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Serbia
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Serbia, officially the Republic of Serbia, is a sovereign state situated at the crossroads of Central and Southeast Europe, covering the southern part of the Pannonian Plain and the central Balkans. Relative to its territory, it is a diverse country distinguished by a transitional character, situated along cultural, geographic, climatic. Serbia numbers around 7 million residents, and its capital, Belgrade, following the Slavic migrations to the Balkans from the 6th century onwards, Serbs established several states in the early Middle Ages. The Serbian Kingdom obtained recognition by Rome and the Byzantine Empire in 1217, in the early 19th century, the Serbian Revolution established the nation-state as the regions first constitutional monarchy, which subsequently expanded its territory. During the breakup of Yugoslavia, Serbia formed a union with Montenegro which dissolved peacefully in 2006, in 2008 the parliament of the province of Kosovo unilaterally declared independence, with mixed responses from the international community. Serbia is a member of organizations such as the UN, CoE, OSCE, PfP, BSEC. An EU membership candidate since 2012, Serbia has been negotiating its EU accession since January 2014, the country is acceding to the WTO and is a militarily neutral state. Serbia is an income economy with dominant service sector, followed by the industrial sector. The country ranks high on the Social Progress Index as well as the Global Peace Index, relatively high on the Human Development Index, located at the crossroads between Central and Southern Europe, Serbia is found in the Balkan peninsula and the Pannonian Plain. Serbia lies between latitudes 41° and 47° N, and longitudes 18° and 23° E. The country covers a total of 88,361 km2, which places it at 113th place in the world, with Kosovo excluded, the area is 77,474 km2. Its total border length amounts to 2,027 km, all of Kosovos border with Albania, Macedonia and Montenegro are under control of the Kosovo border police. The Pannonian Plain covers the third of the country while the easternmost tip of Serbia extends into the Wallachian Plain. The terrain of the part of the country, with the region of Šumadija at its heart. Mountains dominate the third of Serbia. Dinaric Alps stretch in the west and the southwest, following the flow of the rivers Drina, the Carpathian Mountains and Balkan Mountains stretch in a north–south direction in eastern Serbia. Ancient mountains in the southeast corner of the country belong to the Rilo-Rhodope Mountain system, elevation ranges from the Midžor peak of the Balkan Mountains at 2,169 metres to the lowest point of just 17 metres near the Danube river at Prahovo. The largest lake is Đerdap Lake and the longest river passing through Serbia is the Danube, the climate of Serbia is under the influences of the landmass of Eurasia and the Atlantic Ocean and Mediterranean Sea
2.
Hoodoo (geology)
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A hoodoo is a tall, thin spire of rock that protrudes from the bottom of an arid drainage basin or badland. Hoodoos, which may range from 1.5 to 45 metres, typically consist of soft rock topped by harder. They generally form within sedimentary rock and volcanic rock formations, Hoodoos are found mainly in the desert in dry, hot areas. In common usage, the difference between hoodoos and pinnacles is that hoodoos have a variable thickness often described as having a totem pole-shaped body, a spire, on the other hand, has a smoother profile or uniform thickness that tapers from the ground upward. An example of a spire, as an earth pyramid, is found at Aultderg Burn, near Fochabers. Hoodoos range in size from the height of a human to heights exceeding a 10-story building. Hoodoo shapes are affected by the patterns of alternating hard. Minerals deposited within different rock types cause hoodoos to have different colors throughout their height, Hoodoos are commonly found in the High Plateaus region of the Colorado Plateau and in the Badlands regions of the Northern Great Plains. While hoodoos are scattered throughout these areas, nowhere in the world are they as abundant as in the section of Bryce Canyon National Park. They are also very prominent a few hundred miles away at Goblin Valley State Park on the side of the San Rafael Swell. Hoodoos are a tourist attraction in the Cappadocia region of Turkey and these rock formations were depicted on the reverse of the Turkish 50 new lira banknote of 2005–2009. Đavolja Varoš hoodoos in Serbia feature 202 exotic formations described as earth pyramids or towers, since 1959, Đavolja Varoš has been protected by the state. It was also a nominee in the New Seven Wonders of Nature campaign, the hoodoo stones on the northern coast of Taiwan are unusual for their coastal setting. The stones formed as the seabed rose rapidly out of the ocean during the Miocene epoch, efforts have been made to slow the erosion in the case of iconic specimens in Wanli. Hoodoos in Drumheller, Alberta, are a feature that continues to attract thousands of visitors each year. The sediments comprising these hoodoos formed between 70 and 75 million years ago during the Cretaceous Period as clay and sand sediments from the Horseshoe Canyon Formation were deposited. In glaciated mountainous valleys the soft eroded material may be glacial till with the protective capstones being large boulders in the till, over time, cracks in the resistant layer allow the much softer rock beneath to be eroded and washed away. Hoodoos form where a small cap of the resistant layer remains, further erosion of the soft layer causes the cap to be undercut, eventually falling off, and the remaining cone is then quickly eroded
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Erosion
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In earth science, erosion is the action of surface processes that remove soil, rock, or dissolved material from one location on the Earths crust, then transport it away to another location. Eroded sediment or solutes may be transported just a few millimetres, the rates at which such processes act control how fast a surface is eroded. Feedbacks are also possible between rates of erosion and the amount of eroded material that is carried by, for example. Processes of erosion that produce sediment or solutes from a place contrast with those of deposition, while erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. At well-known agriculture sites such as the Appalachian Mountains, intensive farming practices have caused erosion up to 100x the speed of the rate of erosion in the region. Excessive erosion causes both on-site and off-site problems, on-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of bodies, as well as sediment-related damage to roads. Intensive agriculture, deforestation, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion, however, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, and the surface runoff which may result from rainfall, produces four types of soil erosion, splash erosion, sheet erosion, rill erosion. Splash erosion is generally seen as the first and least severe stage in the erosion process. In splash erosion, the impact of a falling raindrop creates a crater in the soil. The distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rate is greater than the rate at which water can infiltrate into the soil. If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope, sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes, generally, where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are typically of the order of a few centimetres or less and this means that rills exhibit hydraulic physics very different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when water accumulates and rapidly flows in narrow channels during or immediately after heavy rains or melting snow
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Andesite
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For the extinct cephalopod genus, see Andesites. Andesite is an igneous, volcanic rock, of intermediate composition. In a general sense, it is the type between basalt and dacite, and ranges from 57 to 63% silicon dioxide as illustrated in TAS diagrams. The mineral assemblage is dominated by plagioclase plus pyroxene or hornblende. Magnetite, zircon, apatite, ilmenite, biotite, and garnet are common accessory minerals, alkali feldspar may be present in minor amounts. The quartz-feldspar abundances in andesite and other rocks are illustrated in QAPF diagrams. Classification of andesites may be refined according to the most abundant phenocryst, example, hornblende-phyric andesite, if hornblende is the principal accessory mineral. Andesite can be considered as the equivalent of plutonic diorite. Characteristic of subduction zones, andesite represents the dominant rock type in island arcs, the average composition of the continental crust is andesitic. Along with basalts they are a component of the Martian crust. The name andesite is derived from the Andes mountain range, magmatism in island arc regions comes from the interplay of the subducting plate and the mantle wedge, the wedge-shaped region between the subducting and overriding plates. During subduction, the oceanic crust is submitted to increasing pressure and temperature. Hydrous minerals such as amphibole, zeolites, chlorite etc. dehydrate as they change to more stable, anhydrous forms, releasing water, fluxing water into the wedge lowers the solidus of the mantle material and causes partial melting. Due to the density of the partially molten material, it rises through the wedge until it reaches the lower boundary of the overriding plate. Basalt thus formed can contribute to the formation of andesite through fractional crystallization, partial melting of crust, or magma mixing, andesite is typically formed at convergent plate margins but may occur in other tectonic settings. Intermediate volcanic rocks are created via several processes, Fractional crystallization of a mafic parent magma and this removal can take place in a variety of ways, but most commonly this occurs by crystal settling. The first minerals to crystallize and be removed from a parent are olivines and amphiboles. These mafic minerals settle out of the magma, forming mafic cumulates, there is geophysical evidence from several arcs that large layers of mafic cumulates lie at the base of the crust
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Gully
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A gully is a landform created by running water, eroding sharply into soil, typically on a hillside. Gullies resemble large ditches or small valleys, but are metres to tens of metres in depth and width, when the gully formation is in process, the water flow rate can be substantial, causing a significant deep cutting action into soil. The earliest known usage of the term is from 1657 and it originates from the French word goulet, a diminutive form of goule which means throat. It is possible that the term was derived from a type of knife at the time, gullying or gully erosion is the process by which gullies are formed. Hillsides are more prone to gullying when they are cleared of vegetation, through deforestation, the eroded soil is easily carried by the flowing water after being dislodged from the ground, normally when rainfall falls during short, intense storms such as during thunderstorms. A gully may grow in length by means of erosion at a knick point. This erosion can result from interflow as well as surface runoff, gullies reduce the productivity of farmland where they incise into the land, and produce sediment that may clog downstream waterbodies. Because of this, much effort is invested into the study of gullies within the scope of geomorphology, in the prevention of gully erosion, the total soil loss from gully formation and subsequent downstream river sedimentation can be sizeable. Gullies can be formed or enlarged by a number of human activities, artificial gullies are formed during hydraulic mining when jets or streams of water are projected onto soft alluvial deposits to extract gold or tin ore. The remains of mining methods are very visible landform features in old goldfields such as in California. The badlands at Las Medulas for example, were created during the Roman period by hushing or hydraulic mining of the gold-rich alluvium with water supplied by numerous aqueducts tapping nearby rivers, each aqueduct produced large gullies below by erosion of the soft deposits. The effluvium was carefully washed with smaller streams of water to extract the nuggets, gullies are widespread at mid- to high latitudes on the surface of Mars, and are some of the youngest features observed on that planet, probably forming within the last few 100,000 years. Flow as springs from deeper seated liquid water aquifers in the subsurface is also a possible explanation for the formation of some Martian gullies. Arroyo Coulee Couloir Canyon Gulch Ravine Wadi Lavaka Badlands Rill Oxford English Dictionary
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Kingdom of Serbia (medieval)
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The Kingdom of Serbia, or Serbian Kingdom, was a medieval Serbian state that existed from 1217 to 1346, ruled by the Nemanjić dynasty. The Grand Principality of Serbia was elevated with the coronation of Stefan Nemanjić as king by his brother, bishop Sava, after inheriting all territories unified by their father, the kingdom was proclaimed an empire on 16 April 1346. Each province had its own nobility and institutions, and each acquired a member of the Vojislavljevići to head as Župan, the Byzantine Empire launched a campaign on Duklja between 1089 and 1091 and possibly captured Bodin. A civil war broke out in the realm among Bodins relatives, Vukan took the opportunity to assert himself and broke away, claiming the title of Grand Prince of Serbia. Rascia, Bosnia, and Zahumlje all became independent in 1091, up to this point, Duklja had been the center of the Serbian realm, as well as the main resistance to Byzantium in the Balkans. After 1091 Rascia became the most powerful of the Serbian states, under the rule of the Vukanović dynasty, Rascia also replaced Duklja as the main opponent of Byzantine rule in the 12th century. Bodins heirs were forced to recognize Byzantine overlordship, and now only the small territories of Duklja. During the reign of Vukans son Uroš I, the Byzantines invaded Duklja and sought to conquer Rascia as well, Uroš II initially fought the Byzantines, but he gave oaths of servitude to the Emperor after he was defeated in war. Stefan Nemanja was succeeded by his middle son Stefan, whilst his first-born son Vukan was given the rule of the Zeta region, Stefan Nemanjas youngest son Rastko became a monk and took the name Sava, turning all his efforts to spreading religion among his people. In Byzantium, Sava managed to secure autocephaly for the Serbian Church, in the same year Sava published the first constitution in Serbia — St. Savas Nomocanon. The Nomocanon was a compilation of Civil law, based on Roman Law and its basic purpose was to organize the functions of the young Serbian kingdom and the Serbian church. Thus the Serbs acquired both political and religious independence, the next generation of Serbian rulers — the sons of Stefan Prvovenčani, Radoslav, Vladislav, and Uroš I — marked a period of stagnation of the state structure. All three kings were more or less dependent on some of the neighbouring states — Byzantium, Bulgaria, the ties with the Hungarians played a decisive role as Uroš I was succeeded by his son Dragutin, whose wife was a Hungarian princess. Thus, some of these became part of the Serbian state for the first time. His new state was named Kingdom of Srem, in that time the name Srem was a designation for two territories, Upper Srem and Lower Srem. The Kingdom of Srem under the rule of Stefan Dragutin was actually Lower Srem, after Dragutin died in 1316, his son, king Vladislav II, became king and ruled until 1325. Under Dragutins younger brother, King Milutin, Serbia grew stronger despite having to fight wars on three different fronts. King Milutin was an apt diplomat much inclined to the use of a customary medieval diplomatic and dynastic marriages and he was married five times, with Hungarian, Bulgarian, and Byzantine princesses
7.
Spring (hydrology)
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A spring is any natural situation where water flows from an aquifer to the Earths surface. It is a component of the hydrosphere, a spring may be the result of karst topography where surface water has infiltrated the Earths surface, becoming part of the area groundwater. The groundwater then travels through a network of cracks and fissure—openings ranging from intergranular spaces to large caves, the water eventually emerges from below the surface, in the form of a karst spring. The forcing of the spring to the surface can be the result of an aquifer in which the recharge area of the spring water table rests at a higher elevation than that of the outlet. Spring water forced to the surface by elevated sources are artesian wells and this is possible even if the outlet is in the form of a 300-foot-deep cave. In this case the cave is used like a hose by the higher elevated area of groundwater to exit through the lower elevation opening. Non-artesian springs may simply flow from a higher elevation through the earth to a lower elevation, still other springs are the result of pressure from an underground source in the earth, in the form of volcanic activity. The result can be water at elevated temperature such as a hot spring, the action of the groundwater continually dissolves permeable bedrock such as limestone and dolomite, creating vast cave systems. The term seep refers to springs with small flow rates in which the water has filtered through permeable earth. Fracture springs, discharge from faults, joints, or fissures in the earth, tubular springs, in which the water flows from underground caverns. Spring discharge, or resurgence, is determined by the springs recharge basin, factors that affect the recharge include the size of the area in which groundwater is captured, the amount of precipitation, the size of capture points, and the size of the spring outlet. Water may leak into the system from many sources including permeable earth, sinkholes. In some cases entire creeks seemingly disappear as the water sinks into the ground via the stream bed, grand Gulf State Park in Missouri is an example of an entire creek vanishing into the groundwater system. The water emerges 9 miles away, forming some of the discharge of Mammoth Spring in Arkansas, human activity may also affect a springs discharge--withdrawal of groundwater reduces the water pressure in an aquifer, decreasing the volume of flow. Springs are often classified by the volume of the water they discharge, the largest springs are called first-magnitude, defined as springs that discharge water at a rate of at least 2800 liters or 100 cubic feet of water per second. The scale for spring flow is as follows, Minerals become dissolved in the water as it moves through the underground rocks and this may give the water flavor and even carbon dioxide bubbles, depending on the nature of the geology through which it passes. This is why spring water is bottled and sold as mineral water. Springs that contain significant amounts of minerals are sometimes called mineral springs, Springs that contain large amounts of dissolved sodium salts, mostly sodium carbonate, are called soda springs
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Mineral
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A mineral is a naturally occurring chemical compound, usually of crystalline form and abiogenic in origin. A mineral has one specific chemical composition, whereas a rock can be an aggregate of different minerals or mineraloids, the study of minerals is called mineralogy. There are over 5,300 known mineral species, over 5,070 of these have been approved by the International Mineralogical Association, the silicate minerals compose over 90% of the Earths crust. The diversity and abundance of species is controlled by the Earths chemistry. Silicon and oxygen constitute approximately 75% of the Earths crust, which translates directly into the predominance of silicate minerals, minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various species, changes in the temperature, pressure, or bulk composition of a rock mass cause changes in its minerals. Minerals can be described by their various properties, which are related to their chemical structure. Common distinguishing characteristics include crystal structure and habit, hardness, lustre, diaphaneity, colour, streak, tenacity, cleavage, fracture, parting, more specific tests for describing minerals include magnetism, taste or smell, radioactivity and reaction to acid. Minerals are classified by key chemical constituents, the two dominant systems are the Dana classification and the Strunz classification, the silicate class of minerals is subdivided into six subclasses by the degree of polymerization in the chemical structure. All silicate minerals have a unit of a 4− silica tetrahedron—that is, a silicon cation coordinated by four oxygen anions. These tetrahedra can be polymerized to give the subclasses, orthosilicates, disilicates, cyclosilicates, inosilicates, phyllosilicates, other important mineral groups include the native elements, sulfides, oxides, halides, carbonates, sulfates, and phosphates. The first criterion means that a mineral has to form by a natural process, stability at room temperature, in the simplest sense, is synonymous to the mineral being solid. More specifically, a compound has to be stable or metastable at 25 °C, modern advances have included extensive study of liquid crystals, which also extensively involve mineralogy. Minerals are chemical compounds, and as such they can be described by fixed or a variable formula, many mineral groups and species are composed of a solid solution, pure substances are not usually found because of contamination or chemical substitution. Finally, the requirement of an ordered atomic arrangement is usually synonymous with crystallinity, however, crystals are also periodic, an ordered atomic arrangement gives rise to a variety of macroscopic physical properties, such as crystal form, hardness, and cleavage. There have been recent proposals to amend the definition to consider biogenic or amorphous substances as minerals. The formal definition of an approved by the IMA in 1995, A mineral is an element or chemical compound that is normally crystalline. However, if geological processes were involved in the genesis of the compound, Mineral classification schemes and their definitions are evolving to match recent advances in mineral science
