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Vertisol
A vertisol, or vertosol, is a soil type in which there is a high content of expansive clay minerals, many of them known as montmorillonite, that form deep cracks in drier seasons or years. In a phenomenon known as argillipedoturbation, alternate shrinking and swelling causes ''self-ploughing'', where the soil material consistently mixes itself, causing some vertisols to have an extremely deep A horizon and no B horizon. (A soil with no B horizon is called an ''A/C soil''). This heaving of the underlying material to the surface often creates a microrelief known as '' gilgai''. Vertisols typically form from highly basic rocks, such as basalt, in climates that are seasonally humid or subject to erratic droughts and floods, or that impeded drainage. Depending on the parent material and the climate, they can range from grey or red to the more familiar deep black (known as "black earths" in Australia, "black gumbo" in East Texas, "black cotton" soils in East Africa, and "vlei soils" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argillipedoturbation
Argillipedoturbation, sometimes referred to as self-mulching, is a process of soil mixing caused by the shrinking and swelling of the smectite clays contained in the soil. It is an effect specific to soils of the vertisolic variety, and is triggered by the constant cycles of wetting and drying It is characterized by wide (up to ), deep ( or more) vertical cracks in the solum that contain differing materials from the rest of the soil layer they are found in, as well as sloughed-in surface materials. In order for argillipedoturbation to occur, the soil must be at least 30% clay content. The expression of argillipedoturbation depends to a large degree on the exact clay content of the soil, as well as on what other minerals make up the soil composition. Argillipedoturbation can be strong enough that it can affect the soil horizons by combining the different horizons, making them difficult to distinguish. It can also result in a gently-rolling surface referred to as gilgai topography an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deccan Plateau
The large Deccan Plateau in southern India is located between the Western Ghats and the Eastern Ghats, and is loosely defined as the peninsular region between these ranges that is south of the Narmada river. To the north, it is bounded by the Satpura and Vindhya Ranges. A rocky terrain marked by boulders, its elevation ranges between , with an average of about .Editors of Encyclopedia Britannica (2014), ''Deccan plateau India''Encyclopaedia Britannica/ref> It is sloping generally eastward. Thus, its principal rivers—the Godavari, Krishna, and Kaveri (Cauvery)—flow eastward from the Western Ghats to the Bay of Bengal. The plateau is drier than the coastal region of southern India and is arid in places. It produced some of the major dynasties in Indian history, including the Pallavas, Satavahana, Vakataka, Chalukya, and Rashtrakuta dynasties, also the Western Chalukya Empire, the Kadambas, the Yadava dynasty, the Kakatiya Empire, the Musunuri Nayakas regime, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gilgai
A gilgai is a small, ephemeral#Geographical examples, ephemeral lake formed from a depression in the soil surface in expanding clay soils. Additionally, the term "gilgai" is used to refer to the overall micro-relief in such areas, consisting of mounds and depressions, not just the lakes themselves. The name comes from an Australian Aboriginal word meaning small water hole. These pools are commonly a few metres across and less than deep, however in some instances they may be several metres deep and up to across. Gilgais are found worldwide wherever Vertisol, cracking clay soils and pronounced wet and dry seasons are present. Gilgais are also called "melonholes, crabholes, hogwallows or puff and shelf formations". Gilgais are thought to form in vertisols through repeated cycles of swelling of the clay when wet and subsequent shrinkage upon drying. This action, known as argillipedoturbation, causes the soil to crack when dry and loose soil material then fills these cracks. When the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Expansive Clay
Expansive clay is a clay soil that is prone to large volume changes (swelling and shrinking) that are directly related to changes in water content. Soils with a high content of expansive minerals can form deep cracks in drier seasons or years; such soils are called vertisols. Soils with smectite clay minerals, including montmorillonite and bentonite Bentonite () is an absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelling capacity than Ca-m ..., have the most dramatic shrink-swell capacity. The mineral make-up of this type of soil is responsible for the moisture retaining capabilities. All clays consist of mineral sheets packaged into layers, and can be classified as either 1:1 or 2:1. These ratios refer to the proportion of tetrahedral sheets to octahedral sheets. Octahedral sheets are sandwiched between two tetrahedral she ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedoturbation
Perturbation (from Latin: ''perturbare'' "to confuse, disorder, disturb", from ''per''- "through" + ''turbare'' "disturb, confuse," from ''turba'' "turmoil, crowd") is a set of pedology (soil study) and sedimentary geology processes relating to changes in the nature of water-borne alluvial sediments and ''in situ'' soil deposits over time. * Pedoturbation (from Greek: πέδον (''pédon''), "soil") involves mixing between soil horizons, and is an important factor in soil formation. Pedoturbation includes churning clays, cryoturbation, and bioturbation. Types of bioturbation include faunal pedoturbation (animal burrowing), and floral pedoturbation (root growth, tree-uprootings). Pedoturbation transforms soils through destratification, mixing, and sorting, as well as creating preferential flow paths for soil gas and infiltrating water. The zone of active bioturbation is termed the soil biomantle. * Soil perturbation that is not pedoturbation. Precipitation of surface salts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nigeria
Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf of Guinea to the south in the Atlantic Ocean. It covers an area of , and with a population of over 225 million, it is the most populous country in Africa, and the world's sixth-most populous country. Nigeria borders Niger in the north, Chad in the northeast, Cameroon in the east, and Benin in the west. Nigeria is a federal republic comprising of 36 states and the Federal Capital Territory, where the capital, Abuja, is located. The largest city in Nigeria is Lagos, one of the largest metropolitan areas in the world and the second-largest in Africa. Nigeria has been home to several indigenous pre-colonial states and kingdoms since the second millennium BC, with the Nok civilization in the 15th century BC, marking the first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. 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 north; and Bangladesh and Myanmar to the east. In the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives; its Andaman and Nicobar Islands share a maritime border with Thailand, Myanmar, and Indonesia. Modern humans arrived on the Indian subcontinent from Africa no later than 55,000 years ago., "Y-Chromosome and Mt-DNA data support the colonization of South Asia by modern humans originating in Africa. ... Coalescence dates for most non-European populations average to between 73–55 ka.", "Modern human beings—''Homo sapiens''—originated in Africa. Then, interm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatemala, Belize, and the Caribbean Sea; and to the east by the Gulf of Mexico. Mexico covers ,Mexico ''''. . making it the world's 13th-largest country by are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Texas
Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by both area (after Alaska) and population (after California). Texas shares borders with the states of Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the west, and the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas to the south and southwest; and has a coastline with the Gulf of Mexico to the southeast. Houston is the most populous city in Texas and the fourth-largest in the U.S., while San Antonio is the second most populous in the state and seventh-largest in the U.S. Dallas–Fort Worth and Greater Houston are, respectively, the fourth- and fifth-largest metropolitan statistical areas in the country. Other major cities include Austin, the second most populous s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New South Wales
) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_date = Colony of New South Wales , established_title2 = Establishment , established_date2 = 26 January 1788 , established_title3 = Responsible government , established_date3 = 6 June 1856 , established_title4 = Federation of Australia, Federation , established_date4 = 1 January 1901 , named_for = Wales , demonym = , capital = Sydney , largest_city = capital , coordinates = , admin_center = Local government areas of New South Wales, 128 local government areas , admin_center_type = Administration , leader_title1 = Monarchy of Australia, Monarch , leader_name1 = Charles III , leader_title2 = Governor of New South Wales, Governor , leader_name2 = Margaret Beazley , leader_title3 = Premier of New South Wales, Premie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraná River
The Paraná River ( es, Río Paraná, links=no , pt, Rio Paraná, gn, Ysyry Parana) is a river in south-central South America, running through Brazil, Paraguay, and Argentina for some ."Parana River". Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica Inc., 2012. Web. 26 May. 2012 . "Rio de la Plata". Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica Inc., 2012. Web. 26 May. 2012 Among South American rivers, it is second in length only to the Amazon River. It merges with the Paraguay River and then farther downstream with the Uruguay River to form the Río de la Plata and empties into the Atlantic Ocean. The first European to go up the Paraná River was the Venetian explorer Sebastian Cabot, in 1526, while working for Spain. A drought hit the river in 2021, causing a 77-year low. Etymology In eastern South America there is "an immense number of river names containing the element ''para-'' or ''parana-''", ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrace
Thrace (; el, Θράκη, Thráki; bg, Тракия, Trakiya; tr, Trakya) or Thrake is a geographical and historical region in Southeast Europe, now split among Bulgaria, Greece, and Turkey, which is bounded by the Balkan Mountains to the north, the Aegean Sea to the south, and the Black Sea to the east. It comprises southeastern Bulgaria (Northern Thrace), northeastern Greece ( Western Thrace), and the European part of Turkey ( East Thrace). The region's boundaries are based on that of the Roman Province of Thrace; the lands inhabited by the ancient Thracians extended in the north to modern-day Northern Bulgaria and Romania and to the west into the region of Macedonia. Etymology The word ''Thrace'' was first used by the Greeks when referring to the Thracian tribes, from ancient Greek Thrake (Θρᾴκη), descending from ''Thrāix'' (Θρᾷξ). It referred originally to the Thracians, an ancient people inhabiting Southeast Europe. The name ''Europe'' first referred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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