatite is occasionally found to contain significant amounts of rare-earth elements and can be used as an ore for those metals. This

2236-539: The final balancing anion can be fluoride (fluorapatites), chloride (chlorapatites), hydroxide (hydroxyapatites) or oxide (oxyapatites). Synthetic apatites add hypomanganate , hypochromate , bromide (bromoapatites), iodide (iodoapatites), sulfide (sulfoapatites), and selenide (selenoapatites). Evidence for natural sulfide substitution has been found in lunar rock samples. Furthermore, compensating substitution of monovalent and trivalent cations for calcium, of dibasic and tetrabasic anions for phosphate, and of

2288-512: The highest mountain ranges in the Arabian Peninsula , shared between northern Oman and eastern United Arab Emirates . Also known as "Oman Mountains", they separate the low coastal plain of Oman from the high desert plateau, and lie 50–100 km (31–62 miles) inland from the Gulf of Oman . Al ( اَلْ ) means "the", and Ḥajar ( حَجَر ) means "stone" or "rock". So al-Ḥajar ( اَلْحَجَر )

2340-669: The highest peak in the UAE. The mountains bordering the Shamailiyyah ( شَمَيْلِيَّة ) coast on the Gulf of Oman, forming parts of the northern UAE Emirates of Sharjah , Ras Al-Khaimah and Fujairah , may also be called the Shumayliyyah ( شُمَيْلِيَّة ). In this region is Jebel Al-Ḥeben ( جَبَل ٱلْحبن ; 25°7′33″N 56°9′33″E  /  25.12583°N 56.15917°E  / 25.12583; 56.15917 ). The mountains are rich in plant life compared to most of Arabia, including

2392-409: The low Samail Valley (which leads northeast to Muscat ). East of Samail are the Eastern Hajar ( Arabic : ٱلْحَجَر ٱلشَّرْقِي , romanized :  Al-Ḥajar Ash-Sharqī ), which run east (much closer to the coast) to the port city of Sur , almost at the easternmost point of Oman. The mountains to the west of Sama'il Valley, particularly those in Musandam Peninsula and the UAE, are known as

2444-460: The minimum amount of mineral-locked water was hypothetically converted to liquid, it would cover the Moon's surface in roughly one meter of water. The ectomycorrhizal fungi Suillus granulatus and Paxillus involutus can release elements from apatite. Release of phosphate from apatite is one of the most important activities of mycorrhizal fungi, which increase phosphorus uptake in plants. Apatite

2496-520: The modern convergence of the Australian passive margin under Eurasian oceanic crust, Arabian passive margin sediments became highly deformed and shortened forming an imbricated thrust belt. This also coincided with the emplacement of the Semail Ophiolite . By the early Maastrichtian , deformation ceased, and stable continental shelf conditions resumed. A second episode of deformation began during

2548-438: The most complete ophiolite on Earth, of which it is most famous for among geologists. The ophiolite sequence has spectacular pillow basalt (Geotimes pillow lava), as well as exposures of the fossil crust-mantle boundary ( moho ). Generally, ophiolites are obducted prior to continental collision , which highly deforms the structure of the original oceanic crust . However, because continental collision has not occurred in

2600-496: The mountains. Currently, the Arabian Plate is moving north relative to the Eurasian Plate at 2–3 cm (0.79–1.18 in) per year. Continental collision is occurring at the Zagros fold and thrust belt west of the Musandam Peninsula . This collisional plate boundary transitions into a subduction zone , towards the east. Here, oceanic crust of the Arabian Plate is subducted northwards beneath Eurasia , called

2652-420: The nearby Zagros Mountains of Iran . The geology of the Hajar can be grouped into four major tectonostratigraphic groups. Group one are the pre- Permian basement rocks, a sedimentary sequence of clastics , carbonates and evaporites . Group two are a middle Permian to Late Cretaceous sequence of continental shelf carbonates , which were deposited unconformably above the basement. Group three are

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2704-479: The rocks from groups one and two. Lastly, group four are late Cretaceous to Miocene shallow marine and terrestrial sedimentary rocks that were deposited on top of all three previous groups. The high topography is around two major culminations: Jabal Akhdar and Saih Hatat, which are large scale anticlines . The Saih Hatat culmination contains eclogite in the northeast at As Sifah. These rocks were subducted to about 80 km (50 mi) depth into

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