Igneous rock, or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava; the magma can be crust. The melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses. Igneous rocks occur in a wide range of geological settings: shields, orogens, large igneous provinces, extended crust and oceanic crust. Igneous and metamorphic rocks make up 90–95% of the top 16 km of the Earth's crust by volume. Igneous rocks form about 15% of the Earth's current land surface. Most of the Earth's oceanic crust is made of igneous rock. Igneous rocks are geologically important because: their minerals and global chemistry give information about the composition of the mantle, from which some igneous rocks are extracted, the temperature and pressure conditions that allowed this extraction, and/or of other pre-existing rock that melted.
In terms of modes of occurrence, igneous rocks can be either extrusive. Intrusive igneous rocks make up the majority of igneous rocks and are formed from magma that cools and solidifies within the crust of a planet, surrounded by pre-existing rock; the mineral grains in such rocks can be identified with the naked eye. Intrusive rocks can be classified according to the shape and size of the intrusive body and its relation to the other formations into which it intrudes. Typical intrusive formations are batholiths, laccoliths and dikes; when the magma solidifies within the earth's crust, it cools forming coarse textured rocks, such as granite, gabbro, or diorite. The central cores of major mountain ranges consist of intrusive igneous rocks granite; when exposed by erosion, these cores may occupy huge areas of the Earth's surface. Intrusive igneous rocks that form at depth within the crust are termed plutonic rocks and are coarse-grained. Intrusive igneous rocks that form near the surface are termed subvolcanic or hypabyssal rocks and they are medium-grained.
Hypabyssal rocks are less common than plutonic or volcanic rocks and form dikes, laccoliths, lopoliths, or phacoliths. Extrusive igneous rocks known as volcanic rocks, are formed at the crust's surface as a result of the partial melting of rocks within the mantle and crust. Extrusive solidify quicker than intrusive igneous rocks, they are formed by the cooling of molten magma on the earth's surface. The magma, brought to the surface through fissures or volcanic eruptions, solidifies at a faster rate. Hence such rocks are smooth and fine-grained. Basalt is lava plateaus; some kinds of basalt solidify to form long polygonal columns. The Giant's Causeway in Antrim, Northern Ireland is an example; the molten rock, with or without suspended crystals and gas bubbles, is called magma. It rises; when magma reaches the surface from beneath water or air, it is called lava. Eruptions of volcanoes into air are termed subaerial, whereas those occurring underneath the ocean are termed submarine. Black smokers and mid-ocean ridge basalt are examples of submarine volcanic activity.
The volume of extrusive rock erupted annually by volcanoes varies with plate tectonic setting. Extrusive rock is produced in the following proportions: divergent boundary: 73% convergent boundary: 15% hotspot: 12%. Magma that erupts from a volcano behaves according to its viscosity, determined by temperature, crystal content and the amount of silica. High-temperature magma, most of, basaltic in composition, behaves in a manner similar to thick oil and, as it cools, treacle. Long, thin basalt flows with pahoehoe surfaces are common. Intermediate composition magma, such as andesite, tends to form cinder cones of intermingled ash and lava, may have a viscosity similar to thick, cold molasses or rubber when erupted. Felsic magma, such as rhyolite, is erupted at low temperature and is up to 10,000 times as viscous as basalt. Volcanoes with rhyolitic magma erupt explosively, rhyolitic lava flows are of limited extent and have steep margins, because the magma is so viscous. Felsic and intermediate magmas that erupt do so violently, with explosions driven by the release of dissolved gases—typically water vapour, but carbon dioxide.
Explosively erupted pyroclastic material is called tephra and includes tuff and ignimbrite. Fine volcanic ash is erupted and forms ash tuff deposits, which ca
Monte Scuderi is a mountain of the Peloritani range located in northeast Sicily. It boasts a flat rocky peak from where it's possible to view a superb panorama including the Strait of Messina, Mount Etna, the Aeolian Islands and the Calabria coast. A cave and ancient ruins lie on the summit and they say that a split, on that mount was created when Jesus Christ died. A popular attraction to the peak is the myth of buried treasure. Trails to its top start from the Santissima gorge near Fiumedinisi; the mountain is home to a nature reserve
Fondachelli-Fantina is a comune in the Metropolitan City of Messina, southern Italy. Situated between Novara and Francavilla di Sicilia, in the southern Peloritani mountains, it rises on an inland area and is 604 metres above sea level, around the bed of the Patrì river, the mythical Longanus river of the ancient times that arises in the valley; the community borders the municipalities of Antillo and Rodì Milici. The main mountains of his valley are Montagna Grande, Rocca Salvatesta, Montagna di Vernà, Pizzo Russa, Rocche di Durante and Pizzo Vento that form an astronomic calendar where is possible to observe the equinox, it is composed by more than 15 little villages spread on the slopes of Peloritani mountains along the Patrì river whose the most populated are Rubino, Chiesa and Fantina. It is 81 km from Catania, 87 kilometres from Messina, 129 kilometres from Syracuse, 235 kilometres from Palermo. Developed from a number of rural hamlets in the territory of Novara di Sicilia, the collective community attained autonomous status in 1950 and called itself Fondachelli-Fantina, a name derived from Fondaci and Fantinia.
It is important as one of the last Sicilian municipalities where Gallo-Sicilian survives as a spoken dialect making the town a linguistic island. The area now known as Fondachelli-Fantina always has been quite isolated. Today, the long, winding road connecting the municipality to the Ionian coast can become impassable during the winter. However, this insularity has aided in preserving the Gallo-Sicilian language, a remnant of the period during the Swabian-Norman domination when people from Northern Italy migrated to the area; the town passed into the hands of the Palizzi family, who held it until 1353, when the Gioiemi of Novara took possession. Between 1720 and 1880, the territory endured heavy mining activity; the 26 scattered mines used a great quantity of lumber, destabilized the land and degraded the mountains. Additionally, continuous flooding had devastating consequences. Major floods in 1880, 1951, 1958 and 1973 continued the territorial degradation. However, administrative autonomy from Novara di Sicilia on 20 June 1950 gave Fondachelli-Fantina legislative powers and control of public works as well as financial means to begin reforestation efforts and build roads and aqueducts.
As of March 2009, the population of Fondachelli-Fantina was 1,234 with a density of 30 inhabitants per square kilometer. Its economy is based on livestock breeding and the cultivation of grains, dried fruit, wine grapes and wood, the Maiorchino is the cheese most famous produced in the zone. On 22 June and the second Friday of July each year, the town hosts cattle fairs which are attended by exhibitors from other communities; the town has four schools: one pre-school, two primary schools, one secondary school. Community churches include Santi Angeli Custodi ES Giuseppi; the community celebrates 3 unique feast days: the Feast of the Patron of the town Santissimi Angeli Custodi on the second Sunday of July, the feast of Saint Joseph the first Sunday after mid August and the Feast of Madonna della Provvidenza on 8 September. The War Memorial is in the town centre on the Piazza santissimi Angeli Custodi, where social and sporting events are held; the Monument to Padre Pio is on via XX Giugno 1950.
Strait of Messina
The Strait of Messina, is a narrow strait between the eastern tip of Sicily and the western tip of Calabria in the south of Italy. It connects the Tyrrhenian Sea to the north with the Ionian Sea to the south, within the central Mediterranean. At its narrowest point, between Torre Faro and Villa San Giovanni, it is 3.1 km wide. At the town of Messina it is 5.1 km wide. The strait's maximum depth is about 250 m; the strait has strong tidal currents. A natural whirlpool in the northern portion of the strait has been linked to the Greek legend of Scylla and Charybdis. In some circumstances, the mirage of Fata Morgana can be observed when looking at Sicily from Calabria. With its bottleneck shape, it is a compulsory point of transit of the migration of many bird species. In 1957, a 220 kV overhead power line was built across the Strait of Messina, its pylons are among the highest in the world. This power line has since been replaced by a submarine power cable, but the pylons remain and are protected as historical monuments.
The Strait of Messina is a focal point in the migrations of birds every year, who cross the strait to reach their breeding grounds in northern Europe. Due to this form of bottleneck more than 300 species are recorded in the area, a major European hot spot for raptors, with a record of 35.000 in a spring. Among them the European honey buzzard and the marsh harrier are the most frequent, species like Bonelli's eagle and Egyptian vulture are less frequent but regular. In the coastal salt lakes of the Strait of Messina species like glossy ibis and black-winged stilt stop to rest; the site is favorable for observing storks. The Monte Dinnammare and the other Peloritani mountains overlooking the Strait are a natural theatre for birdwatching. Due to its unique hydrogeological conditions the Strait of Messina has high levels of biodiversity and multiple endemic species. In its waters there is a strong presence of deep sea fish like the Sloane's viperfish which, due to the particular and peculiar currents of the strait, are found stranded on the shore at sunrise.
The strait is an important point of migration of many species of fish in the Mediterranean Sea. A ferry service connects Messina on Sicily with the mainland at Villa San Giovanni, which lies several kilometers north of the large city of Reggio Calabria. There is a hydrofoil service between Messina and Reggio Calabria. For decades, the possibility of building a bridge across the Messina Strait has been under discussion. In 2006, under Prime Minister Romano Prodi the project was cancelled. On 6 March 2009, however, as part of a massive new public works program, Silvio Berlusconi's government announced that plans to construct the Messina Bridge had been revived, pledging €1.3 billion as a contribution to its estimated cost of €6.1 billion Some 3.3 km long and 60 m wide, the bridge would be supported by two 382 m pillars, each higher than the Empire State Building, accommodate six freeway lanes, a railway, two walkways. Supporters perceive a boost for tourism to the island. Opponents see it as an ecological disaster, a structure at risk due to strong winds and earthquakes, a boon for Sicilian and Calabrian organized crime.
Berlusconi claimed in 2009 that work would be completed by 2016 although in February 2013, the project was cancelled again. Between Scylla and Charybdis Fabio Spadi "The Bridge on the Strait of Messina:'Lowering' the Right of Innocent Passage?" International and Comparative Law Quarterly 50: 411 ff. "From Rome to Sicily: Plane or Train?" Expert Travel Advice, The New York Times, Feb. 7, 2008 The New York Times
In physical geography, a steppe is an ecoregion, in the montane grasslands and shrublands and temperate grasslands and shrublands biomes, characterized by grassland plains without trees apart from those near rivers and lakes. In South Africa, they are referred to as veld; the prairie of North America is an example of a steppe, though it is not called such. A steppe may be semi-arid or covered with grass or shrubs or both, depending on the season and latitude; the term is used to denote the climate encountered in regions too dry to support a forest but not dry enough to be a desert. The soil is of chernozem type. Steppes are characterized by a semi-arid or continental climate. Extremes can be recorded in the summer of up to 45 °C and in winter, −55 °C. Besides this huge difference between summer and winter, the differences between day and night are very great. In both the highlands of Mongolia and northern Nevada, 30 °C can be reached during the day with sub-zero °C readings at night; the mid-latitude steppes can be summarized by hot summers and cold winters, averaging 250–510 mm of precipitation per year.
Precipitation level alone is not. Two types of steppe can be recorded: Temperate steppe: the "true" steppe, found in continental areas of the world; the Eurasian Grass-Steppe of the temperate grasslands and shrublands had a role in the spread of the horse, the wheel, the Indo-European languages. The Indo-European expansion and diverse invasions of horse archer civilizations of the steppe led to, e.g. the rise of Mycenaean Greece by amalgamation of Indo-Europeans with the autochthonous pre-Greek population and its destruction during the Dorian invasion in the Late Bronze Age collapse, followed by the demise of the Achaeans, the spread of the Sea Peoples, the rise of Archaic and Classical Greece. The world's largest steppe region referred to as "the Great Steppe", is found in Eastern Europe and Central Asia, neighbouring countries stretching from Ukraine in the west through Russia, China and Uzbekistan to the Altai, Koppet Dag and Tian Shan ranges; the inner parts of Anatolia in Turkey, Central Anatolia and East Anatolia in particular and some parts of Southeast Anatolia, as well as much of Armenia and Iran are dominated by cold steppe.
The Pannonian Plain is another steppe region in eastern Europe Hungary. Another large steppe area is located in the central United States, western Canada and northern part of Mexico; the shortgrass prairie steppe is the westernmost part of the Great Plains region. The Channeled Scablands in Southern British Columbia and Washington State is an example of a steppe region in North America outside of the Great Plains. In South America, cold steppe can be found in Patagonia and much of the high elevation regions east of the southern Andes. Small steppe areas can be found in the interior of the South Island of New Zealand. In Europe, some Mediterranean areas have a steppe-like vegetation, such as central Sicily in Italy, southern Portugal, parts of Greece in the southern Athens area, central-eastern Spain the southeastern coast, places cut off from adequate moisture due to rain shadow effects such as Zaragoza. In Asia, a subtropical steppe can be found in semi-arid lands that fringe the Thar Desert of the Indian subcontinent and the Badia of the Arabian peninsula.
In Australia, "subtropical steppe" can be found in a belt surrounding the most severe deserts of the continent and around the Musgrave Ranges. In North America this environment is typical of transition areas between zones with a Mediterranean climate and true deserts, such as Reno, the inner part of California, much of western Texas and adjacent areas in Mexico. Ecology and Conservation of Steppe-land Birds by Manuel B. Morales, Santi Mañosa, Jordi Camprodón, Gerard Bota. International Symposium on Ecology and Conservation of steppe-land birds. Lleida, Spain. December 2004. ISBN 84-87334-99-7 "The Steppes". Barramedasoft.com.ar. 1998–2008. Retrieved 2008-04-04
Sandstone is a clastic sedimentary rock composed of sand-sized mineral particles or rock fragments. Most sandstone is composed of quartz or feldspar because they are the most resistant minerals to weathering processes at the Earth's surface, as seen in Bowen's reaction series. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, yellow, grey, pink and black. Since sandstone beds form visible cliffs and other topographic features, certain colors of sandstone have been identified with certain regions. Rock formations that are composed of sandstone allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Fine-grained aquifers, such as sandstones, are better able to filter out pollutants from the surface than are rocks with cracks and crevices, such as limestone or other rocks fractured by seismic activity. Quartz-bearing sandstone can be changed into quartzite through metamorphism related to tectonic compression within orogenic belts.
Sandstones are clastic in origin. They are formed from cemented grains that may either be fragments of a pre-existing rock or be mono-minerallic crystals; the cements binding these grains together are calcite and silica. Grain sizes in sands are defined within the range of 0.0625 mm to 2 mm. Clays and sediments with smaller grain sizes not visible with the naked eye, including siltstones and shales, are called argillaceous sediments; the formation of sandstone involves two principal stages. First, a layer or layers of sand accumulates as the result of sedimentation, either from water or from air. Sedimentation occurs by the sand settling out from suspension. Once it has accumulated, the sand becomes sandstone when it is compacted by the pressure of overlying deposits and cemented by the precipitation of minerals within the pore spaces between sand grains; the most common cementing materials are silica and calcium carbonate, which are derived either from dissolution or from alteration of the sand after it was buried.
Colors will be tan or yellow. A predominant additional colourant in the southwestern United States is iron oxide, which imparts reddish tints ranging from pink to dark red, with additional manganese imparting a purplish hue. Red sandstones are seen in the Southwest and West of Britain, as well as central Europe and Mongolia; the regularity of the latter favours use as a source for masonry, either as a primary building material or as a facing stone, over other forms of construction. The environment where it is deposited is crucial in determining the characteristics of the resulting sandstone, which, in finer detail, include its grain size and composition and, in more general detail, include the rock geometry and sedimentary structures. Principal environments of deposition may be split between terrestrial and marine, as illustrated by the following broad groupings: Terrestrial environmentsRivers Alluvial fans Glacial outwash Lakes Deserts Marine environmentsDeltas Beach and shoreface sands Tidal flats Offshore bars and sand waves Storm deposits Turbidites Framework grains are sand-sized detrital fragments that make up the bulk of a sandstone.
These grains can be classified into several different categories based on their mineral composition: Quartz framework grains are the dominant minerals in most clastic sedimentary rocks. These physical properties allow the quartz grains to survive multiple recycling events, while allowing the grains to display some degree of rounding. Quartz grains evolve from plutonic rock, which are felsic in origin and from older sandstones that have been recycled. Feldspathic framework grains are the second most abundant mineral in sandstones. Feldspar can be divided into two smaller subdivisions: plagioclase feldspars; the different types of feldspar can be distinguished under a petrographic microscope. Below is a description of the different types of feldspar. Alkali feldspar is a group of minerals in which the chemical composition of the mineral can range from KAlSi3O8 to NaAlSi3O8, this represents a complete solid solution. Plagioclase feldspar is a complex group of solid solution minerals that range in composition from NaAlSi3O8 to CaAl2Si2O8.
Lithic framework grains are pieces of ancient source rock that have yet to weather away to individual mineral grains, called lithic fragments or clasts. Lithic fragments can be any fine-grained or coarse-grained igneous, metamorphic, or sedimentary rock, although the most common lithic fragments found in sedimentary rocks are clasts of volcanic rocks. Accessory minerals are all other mineral grains in a sandstone. Common accessory minerals include micas, olivine and corundum. Many of these accessory grains are more dense than the silicates that
The Monte Dinnammare is the mountain that dominates the city of Messina on the eastern edge of Sicily, belonging to the Peloritani range. From its top it is possible to enjoy the panorama of the two seas and Tyrrhenian, the Aeolian Islands, the Strait of Messina and Mount Etna; the Madonna of Dinnammare Sanctuary is located on its top and every third day of August, in the evening, a traditional procession starts from the village of Larderia in Messina to arrive at sunrise on the following day at the Sanctuary to celebrate the Madonna of Dinnammare with a mass. A few metres below the top of the mount an ancient path named Dorsale dei Peloritani starts, going through all the ridge line of the Peloritani mountains; the mount is a natural theatre for birdwatching of the birds that cross the Strait of Messina every year. Twenty kilometeres is the distance between the port of Messina and its top