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Hormuz Formation
The Hormuz Formation, Hormuz Series, Hormuz Evaporites or Hormuz Group is a sequence of evaporites that were deposited during the Ediacaran (Late Neoproterozoic) to Early Cambrian, a period previously referred to as the Infra-Cambrian. Most exposures of this sequence are in the form of emergent salt diapirs within anticlines of the Zagros fold and thrust belt. As a result of their involvement in post-depositional salt tectonics, the internal stratigraphy of the sequence is relatively poorly understood. They are the lateral equivalent of the evaporite-bearing Ara Group in the South Oman Basin. Distribution The Hormuz Formation is known from a wide area of the Zagros Mountains and around and beneath the Persian Gulf. Two main depositional basins have been recognised, the North Gulf and South Gulf Basins, separated by the Qatar Arch. The basins were formed as a result of extensional tectonics towards the end of the Pan-African Orogeny. The main structure formed during this perio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zagros Mountains
The Zagros Mountains ( ar, جبال زاغروس, translit=Jibal Zaghrus; fa, کوههای زاگرس, Kuh hā-ye Zāgros; ku, چیاکانی زاگرۆس, translit=Çiyakani Zagros; Turkish: ''Zagros Dağları''; Luri: ''Kuh hā-ye Zāgros'' ''کویا زاگرس'') are a long mountain range in Iran, northern Iraq, and southeastern Turkey. This mountain range has a total length of . The Zagros mountain range begins in northwestern Iran and roughly follows Iran's western border while covering much of southeastern Turkey and northeastern Iraq. From this border region, the range continues to the southeast under also the waters of the Persian Gulf. It spans the southern parts of the Armenian highland, the whole length of the western and southwestern Iranian plateau, ending at the Strait of Hormuz. The highest point is Mount Dena, at . Geology The Zagros fold and thrust belt was mainly formed by the collision of two tectonic plates, the Eurasian Plate and the Arabian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Iraq
The geology of Iraq includes thick sequences of marine and continental sedimentary rocks over poorly understood basement rock, at the junction of the Arabian Plate, the Anatolian Plate, and the Iranian Plate. Geologic history, stratigraphy and tectonics The oldest rocks exposed at the surface in Iraq are part of the Cambrian and Ordovician age Khabour Quartzite Formation. Very little research and as of 1997 no boreholes have managed to reach underlying Precambrian rock. Most likely deeper basement rocks are part of the Afro-Arabian Plate formed into a craton in the Proterozoic. Northeastern Iraq has a thinned quasicontinental crust due to Neo-Tethys extensional faulting and plastic deformation of rocks. Paleozoic (539–251 million years ago) In the Paleozoic, the Arabian Plate was an extension of the African Plate and a part of Gondwana oriented to Paleo-Tethys Ocean to the north. Grabens formed, accumulating thicker sediments although sedimentary rocks overall ranged up to f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Iran
The main points that are discussed in the geology of Iran include the study of the geological and structural units or zones; stratigraphy; magmatism and igneous rocks; ophiolite series and ultramafic rocks; and orogenic events in Iran. Geological and structural units of Iran Considering geological and structural units of Iran, three main structural units or zones could be distinguished in Iran. These units or zones are separated from each other by ophiolite–bearing sutures. Other criteria such as structural style, crustal character and age of basement consolidation, age and intensity of deformation, age and nature of magmatism, are used to subdivide these major zones into smaller elements. The three major units and their main constituents could be defined as the southern, central and northern units. The southern unit has a crystalline basement consolidated in the Precambrian time and a platform–type Paleozoic development and comprises the Zagros folded belt, southern and south ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extensional Fault
An extensional fault is a fault caused by stretching of the Earth's crust. Stretching reduces the thickness and horizontally extends portions of the crust and/or lithosphere. In most cases such a fault is also a normal fault, but may create a shallower dip usually associated with a thrust fault. Extensional faults are generally planar. If the stress field is oriented with the maximum stress perpendicular to the Earth's surface, extensional faults will create an initial dip of the associated beds of about 60° from the horizontal. The faults will typically extend down to the base of the seismogenic layer In geophysics and seismology, the seismogenic layer covers the range of depths within the crust or lithosphere in which most earthquakes originate. The thickness is heavily dependent on location. For oceanic crust, the seismogenic layer thicknes .... As crustal stretching continues, the faults will rotate, resulting in steeply-dipping fault blocks between them. See also * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault (geology)
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A '' fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pan-African Orogeny
The Pan-African orogeny was a series of major Neoproterozoic orogenic events which related to the formation of the supercontinents Gondwana and Pannotia about 600 million years ago. This orogeny is also known as the Pan-Gondwanan or Saldanian Orogeny. The Pan-African orogeny and the Grenville orogeny are the largest known systems of orogenies on Earth. The sum of the continental crust formed in the Pan-African orogeny and the Grenville orogeny makes the Neoproterozoic the period of Earth's history that has produced most continental crust. History and terminology The term ''Pan-African'' was coined by for a tectono-thermal event at about 500 Ma when a series of mobile belts in Africa formed between much older African cratons. At the time, other terms were used for similar orogenic events on other continents, i.e. '' Brasiliano'' in South America; ''Adelaidean'' in Australia; and ''Beardmore'' in Antarctica. Later, when plate tectonics became generally accepted, the term ''Pan-A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extensional Tectonics
Extensional tectonics is concerned with the structures formed by, and the tectonic processes associated with, the stretching of a planetary body's crust or lithosphere. Deformation styles The types of structure and the geometries formed depend on the amount of stretching involved. Stretching is generally measured using the parameter ''β'', known as the ''beta factor'', where : \beta = \frac \,, ''t''0 is the initial crustal thickness and ''t''1 is the final crustal thickness. It is also the equivalent of the strain parameter ''stretch''. Low beta factor In areas of relatively low crustal stretching, the dominant structures are high to moderate angle normal faults, with associated half grabens and tilted fault blocks. High beta factor In areas of high crustal stretching, individual extensional faults may become rotated to too low a dip to remain active and a new set of faults may be generated. Large displacements may juxtapose syntectonic sediments against metamorphic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Persian Gulf
The Persian Gulf ( fa, خلیج فارس, translit=xalij-e fârs, lit=Gulf of Fars, ), sometimes called the ( ar, اَلْخَلِيْجُ ٱلْعَرَبِيُّ, Al-Khalīj al-ˁArabī), is a mediterranean sea in Western Asia. The body of water is an extension of the Indian Ocean located between Iran and the Arabian Peninsula.United Nations Group of Experts on Geographical NameWorking Paper No. 61, 23rd Session, Vienna, 28 March – 4 April 2006. accessed October 9, 2010 It is connected to the Gulf of Oman in the east by the Strait of Hormuz. The Shatt al-Arab river delta forms the northwest shoreline. The Persian Gulf has many fishing grounds, extensive reefs (mostly rocky, but also coral), and abundant pearl oysters, however its ecology has been damaged by industrialization and oil spills. The Persian Gulf is in the Persian Gulf Basin, which is of Cenozoic origin and related to the subduction of the Arabian Plate under the Zagros Mountains. The current f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Society
The Geological Society of London, known commonly as the Geological Society, is a learned society based in the United Kingdom. It is the oldest national geological society in the world and the largest in Europe with more than 12,000 Fellows. Fellows are entitled to the postnominal FGS (Fellow of the Geological Society), over 2,000 of whom are Chartered Geologists (CGeol). The Society is a Registered Charity, No. 210161. It is also a member of the Science Council, and is licensed to award Chartered Scientist to qualifying members. The mission of the society is: "Making geologists acquainted with each other, stimulating their zeal, inducing them to adopt one nomenclature, facilitating the communication of new facts and ascertaining what is known in their science and what remains to be discovered". History The Society was founded on 13 November 1807 at the Freemasons' Tavern, Great Queen Street, in the Covent Garden district of London. It was partly the outcome of a previous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evaporite
An evaporite () is a water- soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as ocean deposits, and non-marine, which are found in standing bodies of water such as lakes. Evaporites are considered sedimentary rocks and are formed by chemical sediments. Formation of evaporite rocks Although all water bodies on the surface and in aquifers contain dissolved salts, the water must evaporate into the atmosphere for the minerals to precipitate. For this to happen, the water body must enter a restricted environment where water input into this environment remains below the net rate of evaporation. This is usually an arid environment with a small basin fed by a limited input of water. When evaporation occurs, the remaining water is enriched in salts, and they precipitate when the water becomes supersaturated. Evaporite depositio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
