1.
Egypt
–
Egypt, officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia by a land bridge formed by the Sinai Peninsula. Egypt is a Mediterranean country bordered by the Gaza Strip and Israel to the northeast, the Gulf of Aqaba to the east, the Red Sea to the east and south, Sudan to the south, and Libya to the west. Across the Gulf of Aqaba lies Jordan, and across from the Sinai Peninsula lies Saudi Arabia, although Jordan and it is the worlds only contiguous Afrasian nation. Egypt has among the longest histories of any country, emerging as one of the worlds first nation states in the tenth millennium BC. Considered a cradle of civilisation, Ancient Egypt experienced some of the earliest developments of writing, agriculture, urbanisation, organised religion and central government. One of the earliest centres of Christianity, Egypt was Islamised in the century and remains a predominantly Muslim country. With over 92 million inhabitants, Egypt is the most populous country in North Africa and the Arab world, the third-most populous in Africa, and the fifteenth-most populous in the world. The great majority of its people live near the banks of the Nile River, an area of about 40,000 square kilometres, the large regions of the Sahara desert, which constitute most of Egypts territory, are sparsely inhabited. About half of Egypts residents live in areas, with most spread across the densely populated centres of greater Cairo, Alexandria. Modern Egypt is considered to be a regional and middle power, with significant cultural, political, and military influence in North Africa, the Middle East and the Muslim world. Egypts economy is one of the largest and most diversified in the Middle East, Egypt is a member of the United Nations, Non-Aligned Movement, Arab League, African Union, and Organisation of Islamic Cooperation. Miṣr is the Classical Quranic Arabic and modern name of Egypt. The name is of Semitic origin, directly cognate with other Semitic words for Egypt such as the Hebrew מִצְרַיִם, the oldest attestation of this name for Egypt is the Akkadian
2.
North Africa
–
North Africa or Northern Africa is the northernmost region of Africa. The United Nationss definition of Northern Africa is, Algeria, Egypt, Libya, Morocco, Sudan, Tunisia, the countries of Algeria, Morocco, Tunisia, and Libya are often collectively referred to as the Maghreb, which is the Arabic word for sunset. Egypt lies to the northeast and encompasses part of West Asia, while Sudan is situated on the edge of the Sahel, Egypt is a transcontinental country because of the Sinai Peninsula, which geographically lies in Western Asia. North Africa also includes a number of Spanish possessions, the Canary Islands and Madeira in the North Atlantic Ocean northwest of the African mainland are included in considerations of the region. From 3500 BC, following the abrupt desertification of the Sahara due to changes in the Earths orbit. The Islamic influence in the area is significant, and North Africa is a major part of the Muslim world. Some researchers have postulated that North Africa rather than East Africa served as the point for the modern humans who first trekked out of the continent in the Out of Africa migration. The Atlas Mountains extend across much of Morocco, northern Algeria and Tunisia, are part of the mountain system that also runs through much of Southern Europe. They recede to the south and east, becoming a steppe landscape before meeting the Sahara desert, the sediments of the Sahara overlie an ancient plateau of crystalline rock, some of which is more than four billion years old. Sheltered valleys in the Atlas Mountains, the Nile Valley and Delta, a wide variety of valuable crops including cereals, rice and cotton, and woods such as cedar and cork, are grown. Typical Mediterranean crops, such as olives, figs, dates and citrus fruits, the Nile Valley is particularly fertile, and most of the population in Egypt and Sudan live close to the river. Elsewhere, irrigation is essential to improve yields on the desert margins. The inhabitants of Saharan Africa are generally divided in a manner corresponding to the principal geographic regions of North Africa, the Maghreb, the Nile valley. The edge of the Sahel, to the south of Egypt has mainly been inhabited by Nubians, Ancient Egyptians record extensive contact in their Western desert with people that appear to have been Berber or proto-Berber, as well as Nubians from the south. They have contributed to the Arabized Berber populations, the official language or one of the official languages in all of the countries in North Africa is Arabic. The people of the Maghreb and the Sahara regions speak Berber languages and several varieties of Arabic, the Arabic and Berber languages are distantly related, both being members of the Afroasiatic language family. The Tuareg Berber languages are more conservative than those of the coastal cities. Over the years, Berbers have been influenced by contact with cultures, Greeks, Phoenicians, Egyptians, Romans, Vandals, Arabs, Europeans
3.
Valley
–
A valley is a low area between hills, often with a river running through it. In geology, a valley or dale is a depression that is longer than it is wide, the terms U-shaped and V-shaped are descriptive terms of geography to characterize the form of valleys. Most valleys belong to one of two main types or a mixture of them, with respect to the cross section of the slopes or hillsides. A valley in its broadest geographic sense is known as a dale. A valley through which a river runs may also be referred to as a vale, a small, secluded, and often wooded valley is known as a dell or in Scotland as a glen. A wide, flat valley through which a river runs is known in Scotland as a strath, a mountain cove is a small valley, closed at one or both ends, in the central or southern Appalachian Mountains which sometimes results from the erosion of a geologic window. A small valley surrounded by mountains or ridges is sometimes known as a hollow, a deep, narrow valley is known as a cwm. Similar geological structures, such as canyons, ravines, gorges, gullies, chines, a valley formed by erosion is called an erosional valley, a valley formed by geologic events such as drop faults or the rise of highlands is called a structural valley. A valley formed by flowing water, or river valley, is usually V-shaped, the exact shape will depend on the characteristics of the stream flowing through it. Rivers with steep gradients, as in mountain ranges, produce steep walls, shallower slopes may produce broader and gentler valleys. However, in the lowest stretch of a river, where it approaches its base level, it begins to deposit sediment, in prehistory, the rivers were used as a source of fresh water and food, as well as a place to wash and a sewer. The proximity of water moderated temperature extremes and provided a source for irrigation, most of the first civilizations developed from these river valley communities. In geography, a vale is a river valley, usually with a particularly wide flood plain or flat valley bottom. In Southern England, vales commonly occur between the escarpment slopes of pairs of chalk formations, where the dome has been eroded, exposing less resistant underlying rock. Rift valleys, such as the Albertine Rift, are formed by the expansion of the Earths crust due to tectonic activity beneath the Earths surface, there are various forms of valley associated with glaciation that may be referred to as glacial valleys. A valley carved by glaciers is normally U-shaped, the valley becomes visible upon the recession of the glacier that forms it. When the ice recedes or thaws, the remains, often littered with small boulders that were transported within the ice. Floor gradient does not affect the shape, it is the glaciers size that does
4.
Ephemerality
–
Ephemerality is the concept of things being transitory, existing only briefly. Because different people may value the passage of time differently, the concept of ephemerality is a relative one, an ephemeral waterbody is a wetland, spring, stream, river, pond or lake that only exists for a short period following precipitation or snowmelt. They are not the same as intermittent or seasonal waterbodies, which exist for longer periods, examples of ephemeral streams are the Luni river in Rajasthan, India, Ugab River in Southern Africa, and a number of small ephemeral watercourses that drain Talak in northern Niger. Other notable ephemeral rivers include the Todd River and Sandover River in Central Australia as well as the Son River, Batha River, any endorheic basin, or closed basin, that contains a playa or dry lake at its drainage lowpoint can become an ephemeral lake. Examples include Lake Carnegie in Western Australia, Lake Cowal in New South Wales, Mystic Lake and Rogers Lake in California, even the driest and lowest place in North America, Death Valley, became flooded with a short-lived ephemeral lake in the spring of 2005. There are also ephemeral islands such as Banua Wuhu and Home Reef and these islands appear when volcanic activity increases their height above sea level, but disappear over several years due to wave erosion. Bassas da India, on the hand, is a near-sea level island that appears only at low tide. Many plants are adapted to a lifestyle, in which they spend most of the year or longer as seeds before conditions are right for a brief period of growth. The spring ephemeral plant mouse-ear cress is a well-known example, animals can be ephemeral, with brine shrimp and the mayfly being examples. The placenta is considered an ephemeral organ present during gestation and pregnancy, ephemeral can also be used as an adjective to refer to a fast-deteriorating importance or temporary nature of an object to a person. Brands are notoriously ephemeral assets, and magazine publishing was once much more ephemeral than it is today, a number of art forms can be considered ephemeral because of their temporary nature. Early land art and all sand sculptures, ice sculptures and chalk drawings on footpaths are examples of ephemeral art, G. Augustine Lynas and Duthain Dealbh create ephemeral sculptures. Ephemeroptera Christine Buci-Glucksmann, Esthetique De Lephemere, Galilee, ISBN 2-7186-0622-3
5.
Rain
–
Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and then precipitated—that is, become heavy enough to fall under gravity. Rain is a component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides suitable conditions for many types of ecosystems, as well as water for power plants. The major cause of production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts. If enough moisture and upward motion is present, precipitation falls from convective clouds such as cumulonimbus which can organize into narrow rainbands. On the leeward side of mountains, desert climates can exist due to the dry air caused by downslope flow which causes heating and drying of the air mass, the movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes. The urban heat island effect leads to increased rainfall, both in amounts and intensity, downwind of cities, global warming is also causing changes in the precipitation pattern globally, including wetter conditions across eastern North America and drier conditions in the tropics. The globally averaged annual precipitation over land is 715 mm, climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes. Rainfall is measured using rain gauges, rainfall amounts can be estimated by weather radar. Rain is also known or suspected on other planets, where it may be composed of methane, neon, sulfuric acid, or even iron rather than water. Air contains water vapor, and the amount of water in a mass of dry air. The amount of moisture in air is commonly reported as relative humidity. How much water vapor a parcel of air can contain before it becomes saturated, warmer air can contain more water vapor than cooler air before becoming saturated. Therefore, one way to saturate a parcel of air is to cool it, the dew point is the temperature to which a parcel must be cooled in order to become saturated. There are four mechanisms for cooling the air to its dew point, adiabatic cooling, conductive cooling, radiational cooling. Adiabatic cooling occurs when air rises and expands, the air can rise due to convection, large-scale atmospheric motions, or a physical barrier such as a mountain. Conductive cooling occurs when the air comes into contact with a surface, usually by being blown from one surface to another. Radiational cooling occurs due to the emission of infrared radiation, either by the air or by the surface underneath, evaporative cooling occurs when moisture is added to the air through evaporation, which forces the air temperature to cool to its wet-bulb temperature, or until it reaches saturation
6.
Guadalcanal, Seville
–
Guadalcanal is a village in the province of Seville, in the autonomous community of Andalusia, Spain. The name was given to the island of Guadalcanal in the Solomon Islands in 1568, the name was chosen by Pedro de Ortega Valencia who had been born in the village. He was a subordinate of Spanish explorer and navigator, Álvaro de Mendaña de Neira, in 2006 there were 2,970 inhabitants. It has an area of 275 square kilometres and a density of 10,6 people per square-km. It is at an altitude of 662 metres, in a valley between the Sierra del Agua and the Sierra del Viento, in the region of the North Mountains of Seville, but it is more likely to be a mixture of Arabic Wad and Spanish del Canal. Other names were Tereses or Tereja or Canani with the Iberians and it was reconquered by the Order of Santiago in 1241 from the Moors, then Guadalcanal belonged to the Leóns province as well as other parts of Extremadura. In the ecclesiastical matter, it belonged to the Santa María de Tendudia vicary, Guadalcanal was fortified by means of a now-ruined wall which was demolished because the village took part in the Guerra de las Comunidades de Castilla. In the mid-16th century, the area had some silver mines financed by the Fugger family, the village suffered a crisis in the 19th century, which caused the four nunneries in the village to close. As other rural communities in Spain, it faced an exodus of its inhabitants to the cities in the 20th century. Página web del pintor Fernando Díaz Mirón Mirador La Capitana en el término municipal de Guadalcanal Vídeos de Guadalcanal
7.
Guadalajara, Castilla-La Mancha
–
Guadalajara is a city and municipality in the autonomous community of Castile–La Mancha, Spain, and in the natural region of La Alcarria. It is the capital of the province of Guadalajara and it is located roughly 60 kilometres northeast of Madrid on the Henares River, and has a population of 84,803. A Roman town called Arriaca, possibly founded by a culture, is known to have been located in that region. There is however no proof of its existence, only references in texts such as the Ruta Antonina. The city, as Caracca, was incorporated into the Roman province of Hispania Tarraconensis, the city was on the high road from Emerita to Caesaraugusta,22 M. P. northeast of Complutum. The town of Guadalajara was founded by the Andalusians in the 8th century and they named it Wādī-al-Ḥajāra, meaning Valley of Stones, in theory the literal translation of the Iberian name, meaning Stony River. The history of the town during the Al-Andalus period was significant and they built monuments including the Moorish Bridge over the Henares River, the now ruined old Alcázar, and a mosque which later became the former Cathedral of St. Mary. In 1085, Guadalajara was taken by the Christian forces of Alfonso VI, the chronicles say that the Christian army was led by Alvar Fanez de Minaya, one of the lieutenants of El Cid. From 1085 until the Battle of Las Navas de Tolosa in 1212, the city suffered wars against the Almoravid, in 1219, the king Fernando III gave a new fuero to the city. During the reign of Alfonso X of Castile, the protection of the king allowed the city to develop its economy by protecting merchants, during the 14th century, the Mendoza family was prominent in Guadalajara. This family included Íñigo López de Mendoza, also known as Marqués de Santillana, the Mendoza family held the title of Dukes and Duchesses of El Infantado from 1475. In 1460, King Henry IV gave Guadalajara the title of City, Guadalajara was the birthplace of conquistador Nuño de Guzmán, who commissioned in 1542 the foundation of Guadalajara, Mexico. During the War of the Spanish Succession, Guadalajara was sacked, King Philip V ordered the establishment of the Real Fábrica de Paños which was situated in the Alcazar till the early 19th century. In this period, the Mendoza Family ordered the building of El Palacio del Infantado as their main residence and it was completed in the early 1480s and it is considered by many the oldest surviving building built in a pure Renaissance style outside Italy. The 19th century started with two setbacks, the damages caused by the Peninsular War and the closing of the Real Fábrica de Paños in 1822. In 1808, Guadalajara was taken by the French Army led by General Hugo, in 1840 Guadalajara was established as the capital of the province with the same name by the Plan de Burgos. The Academy of Military Engineers was brought to the city, Guadalajara was the scene of many actions during the Spanish Civil War. On 24 July 1936, during the phase after the revolt of 19 July
8.
India
–
India, officially the Republic of India, is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and it is bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast. It shares land borders with Pakistan to the west, China, Nepal, and Bhutan to the northeast, in the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives. Indias Andaman and Nicobar Islands share a border with Thailand. The Indian subcontinent was home to the urban Indus Valley Civilisation of the 3rd millennium BCE, in the following millennium, the oldest scriptures associated with Hinduism began to be composed. Social stratification, based on caste, emerged in the first millennium BCE, early political consolidations took place under the Maurya and Gupta empires, the later peninsular Middle Kingdoms influenced cultures as far as southeast Asia. In the medieval era, Judaism, Zoroastrianism, Christianity, and Islam arrived, much of the north fell to the Delhi sultanate, the south was united under the Vijayanagara Empire. The economy expanded in the 17th century in the Mughal empire, in the mid-18th century, the subcontinent came under British East India Company rule, and in the mid-19th under British crown rule. A nationalist movement emerged in the late 19th century, which later, under Mahatma Gandhi, was noted for nonviolent resistance, in 2015, the Indian economy was the worlds seventh largest by nominal GDP and third largest by purchasing power parity. Following market-based economic reforms in 1991, India became one of the major economies and is considered a newly industrialised country. However, it continues to face the challenges of poverty, corruption, malnutrition, a nuclear weapons state and regional power, it has the third largest standing army in the world and ranks sixth in military expenditure among nations. India is a constitutional republic governed under a parliamentary system. It is a pluralistic, multilingual and multi-ethnic society and is home to a diversity of wildlife in a variety of protected habitats. The name India is derived from Indus, which originates from the Old Persian word Hindu, the latter term stems from the Sanskrit word Sindhu, which was the historical local appellation for the Indus River. The ancient Greeks referred to the Indians as Indoi, which translates as The people of the Indus, the geographical term Bharat, which is recognised by the Constitution of India as an official name for the country, is used by many Indian languages in its variations. Scholars believe it to be named after the Vedic tribe of Bharatas in the second millennium B. C. E and it is also traditionally associated with the rule of the legendary emperor Bharata. Gaṇarājya is the Sanskrit/Hindi term for republic dating back to the ancient times, hindustan is a Persian name for India dating back to the 3rd century B. C. E. It was introduced into India by the Mughals and widely used since then and its meaning varied, referring to a region that encompassed northern India and Pakistan or India in its entirety
9.
Maharashtra
–
Four Maharashtra is a state in the western region of India and is Indias second-most populous state and third-largest state by area. It is the wealthiest Indian state and it is also the worlds second-most populous sub-national entity. It has over 112 million inhabitants and its capital, Mumbai, has a population of approximately 18 million, Nagpur is Maharashtras second capital as well as its winter capital. Maharashtras business opportunities along with its potential to offer a standard of living attract migrants from all over India. Ancient and medieval Maharashtra included the empires of the Satavahana dynasty, Rashtrakuta dynasty, Western Chalukyas, Mughals, the major rivers of the state are Godavari, and Krishna. The Narmada and Tapti Rivers flow near the border between Maharashtra and Madhya Pradesh and Gujarat, Maharashtra is the second most urbanised state in India. The state has several popular Hindu places of pilgrimage including Pandharpur, Dehu and Alandi, other places that attract pilgrims from other parts of India and beyond include Hazur Sahib Gurudwara at Nanded, Sai Baba shrine at Shirdi and Dikshabhumi at Nagpur. Maharashtra is the wealthiest and one of the most developed states in India, as of 2011, the state had a per capita income of ₹1.0035 lakh, more than the national average of ₹0.73 lakh. Its GDP per capita crossed the ₹1.20 lakh threshold for the first time in 2013, however, as of 2014, the GDP per capita reduced to ₹1.03 lakh Agriculture and industries are the largest parts of the states economy. Major industries include chemical products, electrical and non-electrical machinery, textiles, petroleum, Jai Maharashtra The modern Marathi language developed from the Maharashtri Prakrit, and the word Mahratta is found in the Jain Maharashtri literature. The terms Maharashtra, Maharashtri, Marathi and Maratha may have derived from the same root, however, their exact etymology is uncertain. But the Marathas as a people do not seem to be mentioned before the thirteenth or fourteenth century, the most widely accepted theory among the linguistic scholars is that the words Maratha and Maharashtra ultimately derived from a combination of Maha and rashtrika. The word rashtrika is a Sanskritized form of Ratta, the name of a tribe or dynasty of petty chiefs ruling in the Deccan region. Another theory is that the term is derived from Maha and ratha / rathi, an alternative theory states that the term derives from the word Maha and Rashtra. However, this theory has not found acceptance among scholars who believe it to be the Sanskritised interpretation of later writers. Maharashtra was ruled by the Maurya Empire in the 4th and 3rd centuries BCE, around 230 BCE Maharashtra came under the rule of the Satavahana dynasty for 400 years. The greatest ruler of the Satavahana Dynasty was Gautamiputra Satakarni, in 90 CE Vedishri, son of the Satavahana king Satakarni, the Lord of Dakshinapatha, wielder of the unchecked wheel of Sovereignty, made Junnar, thirty miles north of Pune, the capital of his kingdom. The state was ruled by Western Satraps, Gupta Empire, Gurjara-Pratihara, Vakataka, Kadambas, Chalukya Empire, Rashtrakuta Dynasty, and Western Chalukya before finally
10.
Monsoon
–
Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern, although technically there is also a dry phase. The term is sometimes used for locally heavy but short-term rains. The major monsoon systems of the world consist of the West African and Asia-Australian monsoons, the inclusion of the North and South American monsoons with incomplete wind reversal has been debated. The south-west monsoon winds are called Nairutya Maarut in India, the English monsoon came from Portuguese monção, ultimately from Arabic mawsim and/or Hindi mausam, perhaps partly via early modern Dutch monsun. Strengthening of the Asian monsoon has been linked to the uplift of the Tibetan Plateau after the collision of the Indian sub-continent and Asia around 50 million years ago. Because of studies of records from the Arabian Sea and that of the wind-blown dust in the Loess Plateau of China, testing of this hypothesis awaits deep ocean sampling by the Integrated Ocean Drilling Program. The monsoon has varied significantly in strength since this time, largely linked to climate change. A study of marine plankton suggested that the Indian Monsoon strengthened around 5 million years ago, then, during ice periods, the sea level fell and the Indonesian Seaway closed. When this happened, cold waters in the Pacific were impeded from flowing into the Indian Ocean and it is believed that the resulting increase in sea surface temperatures in the Indian Ocean increased the intensity of monsoons. Five episodes during the Quaternary at 2.22 Ma,1.83 Ma,0.68 Ma,0.45 Ma and 0.04 Ma were identified which showed a weakening of Leeuwin Current. The weakening of the LC would have an effect on the sea surface temperature field in the Indian Ocean, thus these five intervals could probably be those of considerable lowering of SST in the Indian Ocean and would have influenced Indian monsoon intensity. The impact of monsoon on the weather is different from place to place. In some places there is just a likelihood of having a more or less rain. In other places, quasi semi-deserts are turned into green grasslands where all sorts of plants. The Indian Monsoon turns large parts of India from a kind of semi-desert into green lands, see photos only taken 3 months apart in the Western Ghats. In places like this it is crucial for farmers to have the right timing for putting the seeds on the fields, Monsoons are large-scale sea breezes which occur when the temperature on land is significantly warmer or cooler than the temperature of the ocean. These temperature imbalances happen because oceans and land absorb heat in different ways, in contrast, dirt, sand, and rocks have lower heat capacities, and they can only transmit heat into the earth by conduction and not by convection. Therefore, bodies of water stay at an even temperature
11.
Alluvial fan
–
An alluvial fan is a fan- or cone-shaped deposit of sediment crossed and built up by streams. If a fan is built up by debris flows it is called a debris cone or colluvial fan. These flows come from a point source at the apex of the fan. Fans are typically found where a canyon draining from mountainous terrain emerges out onto a flatter plain, a convergence of neighboring alluvial fans into a single apron of deposits against a slope is called a bajada, or compound alluvial fan. As a streams gradient decreases, it drops coarse-grained material and this reduces the capacity of the channel and forces it to change direction and gradually build up a slightly mounded or shallow conical fan shape. The deposits are poorly sorted. There will be iso-transport energy lines forming concentric arcs about the point at the apex of the fan. Thus the material will tend to be deposited equally about these lines, Alluvial fans are often found in desert areas subject to periodic flash floods from nearby thunderstorms in local hills. The typical watercourse in an arid climate has a large, funnel-shaped basin at the top, leading to a narrow defile, multiple braided streams are usually present and active during water flows. Phreatophytes are plants that are concentrated at the base of alluvial fans. They have long tap roots 30 to 50 feet to water that has seeped through the fan and hit an impermeable layer, sometimes collecting in springs. These stands of shrubs cling to the soil at their bases, Alluvial fans also develop in wetter climates. Along the upper Koshi tributaries, tectonic forces elevate the Himalayas several millimeters annually, uplift is approximately in equilibrium with erosion, so the river annually carries some 100 million cubic meters of sediment as it exits the mountains. Deposition of this magnitude over millions of years is more than sufficient to account for the megafan, despite overpopulation on the plains, this bhabar zone is highly malarial and has remained largely uninhabited. In North America, streams flowing into Californias Central Valley have deposited smaller, such as that of the Kings River flowing out of the Sierra Nevada creates a low divide, turning the south end of the San Joaquin Valley into an endorheic basin without a connection to the ocean. Alluvial fans are subject to flooding and can be more dangerous than the upstream canyons that feed them. Their slightly convex perpendicular surfaces cause water to spread widely until there is no zone of refuge, if the gradient is steep, active transport of materials down the fan creates a moving substrate that is inhospitable to travel on foot or wheels. But as the gradient diminishes downslope, water comes down from above faster than it can flow away downstream, in the case of the Koshi River, the huge sediment load and megafans slightly convex transverse surface conspire against engineering efforts to contain peak flows inside manmade embankments
12.
Sabkha
–
Sabkha is a phonetic translation of the Arabic word for a salt flat. Sabkhas are supratidal, forming along coastlines and are characterized by evaporite-carbonate deposits with some siliciclastics. Sabkhas form subaerial, prograding and shoaling-upward sequences that have a thickness of a meter or less. The accepted type locality is along the coast of the Persian Gulf in the United Arab Emirates, the origin and progression of sabkha development in the Persian Gulf is discussed by Al-Farraj. In the khor-lagoon-sabkha model, a rise in sea-level floods coastal areas. If the features silt up, or the land rises, or the sea level falls, then the water evaporates, leaving a flat salt pan. If the coastal region has irregular topography, then the flooding creates large independent creeks, a khor is a shallow, subtidal flat or tidal inlet. The inlet may host grey mangroves, depending on whether less saline water is available from wadis or groundwater, as sediment begins to accumulate, the khors become more shallow and form a lagoon, or intertidal flat. The lagoons continue to fill until the floor is exposed at low tide. An immature sabkha will be inundated during higher than normal spring tides, after rainstorms, mature sabkhas are only flooded after heavy rainstorms and may eventually coalesce to form a sabkha coastal plain. These coastal plains are flat, with reliefs between 10–50 cm, and their seaward slope can be as little as 1,1,000. The flatness of a sabkha is enhanced by aeolian siliciclastic dust being deposited in the topographic lows with most of the caused by evaporites. These environments can be found laterally contemporaneous in parallel belts to the coast as well, coral reefs, barrier islands, and oolite shoals form the barrier with the open shelf. Inland of this are the supratidal sabkhas, the sabkhas can be as wide as 15 km when seaward of dune fields supplying large amounts of sediment. Sabkhas seaward of low outcrops of Miocene carbonate-evaporites or alluvial fans off the Oman fold, if the coast has dune fields, then flooding creates many smaller pools between the crests of the dunes. In some parts of the world, these lakes can form in inland deserts. For example, large parts of the Empty Quarter in Saudi Arabia, in some places, the sabkha connect to form long accessible corridors into the desert. The third picture shows the south of the crescent-shaped Liwa Oasis in the southern UAE
.jpg)
