1.
Etruscan architecture
–
Etruscan architecture was created between about 700 BC and 200 BC, when the expanding civilization of ancient Rome finally absorbed Etruscan civilization. The Etruscans were considerable builders in stone, wood and other materials of temples, houses, tombs and city walls, as well as bridges, from about 630 BC, Etruscan architecture was heavily influenced by Greek architecture, which was itself developing through the same period. In turn it influenced Roman architecture, which in its early centuries can be considered as just a variation of Etruscan architecture. But increasingly, from about 200 BC, the Romans looked directly to Greece for their styling, apart from the podia of temples and some house foundations, only the walls and rock-cut tombs were mainly in stone, and have therefore often largely survived. Usually, only the podium or base platform used stone, with the parts of wood and mud-brick. However, there is evidence for the portico columns sometimes using stone and this has left much about Etruscan temples uncertain. The only written account of significance on their architecture is by Vitruvius, many aspects of his description fit what archaeologists can demonstrate, but others do not. It is in any case clear that Etruscan temples could take a number of forms, nonetheless Vitruvius remains the inevitable starting point for a description, and a contrast of Etruscan temples with their Greek and Roman equivalents. There are also a few temples in pottery, and depictions on tombs or vases. Vitruvius specifies three doors and three cellae, one for each of the main Etruscan deities, but archaeological remains do not suggest this was normal, though it is found. Roman sources were in the habit of ascribing to the Etruscans a taste for triads in things such as city planning, the orientation of the temple is not consistent, and may have been determined by a priest watching the flight of birds at the time of foundation. The exteriors of both Greek and Roman temples were highly decorated and colourful, especially in the entablature and roofs. When wood was used for columns, the bases and capitals were often encased in painted terracotta, the Apollo of Veii was part of an acroterion group. The groups from Luni and Talamone are among the most impressive, the podia are also usually higher, and can only be entered at a section of the front, just presenting a blank platform wall elsewhere. There may only be columns at the front portico, in Etruscan temples, more than Roman ones, the portico is deep, often representing, as Vitruvius recommends, half of the area under the roof, with multiple rows of columns. Fluted Tuscan/Doric columns can also be found, against Greek and later Roman conventions, Etruscan architecture shared with Ancient Egyptian architecture the use of large cavetto mouldings as a cornice, though not on the same massive scale. The cavetto took the place of the Greek cymatium in many temples, often painted with vertical tongue patterns and its first version was traditionally dedicated in 509 BC, but in 83 BC it was destroyed by fire, and the rebuilt Greek-style temple completed in 69 BC. But for the building they were summoned from Greece
2.
Cerveteri
–
Cerveteri is a town and comune of northern Lazio in the region of the Metropolitan City of Rome. It is famous for the site of the ancient Etruscan city which was one of the most important Etruscan cities with a more than 15 times larger than todays town. Caere was one of the city-states of the Etruscan League and at its height, around 600 BC, the ancient city was situated about 7 km from the sea, a location which made it a wealthy trading town derived originally from the iron ore mines in the Tolfa hills. It had three sea ports including Pyrgi, connected to Caere by a road approximately 13 km long and 10 metres wide, little is known of the ancient city although six temples are known from various sources. Two of them have been excavated, one of Hera, the other in the north of the city, parts of the city walls are still visible today and excavations opened up a theatre. One famous and important work of art is the Sarcophagus of the Spouses, the most famous attraction of Cerveteri is the Necropoli della Banditaccia, which has been declared by UNESCO a World Heritage Site together with the necropolis in Tarquinia. It covers an area of 400 hectares, of which 10 hectares can be visited and it is the largest ancient necropolis in the Mediterranean area. The name Banditaccia comes from the leasing of areas of land to the Cerveteri population by the local landowners, the tombs date from the 9th century BC to the later Etruscan period. The earliest tombs are in the shape of a pit, in which the ashes of the dead were housed, the visitable area contains two such roads, the Via dei Monti Ceriti and the Via dei Monti della Tolfa. Modern knowledge of Etruscan daily life is dependent on the numerous decorative details. The most recent tombs date from the 3rd century BC, some of them are marked by external cippi, which are cylindrical for men, and in the shape of a small house for women. A large number of finds excavated at Cerveteri are in the National Etruscan Museum, Rome, with others in the Vatican Museums, others, mainly pottery, are in the Archaeological Museum at Cerveteri itself. The Rocca Church of Santa Maria Maggiore, including a medieval section reachable from the 1950s addition through a triumphal arch, palazzo Ruspoli, rebuilt as baronal palace by the Orsini in 1533. The portico and the loggia on the façade are from the 17th century and it is connected to Santa Maria Maggiore through a passetto, built in 1760. The small church of SantAntonio Abate, with a 1472 fresco by Lorenzo da Viterbo, the medieval burgh of Ceri Castle of Cerenova Around the city of Cerveteri is an Italian DOC wine region that produces red and white blended wines. The red wines are blends of 60% Sangiovese and Montepulciano, 25% Cesanese and up to 30% of Canaiolo, Carignan, the grapes are limited to a harvest yield of 15 tonnes/ha and the final wine must have a minimum alcohol level of 11%. The white wines are composed of a blend of 50% Trebbiano Romagnolo and Giallo, a maximum of 35% Malvasia di Candia. The grapes are limited to a harvest yield of 14 tonnes/ha, for the ancient bishopric that originally had its seat in Cerveteri and is now a titular see, see Caere
3.
Bandelier National Monument
–
Bandelier National Monument is a 33, 677-acre United States National Monument near Los Alamos in Sandoval and Los Alamos Counties, New Mexico. The monument preserves the homes and territory of the Ancestral Puebloans of an era in the Southwest. Most of the structures date to two eras, dating between 1150 and 1600 AD. The Monument is 50 square miles of the Pajarito Plateau, on the slopes of the Jemez Volcanic field in the Jemez Mountains, there are three miles of road, and more than 70 miles of hiking trails. The Monument protects Ancestral Pueblo archeological sites, a diverse and scenic landscape, the park infrastructure was developed in the 1930s by crews of the Civilian Conservation Corps, and are a National Historic Landmark for their well-preserved architecture. The National Park Service co-operates with surrounding pueblos, other federal agencies, the monument received 193,914 visitors in 2011. In October 1976, roughly seventy percent of the monument,23,267 acres, was included within the National Wilderness Preservation System, the parks elevations range from about 5,000 feet at the Rio Grande to over 10,200 feet at the summit of Cerro Grande. The Valles Caldera National Preserve adjoins the monument on the north and west, much of the area was covered with volcanic ash from an eruption of the Valles Caldera volcano 1.14 million years ago. The tuff overlays shales and sandstones deposited during the Permian Period, the volcanic outflow varied in hardness, the Ancestral Pueblo People broke up the firmer materials to use as bricks, while they carved out dwellings from the softer material. Human presence in the area has been dated to over 10,000 years before present, permanent settlements by ancestors of the Puebloan peoples have been dated to 1150 CE, these settlers had moved closer to the Rio Grande by 1550. Spanish colonial settlers arrived in the 18th century, the Pueblo Jose Montoya brought Adolph Bandelier to visit the area in 1880. Looking over the dwellings, Bandelier said, It is the grandest thing I ever saw. Based on documentation and research by Bandelier, there was support for preserving the area, supporting infrastructure, including a lodge, was built during the 1920s and 1930s. This group of 31 buildings illustrates the principles of National Park Service Rustic architecture, being based on local materials. It has been designated as a National Landmark District, Frijoles Canyon contains a number of ancestral pueblo homes, kivas, rock paintings, and petroglyphs. Some of the dwellings were rock structures built on the floor, others were cavates produced by voids in the volcanic tuff of the canyon wall. A1. 2-mile, predominantly paved, Main Loop Trail from the visitor center affords access to these features. A trail extending beyond this leads to Alcove House, a shelter cave produced by erosion of the soft rock and containing a small
4.
New Mexico
–
New Mexico is a state located in the southwestern region of the United States of America. It was admitted to the Union as the 47th state on January 6,1912 and it is usually considered one of the Mountain States. New Mexico is fifth by area, the 36th-most populous, inhabited by Native Americans for thousands of years before European exploration, New Mexico was colonized by the Spanish in 1598 Imperial Spanish viceroyalty of New Spain. Later, it was part of independent Mexico before becoming a U. S. territory and eventually a U. S. state as a result of the Mexican–American War. Among U. S. states, New Mexico has the highest percentage of Hispanics, the major Native American nations in the state are Navajo, Pueblo, and Apache peoples. The demography and culture of the state are shaped by these strong Hispanic and Native American influences and its scarlet and gold colors are taken from the royal standards of Spain, along with the ancient sun symbol of the Zia, a Pueblo-related tribe. New Mexico, or Nuevo México in Spanish, is incorrectly believed to have taken its name from the nation of Mexico. The name simply stuck, even though the area had no connection to Mexico or the Mexica Indian tribes, Mexico, formerly a part of New Spain, adopted its name centuries later in 1821, after winning independence from Spanish rule. New Mexico was a part of the independent Mexican Empire and Federal Republic of Mexico for 27 years,1821 through 1848, New Mexico and Mexico developed as neighboring Spanish-speaking communities under Spanish rule, with relatively independent histories. The states total area is 121,412 square miles, the eastern border of New Mexico lies along 103° W longitude with the state of Oklahoma, and 2.2 miles west of 103° W longitude with Texas. On the southern border, Texas makes up the eastern two-thirds, while the Mexican states of Chihuahua and Sonora make up the western third, the western border with Arizona runs along the 109°03 W longitude. The southwestern corner of the state is known as the Bootheel, the 37° N latitude parallel forms the northern boundary with Colorado. The states New Mexico, Colorado, Arizona, and Utah come together at the Four Corners in the corner of New Mexico. New Mexico, although a state, has very little water. Its surface water area is about 250 square miles, the New Mexican landscape ranges from wide, rose-colored deserts to broken mesas to high, snow-capped peaks. Despite New Mexicos arid image, heavily forested mountain wildernesses cover a significant portion of the state, the Sangre de Cristo Mountains, the southernmost part of the Rocky Mountains, run roughly north-south along the east side of the Rio Grande in the rugged, pastoral north. The most important of New Mexicos rivers are the Rio Grande, Pecos, Canadian, San Juan, the Rio Grande is tied for the fourth-longest river in the United States. Tourists visiting these sites bring significant money to the state, other areas of geographical and scenic interest include Kasha-Katuwe Tent Rocks National Monument and the Gila Wilderness in the southwest of the state
5.
Italian language
–
By most measures, Italian, together with Sardinian, is the closest to Latin of the Romance languages. Italian is a language in Italy, Switzerland, San Marino, Vatican City. Italian is spoken by minorities in places such as France, Montenegro, Bosnia & Herzegovina, Crimea and Tunisia and by large expatriate communities in the Americas. Many speakers are native bilinguals of both standardized Italian and other regional languages, Italian is the fourth most studied language in the world. Italian is a major European language, being one of the languages of the Organisation for Security and Cooperation in Europe. It is the third most widely spoken first language in the European Union with 65 million native speakers, including Italian speakers in non-EU European countries and on other continents, the total number of speakers is around 85 million. Italian is the working language of the Holy See, serving as the lingua franca in the Roman Catholic hierarchy as well as the official language of the Sovereign Military Order of Malta. Italian is known as the language of music because of its use in musical terminology and its influence is also widespread in the arts and in the luxury goods market. Italian has been reported as the fourth or fifth most frequently taught foreign language in the world, Italian was adopted by the state after the Unification of Italy, having previously been a literary language based on Tuscan as spoken mostly by the upper class of Florentine society. Its development was influenced by other Italian languages and to some minor extent. Its vowels are the second-closest to Latin after Sardinian, unlike most other Romance languages, Italian retains Latins contrast between short and long consonants. As in most Romance languages, stress is distinctive, however, Italian as a language used in Italy and some surrounding regions has a longer history. What would come to be thought of as Italian was first formalized in the early 14th century through the works of Tuscan writer Dante Alighieri, written in his native Florentine. Dante is still credited with standardizing the Italian language, and thus the dialect of Florence became the basis for what would become the language of Italy. Italian was also one of the recognised languages in the Austro-Hungarian Empire. Italy has always had a dialect for each city, because the cities. Those dialects now have considerable variety, as Tuscan-derived Italian came to be used throughout Italy, features of local speech were naturally adopted, producing various versions of Regional Italian. Even in the case of Northern Italian languages, however, scholars are not to overstate the effects of outsiders on the natural indigenous developments of the languages
6.
Rock (geology)
–
Rock or stone is a natural substance, a solid aggregate of one or more minerals or mineraloids. For example, granite, a rock, is a combination of the minerals quartz, feldspar. The Earths outer solid layer, the lithosphere, is made of rock, rock has been used by mankind throughout history. The minerals and metals found in rocks have been essential to human civilization, three major groups of rocks are defined, igneous, sedimentary, and metamorphic. The scientific study of rocks is called petrology, which is a component of geology. At a granular level, rocks are composed of grains of minerals, the aggregate minerals forming the rock are held together by chemical bonds. The types and abundance of minerals in a rock are determined by the manner in which the rock was formed, many rocks contain silica, a compound of silicon and oxygen that forms 74. 3% of the Earths crust. This material forms crystals with other compounds in the rock, the proportion of silica in rocks and minerals is a major factor in determining their name and properties. Rocks are geologically classified according to such as mineral and chemical composition, permeability, the texture of the constituent particles. These physical properties are the end result of the processes that formed the rocks, over the course of time, rocks can transform from one type into another, as described by the geological model called the rock cycle. These events produce three general classes of rock, igneous, sedimentary, and metamorphic, the three classes of rocks are subdivided into many groups. However, there are no hard and fast boundaries between allied rocks, hence the definitions adopted in establishing rock nomenclature merely correspond to more or less arbitrary selected points in a continuously graduated series. Igneous rock forms through the cooling and solidification of magma or lava and this magma can be derived from partial melts of pre-existing rocks in either a planets mantle or crust. Typically, the melting of rocks is caused by one or more of three processes, an increase in temperature, a decrease in pressure, or a change in composition, igneous rocks are divided into two main categories, plutonic rock and volcanic. Plutonic or intrusive rocks result when magma cools and crystallizes slowly within the Earths crust, a common example of this type is granite. Volcanic or extrusive rocks result from magma reaching the surface either as lava or fragmental ejecta, the chemical abundance and the rate of cooling of magma typically forms a sequence known as Bowens reaction series. Most major igneous rocks are found along this scale, about 64. 7% of the Earths crust by volume consists of igneous rocks, making it the most plentiful category. Of these, 66% are basalts and gabbros, 16% are granite, only 0. 6% are syenites and 0. 3% peridotites and dunites
7.
Volcanic ash
–
Volcanic ash consists of fragments of pulverized rock, minerals and volcanic glass, created during volcanic eruptions and measuring less than 2 mm in diameter. The term volcanic ash is often loosely used to refer to all explosive eruption products. Volcanic ash is formed during volcanic eruptions when dissolved gases in magma expand. The force of the escaping gas shatters the magma and propels it into the atmosphere where it solidifies into fragments of volcanic rock and glass. Ash is also produced when magma comes into contact with water during phreatomagmatic eruptions, once in the air, ash is transported by wind up to thousands of kilometers away. Volcanic ash is formed during volcanic eruptions, phreatomagmatic eruptions. Explosive eruptions occur when magma decompresses as it rises, allowing dissolved volatiles to exsolve into gas bubbles, as more bubbles nucleate a foam is produced, which decreases the density of the magma, accelerating it up the conduit. Fragmentation occurs when bubbles occupy ~70-80 vol% of the erupting mixture, when fragmentation occurs, violently expanding bubbles tear the magma apart into fragments which are ejected into the atmosphere where they solidify into ash particles. Fragmentation is an efficient process of ash formation and is capable of generating very fine ash even without the addition of water. Volcanic ash is produced during phreatomagmatic eruptions. During these eruptions fragmentation occurs when magma comes into contact with bodies of water groundwater, as the magma, which is significantly hotter than the boiling point of water, comes into contact with water an insulating vapor film forms. Eventually this vapor film will collapse leading to direct coupling of the cold water and this increases the heat transfer which leads to the rapid expansion of water and fragmentation of the magma into small particles which are subsequently ejected from the volcanic vent. Fragmentation causes an increase in area between magma and water creating a feedback mechanism, leading to further fragmentation and production of fine ash particles. Pyroclastic density currents can also produce ash particles and these are typically produced by lava dome collapse or collapse of the eruption column. Within pyroclastic density currents particle abrasion occurs as particles interact with each resulting in a reduction in grain size. In addition, ash can be produced during secondary fragmentation of pumice fragments and these processes produce large quantities of very fine grained ash which is removed from pyroclastic density currents in co-ignimbrite ash plumes. Physical and chemical characteristics of volcanic ash are primarily controlled by the style of volcanic eruption, another parameter controlling the amount of ash produced is the duration of the eruption, the longer the eruption is sustained, the more ash will be produced. The types of minerals present in volcanic ash are dependent on the chemistry of the magma from which it erupted, low energy eruptions of basalt produce a characteristically dark coloured ash containing ~45 - 55% silica that is generally rich in iron and magnesium
8.
Volcano
–
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Earths volcanoes occur because its crust is broken into 17 major, therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. This type of volcanism falls under the umbrella of plate hypothesis volcanism, Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called hotspots, for example Hawaii, are postulated to arise from upwelling diapirs with magma from the boundary,3,000 km deep in the Earth. Volcanoes are usually not created where two plates slide past one another. Erupting volcanoes can pose hazards, not only in the immediate vicinity of the eruption. Historically, so-called volcanic winters have caused catastrophic famines, the word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled vulcanology, at the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock. Most divergent plate boundaries are at the bottom of the oceans, therefore, most volcanic activity is submarine, black smokers are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed, for example, subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the plate subducts, or submerges under the continental plate forming a deep ocean trench just offshore. In a process called flux melting, water released from the subducting plate lowers the temperature of the overlying mantle wedge. This magma tends to be very viscous due to its high content, so it often does not reach the surface. When it does reach the surface, a volcano is formed, typical examples of this kind of volcano are Mount Etna and the volcanoes in the Pacific Ring of Fire. Because tectonic plates move across them, each volcano becomes dormant and is eventually re-formed as the plate advances over the postulated plume and this theory is currently under criticism, however. The most common perception of a volcano is of a mountain, spewing lava and poisonous gases from a crater at its summit, however. The features of volcanoes are more complicated and their structure. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have features such as massive plateaus
9.
Types of volcanic eruptions
–
Several types of volcanic eruptions—during which lava, tephra, and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed, some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series. There are three different types of eruptions, the most well-observed are magmatic eruptions, which involve the decompression of gas within magma that propels it forward. Phreatomagmatic eruptions are another type of eruption, driven by the compression of gas within magma. Within these wide-defining eruptive types are several subtypes, the weakest are Hawaiian and submarine, then Strombolian, followed by Vulcanian and Surtseyan. The stronger eruptive types are Pelean eruptions, followed by Plinian eruptions, subglacial and phreatic eruptions are defined by their eruptive mechanism, and vary in strength. An important measure of strength is Volcanic Explosivity Index, an order of magnitude scale ranging from 0 to 8 that often correlates to eruptive types. Explosive eruptions are characterized by gas-driven explosions that propels magma and tephra, effusive eruptions, meanwhile, are characterized by the outpouring of lava without significant explosive eruption. Volcanic eruptions vary widely in strength, on the one extreme there are effusive Hawaiian eruptions, which are characterized by lava fountains and fluid lava flows, which are typically not very dangerous. On the other extreme, Plinian eruptions are large, violent, volcanoes are not bound to one eruptive style, and frequently display many different types, both passive and explosive, even the span of a single eruptive cycle. Volcanoes do not always erupt vertically from a crater near their peak. Some volcanoes exhibit lateral and fissure eruptions, notably, many Hawaiian eruptions start from rift zones, and some of the strongest Surtseyan eruptions develop along fracture zones. Scientists believed that pulses of magma mixed together in the chamber before climbing upward—a process estimated to several thousands of years. But Columbia University volcanologists found that the eruption of Costa Rica’s Irazú Volcano in 1963 was likely triggered by magma that took a route from the mantle over just a few months. The volcanic explosivity index is a scale, from 0 to 8 and it is used by the Smithsonian Institutions Global Volcanism Program in assessing the impact of historic and prehistoric lava flows. It operates in a way similar to the Richter scale for earthquakes, the vast majority of volcanic eruptions are of VEIs between 0 and 2. Volcanic eruptions by VEI index Magmatic eruptions produce juvenile clasts during explosive decompression from gas release, Hawaiian eruptions are a type of volcanic eruption, named after the Hawaiian volcanoes with which this eruptive type is hallmark. Hawaiian eruptions are the calmest types of events, characterized by the effusive eruption of very fluid basalt-type lavas with low gaseous content
10.
Consolidation (soil)
–
Consolidation is a process by which soils decrease in volume. According to Karl von Terzaghi consolidation is any process which involves a decrease in water content of saturated soil without replacement of water by air, in general it is the process in which reduction in volume takes place by expulsion of water under long term static loads. It occurs when stress is applied to a soil causes the soil particles to pack together more tightly. When this occurs in a soil that is saturated with water, water will be squeezed out of the soil, the magnitude of consolidation can be predicted by many different methods. In the Classical Method, developed by Terzaghi, soils are tested with an oedometer test to determine their compression index and this can be used to predict the amount of consolidation. When stress is removed from a soil, the soil will rebound. If the stress is reapplied, the soil will consolidate again along a recompression curve, the soil which had its load removed is considered to be overconsolidated. This is the case for soils which have previously had glaciers on them, the highest stress that it has been subjected to is termed the preconsolidation stress. The over consolidation ratio or OCR is defined as the highest stress experienced divided by the current stress, a soil which is currently experiencing its highest stress is said to be normally consolidated and to have an OCR of one. A soil could be considered underconsolidated immediately after a new load is applied, the process of consolidation is often explained with an idealized system composed of a spring, a container with a hole in its cover, and water. In this system, the spring represents the compressibility or the structure of the soil itself, the container is completely filled with water, and the hole is closed. A load is applied onto the cover, while the hole is still unopened, at this stage, only the water resists the applied load. As soon as the hole is opened, water starts to drain out through the hole, after some time, the drainage of water no longer occurs. Now, the spring alone resists the applied load and this method assumes consolidation occurs in only one-dimension. Laboratory data is used to construct a plot of strain or void ratio versus effective stress where the stress axis is on a logarithmic scale. The plots slope is the index or recompression index. The equation for consolidation settlement of a consolidated soil can then be determined to be. E0 is the void ratio
11.
Tufa
–
Tufa is a variety of limestone formed when carbonate minerals precipitate out of ambient temperature water. Geothermally heated hot springs sometimes produce similar carbonate deposits known as travertine, Tufa is sometimes referred to as travertine. It should not be confused with hot spring travertine, however, Mono Lakes tufa is thermogene, according to Pentecost. Tufa, which is calcareous, should not be confused with tuff, modern and fossil tufa deposits abound with wetland plants, as such many tufa deposits are characterised by their large macrobiological component and are highly porous. Tufa forms either in fluvial channels or in lacustrine settings, ford and Pedley provide a review of tufa systems worldwide. Deposits can be classified by their depositional environment, Pedley provides an extensive classification system, which includes the following classes of fluvial tufa, Spring – Deposits form on emergence from a spring/seep. Barrages often contain a significant detrital component, composed of organic material, lacustrine tufas are generally formed at the periphery of lakes and build up phytoherms and stromatolites. Oncoids are also common in these environments, while fluvial and lacustrine systems make up the bulk of tufa systems worldwide, there are several other important tufa environments. Although sometimes regarded as a distinct carbonate deposit, calcareous sinter formed from ambient temperature water can be considered a sub-type of tufa, calcareous speleothems may be regarded as a form of calcareous sinter. They lack any significant macrophyte component due to the absence of light, Tufa columns are an unusual form of tufa typically associated with saline lakes. They are distinct from most tufa deposits in that lack any significant macrophyte component. Some tufa columns may form from hot-springs and therefore actually be a form of travertine. It is generally thought that such features form from CaCO3 precipitated when carbonate rich source waters emerge into alkaline soda lakes and they have also been found in marine settings. Tufa deposits form an important habitat for a diverse flora, bryophytes and diatoms are well represented. The porosity of the deposits creates a wet habitat ideal for these plants, modern tufa is formed from alkaline waters, supersaturated with calcite. On emergence, waters degas CO2 due to the lower atmospheric pCO2, since carbonate solubility decreases with increased pH, precipitation is induced. Supersaturation may be enhanced by leading to a reduction in pCO2, for example increased air-water interactions at waterfalls may be important. Recently it has demonstrated that microbially induced precipitation may be more important than physico-chemical precipitation
12.
Easter Island
–
Easter Island is a Chilean island in the southeastern Pacific Ocean, at the southeasternmost point of the Polynesian Triangle. Easter Island is famous for its 887 extant monumental statues, called moai, in 1995, UNESCO named Easter Island a World Heritage Site, with much of the island protected within Rapa Nui National Park. However, human activity, the introduction of the Polynesian rat, by the time of European arrival in 1722, the islands population had dropped to 2, 000–3,000 from an estimated high of approximately 15,000 just a century earlier. European diseases and Peruvian slave raiding in the 1860s further reduced the Rapa Nui population, Easter Island is one of the most remote inhabited islands in the world. Easter Island is a territory of Chile that was annexed in 1888. Administratively, it belongs to the Valparaíso Region, and, more specifically, according to the 2012 Chilean census, the island has about 5,800 residents, of whom some 60 percent are descendants of the aboriginal Rapa Nui. Easter Island is considered part of Insular Chile, the islands official Spanish name, Isla de Pascua, also means Easter Island. However, Norwegian ethnographer Thor Heyerdahl argued that Rapa was the name of Easter Island. William Churchill inquired about the phrase and was told there were three te pito o te henua, these being the three capes of the island. The phrase appears to have used in the same sense as the designation of Lands End at the tip of Cornwall. He was unable to elicit a Polynesian name for the island itself, according to Barthel, oral tradition has it that the island was first named Te pito o te kainga a Hau Maka The little piece of land of Hau Maka. However, there are two words pronounced pito in Rapa Nui, one meaning end and one navel, and the phrase can also mean the Navel of the World. This was apparently its actual meaning, French ethnologist Alphonse Pinart gave it the actual translation the Navel of the World, another name, Mata ki te rangi, means Eyes looking to the sky. Islanders are referred to in Spanish as pascuense, however it is common to refer to members of the community as Rapa Nui. Estimated dates of initial settlement of Easter Island have ranged from 300 to 1200, rectifications in radiocarbon dating have changed almost all of the previously posited early settlement dates in Polynesia. Rapa Nui is now considered to have settled in the narrower range of 700 to 1100 CE. Significant ecological impacts and major cultural investments in monumental architecture and statuary thus began soon after initial settlement, according to oral tradition, the first settlement was at Anakena. The island was most likely populated by Polynesians who navigated in canoes or catamarans from the Gambier Islands or the Marquesas Islands,3,200 km away
13.
Moai
–
Moai /ˈmoʊ. aɪ/, or mo‘ai, are monolithic human figures carved by the Rapa Nui people on Easter Island in eastern Polynesia between 1250 and 1500 A. D. Nearly half are still at Rano Raraku, the main moai quarry, almost all moai have overly large heads three-eighths the size of the whole statue. The moai are chiefly the living faces of deified ancestors, the statues still gazed inland across their clan lands when Europeans first visited the island in 1722, but all of them had fallen by the latter part of the 19th century. The production and transportation of the more than 900 statues are considered remarkable creative, the moai toppled after European contact when islander traditions radically changed. The moai are monolithic statues, their minimalist style related to forms found throughout Polynesia, Moai are carved in relatively flat planes, the faces bearing proud but enigmatic expressions. The human figures would be outlined in the wall first. The over-large heads have heavy brows and elongated noses with a distinctive fish-hook-shaped curl of the nostrils, the lips protrude in a thin pout. Like the nose, the ears are elongated and oblong in form, the jaw lines stand out against the truncated neck. The torsos are heavy, and, sometimes, the clavicles are subtly outlined in stone, generally, the anatomical features of the backs are not detailed, but sometimes bear a ring and girdle motif on the buttocks and lower back. Except for one kneeling moai, the statues do not have clearly visible legs, though moai are whole-body statues, they are erroneously referred to as Easter Island heads in some popular literature. Some of the heads at Rano Raraku have been excavated and their bodies seen, the average height of the moai is about 4 m, with the average width at the base around 1.6 m. These massive creations usually weigh in at around 12.5 tonnes each, all but 53 of the more than 900 moai known to date were carved from tuff from Rano Raraku, where 394 moai and incomplete moai are still visible today. There are also 13 moai carved from basalt,22 from trachyte and 17 from fragile red scoria, at the end of carving, the builders would rub the statue with pumice. Easter Island statues are known for their large, broad noses and strong chins, along with rectangle-shaped ears and their bodies are normally squatting, with their arms resting in different positions and are without legs. The major of the ahu are found along the coast and face inland towards the community, there are some inland ahu such as Ahu Akivi. These moai face the community but given the size of the island. The discovery was made by collecting and reassembling broken fragments of coral that were found at the various sites. Subsequently, previously uncategorized finds in the Easter Island museum were re-examined and recategorized as eye fragments, many archaeologists suggest that statues were thus symbols of authority and power, both religious and political
14.
Volcanic gas
–
Volcanic gases include a variety of substances given off by active volcanoes. The sources of gases on Earth include, primordial and recycled constituents from the Earths mantle, assimilated constituents from the Earths crust, groundwater. Substances that may become gaseous or give off gases when heated are termed volatile substances. The principal components of volcanic gases are water vapor, carbon dioxide, sulfur either as sulfur dioxide or hydrogen sulfide, nitrogen, argon, helium, neon, methane, carbon monoxide and hydrogen. Other compounds detected in volcanic gases are oxygen, hydrogen chloride, hydrogen fluoride, hydrogen bromide, nitrogen oxide, sulfur hexafluoride, carbonyl sulfide, exotic trace compounds include mercury, halocarbons, and halogen oxide radicals. The abundance of gases varies considerably from volcano to volcano, water vapor is consistently the most common volcanic gas, normally comprising more than 60% of total emissions. Carbon dioxide typically accounts for 10 to 40% of emissions, volcanoes located at convergent plate boundaries emit more water vapor and chlorine than volcanoes at hot spots or divergent plate boundaries. This is caused by the addition of seawater into magmas formed at subduction zones, convergent plate boundary volcanoes also have higher H2O/H2, H2O/CO2, CO2/He and N2/He ratios than hot spot or divergent plate boundary volcanoes. Magma contains dissolved volatile components, as described above, the solubilities of the different volatile constituents are dependent on pressure, temperature and the composition of the magma. As magma ascends towards the surface, the ambient pressure decreases, once the solubility decreases below the volatile concentration, the volatiles will tend to come out of solution within the magma and form a separate gas phase. The gas will initially be distributed throughout the magma as small bubbles, as the magma ascends the bubbles grow through a combination of expansion through decompression and growth as the solubility of volatiles in the magma decreases further causing more gas to exsolve. In the former case, the bubbles may rise through the magma and accumulate at a vertical surface, in volcanoes with an open path to the surface, e. g. Stromboli in Italy, the bubbles may reach the surface and as they pop small explosions occur. In the latter case, the gas can flow rapidly through the continuous permeable network towards the surface and this mechanism has been used to explain activity at Santiaguito, Santa Maria volcano, Guatemala and Soufrière Hills Volcano, Montserrat. If the gas cannot escape fast enough from the magma, it will fragment the magma into small particles of ash, the fluidised ash has a much lower resistance to motion than the viscous magma, so accelerates, causing further expansion of the gases and acceleration of the mixture. This sequence of events drives explosive volcanism, whether gas can escape gently or not is determined by the total volatile contents of the initial magma and the viscosity of the magma, which is controlled by its composition. The term closed system degassing refers to the case where gas and its parent magma ascend together, the composition of the emitted gas is in equilibrium with the composition of the magma at the pressure, temperature where the gas leaves the system. In open system degassing, the gas leaves its parent magma, the gas released at the surface has a composition that is a mass-flow average of the magma exsolved at various depths and is not representative of the magma conditions at any one depth. Molten rock near the atmosphere releases high-temperature volcanic gas, in explosive volcanic eruptions, sudden release of gases from magma may cause rapid movements of the molten rock
15.
Steam
–
Steam is water in the gas phase, which is formed when water boils. Steam is invisible, however, steam often refers to wet steam, at lower pressures, such as in the upper atmosphere or at the top of high mountains, water boils at a lower temperature than the nominal 100 °C at standard pressure. If heated further it becomes superheated steam, piston type steam engines played a central role to the Industrial Revolution and modern steam turbines are used to generate more than 80% of the worlds electricity. If liquid water comes in contact with a hot surface or depressurizes quickly below its vapor pressure. Steam explosions have been responsible for many accidents, and may also have been responsible for much of the damage to the plant in the Chernobyl disaster. Steam is traditionally created by heating a boiler via burning coal and other fuels, water vapor that includes water droplets is described as wet steam. As wet steam is heated further, the droplets evaporate, and at a high temperature all of the water evaporates. Superheated steam is steam at a higher than its boiling point for the pressure. Steam tables contain thermodynamic data for water/steam and are used by engineers and scientists in design. Additionally, thermodynamic phase diagrams for water/steam, such as a diagram or a Mollier diagram shown in this article. Steam charts are used for analysing thermodynamic cycles. In agriculture, steam is used for sterilization to avoid the use of harmful chemical agents. Steams capacity to transfer heat is used in the home, for cooking vegetables, steam cleaning of fabric, carpets and flooring. In each case, water is heated in a boiler, steam is also used in ironing clothes to add enough humidity with the heat to take wrinkles out and put intentional creases into the clothing. About 90% of all electricity is generated using steam as the working fluid, in electric generation, steam is typically condensed at the end of its expansion cycle, and returned to the boiler for re-use. However, in cogeneration, steam is piped into buildings through a heating system to provide heat energy after its use in the electric generation cycle. The worlds biggest steam generation system is the New York City steam system, in other industrial applications steam is used for energy storage, which is introduced and extracted by heat transfer, usually through pipes. Steam is a reservoir for thermal energy because of waters high heat of vaporization
16.
Lava
–
Lava is the molten rock expelled by a volcano during an eruption. The resulting rock after solidification and cooling is called lava. The molten rock is formed in the interior of planets, including Earth. The source of the heat melts the rock within the earth is geothermal energy. When first erupted from a vent, lava is a liquid usually at temperatures from 700 to 1,200 °C. A lava flow is an outpouring of lava, which is created during a non-explosive effusive eruption. When it has stopped moving, lava solidifies to form igneous rock, the term lava flow is commonly shortened to lava. Although lava can be up to 100,000 times more viscous than water, lava can flow great distances before cooling and solidifying because of its thixotropic, explosive eruptions produce a mixture of volcanic ash and other fragments called tephra, rather than lava flows. The word lava comes from Italian, and is derived from the Latin word labes which means a fall or slide. The first use in connection with extruded magma was apparently in an account written by Francesco Serao on the eruption of Vesuvius between May 14 and June 4,1737. Serao described a flow of lava as an analogy to the flow of water. The composition of almost all lava of the Earths crust is dominated by silicate minerals, mostly feldspars, olivine, pyroxenes, amphiboles, micas, igneous rocks, which form lava flows when erupted, can be classified into three chemical types, felsic, intermediate, and mafic. These classes are primarily chemical, however, the chemistry of lava also tends to correlate with the temperature, its viscosity. Felsic or silicic lavas such as rhyolite and dacite typically form lava spines, most silicic lava flows are extremely viscous, and typically fragment as they extrude, producing blocky autobreccias. Felsic magmas can erupt at temperatures as low as 650 to 750 °C, unusually hot rhyolite lavas, however, may flow for distances of many tens of kilometres, such as in the Snake River Plain of the northwestern United States. Intermediate or andesitic lavas are lower in aluminium and silica, and usually somewhat richer in magnesium, intermediate lavas form andesite domes and block lavas, and may occur on steep composite volcanoes, such as in the Andes. Poorer in aluminium and silica than felsic lavas, and also commonly hotter, greater temperatures tend to destroy polymerized bonds within the magma, promoting more fluid behaviour and also a greater tendency to form phenocrysts. Higher iron and magnesium tends to manifest as a darker groundmass, mafic or basaltic lavas are typified by their high ferromagnesian content, and generally erupt at temperatures in excess of 950 °C
17.
Magma
–
Besides molten rock, magma may also contain suspended crystals, dissolved gas and sometimes gas bubbles. Magma often collects in magma chambers that may feed a volcano or solidify underground to form an intrusion, magma is capable of intruding into adjacent rocks, extrusion onto the surface as lava, and explosive ejection as tephra to form pyroclastic rock. Magma is a complex high-temperature fluid substance, temperatures of most magmas are in the range 700 °C to 1300 °C, but very rare carbonatite magmas may be as cool as 600 °C, and komatiite magmas may have been as hot as 1600 °C. Environments of magma formation and compositions are commonly correlated, environments include subduction zones, continental rift zones, mid-ocean ridges and hotspots. Despite being found in such locales, the bulk of the Earths crust. Except for the outer core, most of the Earth takes the form of a rheid. Magma, as liquid, preferentially forms in high temperature, low pressure environments within several kilometers of the Earths surface, magma compositions may evolve after formation by fractional crystallization, contamination, and magma mixing. By definition rock formed of solidified magma is called igneous rock, melting of solid rocks to form magma is controlled by three physical parameters, temperature, pressure, and composition. Mechanisms are discussed in the entry for igneous rock, as a rock melts, its volume changes. When enough rock is melted, the small globules of melt link up, under pressure within the earth, as little as a fraction of a percent partial melting may be sufficient to cause melt to be squeezed from its source. The degree of melting is critical for determining what type of magma is produced. The degree of partial melting required to form a melt can be estimated by considering the relative enrichment of incompatible elements versus compatible elements, incompatible elements commonly include potassium, barium, cesium, and rubidium. Rock types produced by small degrees of melting in the Earths mantle are typically alkaline. Typically, primitive melts of this composition form lamprophyre, lamproite, kimberlite and sometimes nepheline-bearing mafic rocks such as alkali basalts, pegmatite may be produced by low degrees of partial melting of the crust. Some granite-composition magmas are eutectic melts, and they may be produced by low to high degrees of melting of the crust. At high degrees of melting of the crust, granitoids such as tonalite, granodiorite and monzonite can be produced. Being only the time in recorded history that magma had been reached, IDDP decided to invest in the hole. A cemented steel case was constructed in the hole with a perforation at the close to the magma
18.
Tephra
–
Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts, once clasts have fallen to the ground they remain as tephra unless hot enough to fuse together into pyroclastic rock or tuff. Tephra mixed in with precipitation can also be acidic and cause acid rain, the use of tephra layers, which bear their own unique chemistry and character, as temporal marker horizons in archaeological and geological sites is known as tephrochronology. The word tephra and pyroclast both derive from Greek, τέφρα tephra means ash, while the word pyroclast is derived from the Greek πῦρ, meaning fire, media related to Tephra at Wikimedia Commons How Volcanoes Work Volcanic Materials Identification
19.
Extrusion
–
Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed through a die of the desired cross-section and it also forms parts with an excellent surface finish. Drawing is a process, which uses the tensile strength of the material to pull it through the die. This limits the amount of change which can be performed in one step, so it is limited to simpler shapes, Drawing is the main way to produce wire. Metal bars and tubes are often drawn. Extrusion may be continuous or semi-continuous, the extrusion process can be done with the material hot or cold. Commonly extruded materials include metals, polymers, ceramics, concrete, play dough, the products of extrusion are generally called extrudates. Hollow cavities within extruded material cannot be produced using a simple flat extrusion die, instead, the die assumes the shape of a block with depth, beginning first with a shape profile that supports the center section. The die shape then internally changes along its length into the final shape, the material flows around the supports and fuses together to create the desired closed shape. The extrusion process in metals may increase the strength of the material. In 1797, Joseph Bramah patented the first extrusion process for making out of soft metals. It involved preheating the metal and then forcing it through a die via a hand-driven plunger, in 1820 Thomas Burr implemented that process for lead pipe, with a hydraulic press. At that time the process was called squirting, in 1894, Alexander Dick expanded the extrusion process to copper and brass alloys. The process begins by heating the stock material and it is then loaded into the container in the press. A dummy block is placed behind it where the ram then presses on the material to push it out of the die, afterward the extrusion is stretched in order to straighten it. If better properties are required then it may be treated or cold worked. The extrusion ratio is defined as the starting cross-sectional area divided by the area of the final extrusion. One of the advantages of the extrusion process is that this ratio can be very large while still producing quality parts
20.
Sand
–
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. It is defined by size, being finer than gravel and coarser than silt, Sand can also refer to a textural class of soil or soil type, i. e. a soil containing more than 85% sand-sized particles by mass. The second most common type of sand is calcium carbonate, for example aragonite, for example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean. Sand is a non renewable resource over human timescales, and sand suitable for making concrete is in high demand, in terms of particle size as used by geologists, sand particles range in diameter from 0.0625 mm to 2 mm. An individual particle in this size is termed a sand grain. Sand grains are between gravel and silt, a 1953 engineering standard published by the American Association of State Highway and Transportation Officials set the minimum sand size at 0.074 mm. A1938 specification of the United States Department of Agriculture was 0.05 mm. Sand feels gritty when rubbed between the fingers. ISO14688 grades sands as fine, medium and coarse with ranges 0.063 mm to 0.2 mm to 0.63 mm to 2.0 mm. In the United States, sand is commonly divided into five sub-categories based on size, very fine sand, fine sand, medium sand, coarse sand, and very coarse sand. These sizes are based on the Krumbein phi scale, where size in Φ = -log2D, on this scale, for sand the value of Φ varies from −1 to +4, with the divisions between sub-categories at whole numbers. The composition of sand is highly variable, depending on the local rock sources. The gypsum sand dunes of the White Sands National Monument in New Mexico are famous for their bright, arkose is a sand or sandstone with considerable feldspar content, derived from weathering and erosion of a granitic rock outcrop. Some sands contain magnetite, chlorite, glauconite or gypsum, Sands rich in magnetite are dark to black in color, as are sands derived from volcanic basalts and obsidian. Chlorite-glauconite bearing sands are typically green in color, as are sands derived from basaltic with a high olivine content, many sands, especially those found extensively in Southern Europe, have iron impurities within the quartz crystals of the sand, giving a deep yellow color. Sand deposits in some areas contain garnets and other resistant minerals, the study of individual grains can reveal much historical information as to the origin and kind of transport of the grain. Quartz sand that is weathered from granite or gneiss quartz crystals will be angular. It is called grus in geology or sharp sand in the trade where it is preferred for concrete. Sand that is transported long distances by water or wind will be rounded, people who collect sand as a hobby are known as arenophiles
21.
Slag
–
Slag is the glass-like by-product left over after a desired metal has been separated from its raw ore. Slag is usually a mixture of oxides and silicon dioxide. However, slags can contain metal sulfides and elemental metals, in nature, iron, copper, lead, nickel and other metals are found in impure states called ores, often oxidized and mixed in with silicates of other metals. During smelting, when the ore is exposed to high temperatures, Slag is the collection of compounds that are removed. In many smelting processes, oxides are introduced to control the slag chemistry, assisting in the removal of impurities, in this case, the slag is termed synthetic. Ferrous and non-ferrous smelting processes produce different slags, the smelting of copper and lead in non-ferrous smelting, for instance, is designed to remove the iron and silica that often occurs with those ores, and separates them as iron-silicate-based slags. Slag from steel mills in ferrous smelting, on the hand, is designed to minimize iron loss and so mainly contains oxides of calcium, silicon, magnesium. Any sandy component or quartz component of the original ore automatically carries through the process as silicon dioxide. As the slag is channeled out of the furnace, water is poured over it and this rapid cooling, often from a temperature of around 2,600 °F, is the start of the granulating process. This process causes several chemical reactions to take place within the slag, the water carries the slag in its slurry format to a large agitation tank, from where it is pumped along a piping system into a number of gravel based filter beds. The filter beds then retain the slag granules, while the drains away and is returned to the system. During the Bronze Age of the Mediterranean there were a vast number of metallurgical processes in use. A slag by-product of such workings was a colorful, glassy and it was primarily blue or green and was formerly chipped away and melted down to make glassware products and jewelry. It was also ground into powder to add to glazes for use in ceramics, some of the earliest such uses for the by-products of slag have been found in ancient Egypt. Historically, the re-smelting of iron ore slag was common practice, during the early 20th century, iron ore slag was also ground to a powder and used to make agate glass, also known as slag glass. Ground granulated slag is used in concrete in combination with Portland cement as part of a blended cement. Ground granulated slag reacts with water to produce cementitious properties, concrete containing ground granulated slag develops strength over a longer period, leading to reduced permeability and better durability. Since the unit volume of Portland cement is reduced, this concrete is less vulnerable to alkali-silica, the slag can also be used to create fibers used as an insulation material called slag wool
22.
Mojave National Preserve
–
Mojave National Preserve is a United States National Preserve located in the Mojave Desert of San Bernardino County, California, USA, between Interstate 15 and Interstate 40. The preserve was established October 31,1994 with the passage of the California Desert Protection Act by the US Congress, previously, it was the East Mojave National Scenic Area, under the jurisdiction of the Bureau of Land Management. At 1,600,000 acres, it is the third largest unit of the National Park System in the contiguous United States. Natural features include the Kelso Dunes, the Marl Mountains and the Cima Dome, as well as volcanic formations such as Hole-in-the-Wall, the preserve encloses Providence Mountains State Recreation Area and Mitchell Caverns Natural Preserve, which are both managed by the California Department of Parks and Recreation. Impressive Joshua Tree forests cover parts of the preserve, the Cima Dome and Shadow Valley forests are the largest in the world. The defunct railroad depot and ghost town of Kelso are also found there, the depot is now the visitor center. The preserve is commonly traversed by 4 wheel drive vehicles traveling on the historic Mojave Road, summer temperatures average 90 °F, with highs exceeding 105 °F. Elevations in the Preserve range from 7,929 feet at Clark Mountain to 880 feet near Baker. Annual precipitation varies from 3.37 inches near Baker, to almost 9 inches in the mountains, at least 25% of precipitation comes from summer thunderstorms. Snow is often found in the mountains during the winter, the California Desert Protection Act of 1994 designated a wilderness area within Mojave National Preserve of approximately 695,200 acres. The National Park Service manages the wilderness in accordance with the Wilderness Act, the CDPA, the following climate data is for a higher elevation area in the preserve. See also Climate of the Mojave Desert, Mojave Memorial Cross Official website Photo tour of Mojave National Preserve - from USGS
23.
Germany
–
Germany, officially the Federal Republic of Germany, is a federal parliamentary republic in central-western Europe. It includes 16 constituent states, covers an area of 357,021 square kilometres, with about 82 million inhabitants, Germany is the most populous member state of the European Union. After the United States, it is the second most popular destination in the world. Germanys capital and largest metropolis is Berlin, while its largest conurbation is the Ruhr, other major cities include Hamburg, Munich, Cologne, Frankfurt, Stuttgart, Düsseldorf and Leipzig. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity, a region named Germania was documented before 100 AD. During the Migration Period the Germanic tribes expanded southward, beginning in the 10th century, German territories formed a central part of the Holy Roman Empire. During the 16th century, northern German regions became the centre of the Protestant Reformation, in 1871, Germany became a nation state when most of the German states unified into the Prussian-dominated German Empire. After World War I and the German Revolution of 1918–1919, the Empire was replaced by the parliamentary Weimar Republic, the establishment of the national socialist dictatorship in 1933 led to World War II and the Holocaust. After a period of Allied occupation, two German states were founded, the Federal Republic of Germany and the German Democratic Republic, in 1990, the country was reunified. In the 21st century, Germany is a power and has the worlds fourth-largest economy by nominal GDP. As a global leader in industrial and technological sectors, it is both the worlds third-largest exporter and importer of goods. Germany is a country with a very high standard of living sustained by a skilled. It upholds a social security and universal health system, environmental protection. Germany was a member of the European Economic Community in 1957. It is part of the Schengen Area, and became a co-founder of the Eurozone in 1999, Germany is a member of the United Nations, NATO, the G8, the G20, and the OECD. The national military expenditure is the 9th highest in the world, the English word Germany derives from the Latin Germania, which came into use after Julius Caesar adopted it for the peoples east of the Rhine. This in turn descends from Proto-Germanic *þiudiskaz popular, derived from *þeudō, descended from Proto-Indo-European *tewtéh₂- people, the discovery of the Mauer 1 mandible shows that ancient humans were present in Germany at least 600,000 years ago. The oldest complete hunting weapons found anywhere in the world were discovered in a mine in Schöningen where three 380, 000-year-old wooden javelins were unearthed
24.
Sedimentary rock
–
Sedimentary rocks are types of rock that are formed by the deposition and subsequent cementation of that material at the Earths surface and within bodies of water. Sedimentation is the name for processes that cause mineral and/or organic particles to settle in place. The particles that form a rock by accumulating are called sediment. Sedimentation may also occur as minerals precipitate from solution or shells of aquatic creatures settle out of suspension. The sedimentary rock cover of the continents of the Earths crust is extensive, sedimentary rocks are only a thin veneer over a crust consisting mainly of igneous and metamorphic rocks. Sedimentary rocks are deposited in layers as strata, forming a structure called bedding, sedimentary rocks are also important sources of natural resources like coal, fossil fuels, drinking water or ores. The study of the sequence of rock strata is the main source for an understanding of the Earths history, including palaeogeography, paleoclimatology. The scientific discipline that studies the properties and origin of rocks is called sedimentology. Sedimentology is part of both geology and physical geography and overlaps partly with other disciplines in the Earth sciences, such as pedology, geomorphology, geochemistry, sedimentary rocks have also been found on Mars. Clastic sedimentary rocks are composed of rock fragments that were cemented by silicate minerals. Clastic rocks are composed largely of quartz, feldspar, rock fragments, clay minerals, and mica, any type of mineral may be present, clastic sedimentary rocks, are subdivided according to the dominant particle size. Most geologists use the Udden-Wentworth grain size scale and divide unconsolidated sediment into three fractions, gravel, sand, and mud and this tripartite subdivision is mirrored by the broad categories of rudites, arenites, and lutites, respectively, in older literature. The subdivision of these three categories is based on differences in clast shape, conglomerates and breccias), composition. Conglomerates are dominantly composed of rounded gravel, while breccias are composed of dominantly angular gravel, composition of framework grains The relative abundance of sand-sized framework grains determines the first word in a sandstone name. Naming depends on the dominance of the three most abundant components quartz, feldspar, or the lithic fragments that originated from other rocks, all other minerals are considered accessories and not used in the naming of the rock, regardless of abundance. Clean sandstones with open space are called arenites. Muddy sandstones with abundant muddy matrix are called wackes, six sandstone names are possible using the descriptors for grain composition and the amount of matrix. Mudrocks are sedimentary rocks composed of at least 50% silt- and clay-sized particles and these relatively fine-grained particles are commonly transported by turbulent flow in water or air, and deposited as the flow calms and the particles settle out of suspension
25.
Recrystallization (geology)
–
The basic composition remains the same. This process can be illustrated by observing how snow recrystallizes to ice without melting, as opposed to metasomatism, which is a chemical change caused by metamorphism, recrystallization is a physical process. However, recrystallization can occur when a local migration of chemicals results in the change of the rock or mineral with no external addition of materials. Limestone is a rock that undergoes metamorphic recrystallization to form marble
26.
Mount Bandai
–
Mount Bandai is a stratovolcano located in Inawashiro-town, Bandai-town, and Kitashiobara village, in Yama-Gun, Fukushima prefecture. It is a stratovolcano located to the north of Lake Inawashiro. Mount Bandai, including the Bandai heights, belongs to the Bandai-Asahi National Park, the altitude of the triangulation station “Bandai”, installed in 1904, had been employed as the official altitude of Mount Bandai. However, after the station disappeared due to erosion, it was re-measured in October 2010, Mount Bandai was originally called “Iwahashi-yama” which means “a rock ladder to the sky. ”It is now sometimes called “Aizu Fuji” and “Aizu Bandai”. The south foot is called Omotebandai and the foot is called Urabandai. When seen from Omotebandai, the mountain looks very tidy, but when viewed from Urabandai the mountain shows a wild shape and it is one of the list of the 100 famous mountains in Japan. In 2007, the mountain was selected as one of the top 100 geographic landmarks in Japan, additionally, in 2011 the mountain was certified as a geopark of Japan. <<Volcanic Activity>> Typical features of mount Bandai’s activity are debris avalanches and we know this because evidence of this has been left in past activities. Mount Bandai has not experienced a lava flow after the eruption of about 10000 years ago, sediment surveys have shown us that the history of the volcano can be divided into 6 sections. It is thought that the activity period was from about 290,000 years ago when there were 2 scoria eruptions. 1.1 million years ago to 350,000 years ago, approximately 290,000 years ago, there were two scoria eruptions. From about 210000 years to 200000 years ago there were several scoria, approximately 165,000 to 145,000 years ago, there were eruptions of volcanic ash and pumice. From about 80,000 years ago to 65,000 years ago, there were sub-plinian and Vulcanian eruptions of pumice, approximately 40,000 to 50,000 years ago, there was continuous activity with pumice eruptions, and sector collapse. On July 15,1888 there was an explosion of vapour in a Kobandai eruption. It is believed that hot ground water continuously spurting out had weathered the mountain and this caused an avalanche of debris to bury 5 nearby villages on the north foot of the mountain and 477 people were killed. This eruption was the first major disaster to the modern Japanese government which began from the Meiji period, the government launched an enquiry to investigate the eruption and this was implemented by Kiyokage Sekiya and Yasu Kikuchi. The government provided relief and attempted to rebuild the affected villages, extensive research, including surveys was undertaken into the causes of the eruption and the extent of the damage – this was an unusual measure to take at the time. Detailed pictures were taken of the events, donations amounting to ¥38,000 were gathered and these supported the relief and restoration effort
27.
Japan
–
Japan is a sovereign island nation in Eastern Asia. Located in the Pacific Ocean, it lies off the eastern coast of the Asia Mainland and stretches from the Sea of Okhotsk in the north to the East China Sea, the kanji that make up Japans name mean sun origin. 日 can be read as ni and means sun while 本 can be read as hon, or pon, Japan is often referred to by the famous epithet Land of the Rising Sun in reference to its Japanese name. Japan is an archipelago consisting of about 6,852 islands. The four largest are Honshu, Hokkaido, Kyushu and Shikoku, the country is divided into 47 prefectures in eight regions. Hokkaido being the northernmost prefecture and Okinawa being the southernmost one, the population of 127 million is the worlds tenth largest. Japanese people make up 98. 5% of Japans total population, approximately 9.1 million people live in the city of Tokyo, the capital of Japan. Archaeological research indicates that Japan was inhabited as early as the Upper Paleolithic period, the first written mention of Japan is in Chinese history texts from the 1st century AD. Influence from other regions, mainly China, followed by periods of isolation, from the 12th century until 1868, Japan was ruled by successive feudal military shoguns who ruled in the name of the Emperor. Japan entered into a period of isolation in the early 17th century. The Second Sino-Japanese War of 1937 expanded into part of World War II in 1941, which came to an end in 1945 following the bombings of Hiroshima and Nagasaki. Japan is a member of the UN, the OECD, the G7, the G8, the country has the worlds third-largest economy by nominal GDP and the worlds fourth-largest economy by purchasing power parity. It is also the worlds fourth-largest exporter and fourth-largest importer, although Japan has officially renounced its right to declare war, it maintains a modern military with the worlds eighth-largest military budget, used for self-defense and peacekeeping roles. Japan is a country with a very high standard of living. Its population enjoys the highest life expectancy and the third lowest infant mortality rate in the world, in ancient China, Japan was called Wo 倭. It was mentioned in the third century Chinese historical text Records of the Three Kingdoms in the section for the Wei kingdom, Wa became disliked because it has the connotation of the character 矮, meaning dwarf. The 倭 kanji has been replaced with the homophone Wa, meaning harmony, the Japanese word for Japan is 日本, which is pronounced Nippon or Nihon and literally means the origin of the sun. The earliest record of the name Nihon appears in the Chinese historical records of the Tang dynasty, at the start of the seventh century, a delegation from Japan introduced their country as Nihon
28.
Eifel
–
The Eifel is a low mountain range in western Germany and eastern Belgium. It occupies parts of southwestern North Rhine-Westphalia, northwestern Rhineland-Palatinate and the south of the German-speaking Community of Belgium, the Eifel is part of the Rhenish Massif, within its northern portions lies the Eifel National Park. The Eifel lies between the cities of Aachen to the north, Trier to the south and Koblenz to the east and it descends in the northeast along a line from Aachen via Düren to Bonn into the Lower Rhine Bay. In the east and south it is bounded by the valleys of the Rhine, to the west it transitions in Belgium and Luxembourg into the geologically related Ardennes and the Luxembourg Ösling. In the north it is limited by the Jülich-Zülpicher Börde, within Germany it lies within the states of Rhineland-Palatinate and North Rhine-Westphalia, in BeNeLux the area of Eupen, St. Vith and Luxembourg. Its highest point is the cone of the Hohe Acht. Originally the Carolingian Eifelgau only covered the region roughly around the sources of the rivers Ahr, Kyll. Its name was recently transferred to the entire region. Individual mountain chains, up to 700 m, such as the Schneifel and High Fens, run through the western part of the plateau. The rivers draining into the Moselle, Rhine and Meuse, such as the Our, Kyll, Ahr, Brohl and Rur, have cut deep into the edge of the Eifel and formed larger valleys. The Eifel covers an area of 5,300 km² and is divided into the North and South Eifel. It is further divided into several natural regional landscapes, some with further subdivisions, there are several distinct chains within the Eifel. The northernmost parts are called North Eifel including Rur Eifel the origin of the river Rur, High Fens, the northeastern part is called Ahr Hills and rise north of the Ahr river in the district of Ahrweiler. South of the Ahr is the High Eifel, with the Hohe Acht being the highest mountain of the Eifel, in the west, on the Belgian border, the hills are known as Schneifel, rising up to 698 m. Also in the west, by the Belgian and Luxembourg border, the southern half of the Eifel is lower. It is cut by rivers running north-south towards the Moselle. The largest of these is the Kyll, and the hills on either side of river are called the Kyllwald. In the south the Eifel is concluded by the Voreifel above the Moselle, since 2004 about 110 km² of the Eifel within the German state of North Rhine-Westphalia have been protected as the Eifel National Park nature reserve
29.
Devonian
–
The Devonian is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian,419.2 million years ago, to the beginning of the Carboniferous,358.9 Mya. It is named after Devon, England, where rocks from this period were first studied, the first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents, by the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. Various terrestrial arthropods also became well-established, Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fish. The first ray-finned and lobe-finned bony fish appeared, while the placodermi began dominating almost every aquatic environment. The ancestors of all four-limbed vertebrates began adapting to walking on land, as their strong pectoral, in the oceans, primitive sharks became more numerous than in the Silurian and Late Ordovician. The first ammonites, species of molluscs, appeared, trilobites, the mollusk-like brachiopods and the great coral reefs, were still common. The Late Devonian extinction which started about 375 million years ago severely affected marine life, killing off all placodermi, and all trilobites, save for a few species of the order Proetida. The palaeogeography was dominated by the supercontinent of Gondwana to the south, the continent of Siberia to the north, while the rock beds that define the start and end of the Devonian period are well identified, the exact dates are uncertain. According to the International Commission on Stratigraphy, the Devonian extends from the end of the Silurian 419.2 Mya, another common term is Age of the Fishes, referring to the evolution of several major groups of fish that took place during the period. Older literature on the Anglo-Welsh basin divides it into the Downtonian, Dittonian, Breconian and Farlovian stages, in the Late Devonian, by contrast, arid conditions were less prevalent across the world and temperate climates were more common. The Devonian Period is formally broken into Early, Middle and Late subdivisions, the rocks corresponding to those epochs are referred to as belonging to the Lower, Middle and Upper parts of the Devonian System. Early Devonian The Early Devonian lasted from 419.2 ±2.8 to 393.3 ±2.5 and began with the Lochkovian stage, which lasted until the Pragian. It spanned from 410.8 ±2.8 to 407.6 ±2.5, and was followed by the Emsian, which lasted until the Middle Devonian began,393. 3±2.7 million years ago. Middle Devonian The Middle Devonian comprised two subdivisions, first the Eifelian, which gave way to the Givetian 387. 7±2.7 million years ago. Late Devonian Finally, the Late Devonian started with the Frasnian,382.7 ±2.8 to 372.2 ±2.5, during which the first forests took shape on land. The first tetrapods appeared in the record in the ensuing Famennian subdivision. This lasted until the end of the Devonian,358. 9±2.5 million years ago, the Devonian was a relatively warm period, and probably lacked any glaciers
30.
Scotland
–
Scotland is a country that is part of the United Kingdom and covers the northern third of the island of Great Britain. It shares a border with England to the south, and is surrounded by the Atlantic Ocean, with the North Sea to the east. In addition to the mainland, the country is made up of more than 790 islands, including the Northern Isles, the Kingdom of Scotland emerged as an independent sovereign state in the Early Middle Ages and continued to exist until 1707. By inheritance in 1603, James VI, King of Scots, became King of England and King of Ireland, Scotland subsequently entered into a political union with the Kingdom of England on 1 May 1707 to create the new Kingdom of Great Britain. The union also created a new Parliament of Great Britain, which succeeded both the Parliament of Scotland and the Parliament of England. Within Scotland, the monarchy of the United Kingdom has continued to use a variety of styles, titles, the legal system within Scotland has also remained separate from those of England and Wales and Northern Ireland, Scotland constitutes a distinct jurisdiction in both public and private law. Glasgow, Scotlands largest city, was one of the worlds leading industrial cities. Other major urban areas are Aberdeen and Dundee, Scottish waters consist of a large sector of the North Atlantic and the North Sea, containing the largest oil reserves in the European Union. This has given Aberdeen, the third-largest city in Scotland, the title of Europes oil capital, following a referendum in 1997, a Scottish Parliament was re-established, in the form of a devolved unicameral legislature comprising 129 members, having authority over many areas of domestic policy. Scotland is represented in the UK Parliament by 59 MPs and in the European Parliament by 6 MEPs, Scotland is also a member nation of the British–Irish Council, and the British–Irish Parliamentary Assembly. Scotland comes from Scoti, the Latin name for the Gaels, the Late Latin word Scotia was initially used to refer to Ireland. By the 11th century at the latest, Scotia was being used to refer to Scotland north of the River Forth, alongside Albania or Albany, the use of the words Scots and Scotland to encompass all of what is now Scotland became common in the Late Middle Ages. Repeated glaciations, which covered the land mass of modern Scotland. It is believed the first post-glacial groups of hunter-gatherers arrived in Scotland around 12,800 years ago, the groups of settlers began building the first known permanent houses on Scottish soil around 9,500 years ago, and the first villages around 6,000 years ago. The well-preserved village of Skara Brae on the mainland of Orkney dates from this period and it contains the remains of an early Bronze Age ruler laid out on white quartz pebbles and birch bark. It was also discovered for the first time that early Bronze Age people placed flowers in their graves, in the winter of 1850, a severe storm hit Scotland, causing widespread damage and over 200 deaths. In the Bay of Skaill, the storm stripped the earth from a large irregular knoll, when the storm cleared, local villagers found the outline of a village, consisting of a number of small houses without roofs. William Watt of Skaill, the laird, began an amateur excavation of the site, but after uncovering four houses
31.
Breccia
–
Breccia is a rock composed of broken fragments of minerals or rock cemented together by a fine-grained matrix that can be similar to or different from the composition of the fragments. The word has its origins in the Italian language, in which it means either loose gravel or stone made by cemented gravel. A breccia may have a variety of different origins, as indicated by the named types including sedimentary breccia, tectonic breccia, igneous breccia, impact breccia, and hydrothermal breccia. Sedimentary breccia is a type of sedimentary rock which is made of angular to subangular. A conglomerate, by contrast, is a rock composed of rounded fragments or clasts of pre-existing rocks. Both breccia and conglomerate are composed of fragments averaging greater than 2 millimetres in size, the angular shape of the fragments indicates that the material has not been transported far from its source. Sedimentary breccia consists of angular, poorly sorted, immature fragments of rocks in a finer grained groundmass which are produced by mass wasting and it is lithified colluvium or scree. Thick sequences of sedimentary breccia are generally formed next to fault scarps in grabens, Breccia may occur along a buried stream channel where it indicates accumulation along a juvenile or rapidly flowing stream. Sedimentary breccia may be formed by debris flows. Turbidites occur as fine-grained peripheral deposits to sedimentary breccia flows, in a karst terrain, a collapse breccia may form due to collapse of rock into a sinkhole or in cave development. Fault breccia results from the action of two fault blocks as they slide past each other. Subsequent cementation of these fragments may occur by means of the introduction of mineral matter in groundwater. Volcanic pyroclastic rocks are formed by explosive eruption of lava and any rocks which are entrained within the eruptive column and this may include rocks plucked off the wall of the magma conduit, or physically picked up by the ensuing pyroclastic surge. Lavas, especially rhyolite and dacite flows, tend to form volcanic rocks by a process known as autobrecciation. This occurs when the thick, nearly solid lava breaks up into blocks, the resulting breccia is uniform in rock type and chemical composition. Lavas may also pick up rock fragments, especially if flowing over unconsolidated rubble on the flanks of a volcano, within the volcanic conduits of explosive volcanoes the volcanic breccia environment merges into the intrusive breccia environment. There the upwelling lava tends to solidify during quiescent intervals only to be shattered by ensuing eruptions, clastic rocks are also commonly found in shallow subvolcanic intrusions such as porphyry stocks, granites and kimberlite pipes, where they are transitional with volcanic breccias. Intrusive rocks can become brecciated in appearance by multiple stages of intrusion and this may be seen in many granite intrusions where later aplite veins form a late-stage stockwork through earlier phases of the granite mass
32.
Volcanic bomb
–
A volcanic bomb is a mass of molten rock larger than 64 mm in diameter, formed when a volcano ejects viscous fragments of lava during an eruption. They cool into solid fragments before they reach the ground, because volcanic bombs cool after they leave the volcano, they are extrusive igneous rocks. Volcanic bombs can be many kilometres from an erupting vent. Bombs can be large, the 1935 eruption of Mount Asama in Japan expelled bombs measuring 5–6 m in diameter up to 600 m from the vent. Volcanic bombs are a significant volcanic hazard, and can cause severe injuries, one such incident occurred at Galeras volcano in Colombia in 1993, six people near the summit were killed and several seriously injured by lava bombs when the volcano erupted unexpectedly. Volcanic bombs are known to explode from internal gas pressure as they cool. Bomb explosions are most often observed in bread-crust type bombs, bombs are named according to their shape, which is determined by the fluidity of the magma from which they are formed. Ribbon or cylindrical bombs form from highly to moderately fluid magma, ejected as irregular strings, the strings break up into small segments which fall to the ground intact and look like ribbons. These bombs are circular or flattened in cross section, are fluted along their length, spherical bombs also form from high to moderately fluid magma. In the case of spherical bombs, surface tension plays a role in pulling the ejecta into spheres. Spindle, fusiform, or almond/rotational bombs are formed by the processes as spherical bombs. Spinning during flight leaves these bombs looking elongated or almond shaped, spindle bombs are characterised by longitudinal fluting, one side slightly smoother and broader than the other. This smooth side represents the underside of the bomb as it fell through the air, cow pie bombs are formed when highly fluid magma falls from moderate height, so the bombs do not solidify before impact. They consequently flatten or splash and form irregular roundish disks, which resemble cow dung, bread-crust bombs are formed if the outside of the lava bombs solidifies during their flights. They may develop cracked outer surfaces as the interiors continue to expand, cored bombs are bombs that have rinds of lava enclosing a core of previously consolidated lava. The core consists of fragments of an earlier eruption, accidental fragments of country rock or, in rare cases. Media related to Volcanic bombs at Wikimedia Commons USGS Volcano Hazards Program
33.
Agglomerate
–
Agglomerates are coarse accumulations of large blocks of volcanic material that contain at least 75% bombs. Globular masses of lava may have shot from the crater at a time when partly molten lava was exposed. These bombs were viscous at the moment of ejection and by rotation in the air acquired their shape and they are commonly 1 to 2 feet in diameter, but specimens as large as 12 feet have been observed. There is less variety in their composition at any one volcanic centre than in the case of the lithic blocks, agglomerates are typically found near volcanic vents and within volcanic conduits, where they may be associated with pyroclastic or intrusive volcanic breccias. Agglomerates are typically sorted, may contain a fine ash or tuff matrix. They may be monolithologic or heterolithic, and may contain some blocks of igneous rocks. There are various differences between agglomerates and ordinary ash beds or tuffs, agglomerates are coarser and less frequently well-bedded. Agglomerates can be non-welded or welded, such as coarse basaltic spatter and they typically form proximally during Strombolian eruptions, and are common at strongly peralkaline volcanoes. Some large agglomerate deposits are deposited from pyroclastic density currents during explosive caldera-forming eruptions, such as at Santorini, Taal and they may be massive to crudely bedded, and can attain great thicknesses. Crystalline masses of a different kind occur in numbers in certain agglomerates. The sanidinites of the Eifel belong to this group, at Vesuvius, Ascension, St Vincent and many other volcanoes, they form a considerable part of the coarser ash-beds. Their commonest minerals are olivine, anorthite, hornblende, augite, biotite and leucite and this article incorporates text from a publication now in the public domain, Chisholm, Hugh, ed. Agglomerate
34.
Rome
–
Rome is a special comune and the capital of Italy. Rome also serves as the capital of the Lazio region, with 2,873,598 residents in 1,285 km2, it is also the countrys largest and most populated comune and fourth-most populous city in the European Union by population within city limits. It is the center of the Metropolitan City of Rome, which has a population of 4.3 million residents, the city is located in the central-western portion of the Italian Peninsula, within Lazio, along the shores of the Tiber. Romes history spans more than 2,500 years, while Roman mythology dates the founding of Rome at only around 753 BC, the site has been inhabited for much longer, making it one of the oldest continuously occupied sites in Europe. The citys early population originated from a mix of Latins, Etruscans and it was first called The Eternal City by the Roman poet Tibullus in the 1st century BC, and the expression was also taken up by Ovid, Virgil, and Livy. Rome is also called the Caput Mundi, due to that, Rome became first one of the major centres of the Italian Renaissance, and then the birthplace of both the Baroque style and Neoclassicism. Famous artists, painters, sculptors and architects made Rome the centre of their activity, in 1871 Rome became the capital of the Kingdom of Italy, and in 1946 that of the Italian Republic. Rome has the status of a global city, Rome ranked in 2014 as the 14th-most-visited city in the world, 3rd most visited in the European Union, and the most popular tourist attraction in Italy. Its historic centre is listed by UNESCO as a World Heritage Site, monuments and museums such as the Vatican Museums and the Colosseum are among the worlds most visited tourist destinations with both locations receiving millions of tourists a year. Rome hosted the 1960 Summer Olympics and is the seat of United Nations Food, however, it is a possibility that the name Romulus was actually derived from Rome itself. As early as the 4th century, there have been alternate theories proposed on the origin of the name Roma. There is archaeological evidence of occupation of the Rome area from approximately 14,000 years ago. Evidence of stone tools, pottery and stone weapons attest to about 10,000 years of human presence, several excavations support the view that Rome grew from pastoral settlements on the Palatine Hill built above the area of the future Roman Forum. Between the end of the age and the beginning of the Iron age. However, none of them had yet an urban quality, nowadays, there is a wide consensus that the city was gradually born through the aggregation of several villages around the largest one, placed above the Palatine. All these happenings, which according to the excavations took place more or less around the mid of the 8th century BC. Despite recent excavations at the Palatine hill, the view that Rome has been indeed founded with an act of will as the legend suggests in the middle of the 8th century BC remains a fringe hypothesis. Traditional stories handed down by the ancient Romans themselves explain the earliest history of their city in terms of legend and myth
35.
Mount Etna
–
Mount Etna is an active stratovolcano on the east coast of Sicily, Italy, in the Metropolitan City of Catania, between the cities of Messina and Catania. It lies above the convergent plate margin between the African Plate and the Eurasian Plate and it is the tallest active volcano in Europe, currently 3,329 m high, though this varies with summit eruptions. It is the highest peak in Italy south of the Alps, Etna covers an area of 1,190 km2 with a basal circumference of 140 km. This makes it by far the largest of the three volcanoes in Italy, being about two and a half times the height of the next largest, Mount Vesuvius. Only Mount Teide in Tenerife surpasses it in the whole of the European–North-African region, Mount Etna is one of the most active volcanoes in the world and is in an almost constant state of activity. The fertile volcanic soils support extensive agriculture, with vineyards and orchards spread across the slopes of the mountain. Due to its history of recent activity and nearby population, Mount Etna has been designated a Decade Volcano by the United Nations, in June 2013, it was added to the list of UNESCO World Heritage Sites. According to Adrian Room’s book Place-names of the World, the name Etna originated from the Phoenician word attuna meaning furnace or chimney and he dismisses the hypothesis that Etna is from the Greek αἴθω, meaning I burn, through an iotacist pronunciation. In Classical Greek, it is called Αἴτνη, a name also to Catania and the city originally known as Inessa. In Arabic, it was called جبل النار Jabal al-Nār and it is also known as Mungibeddu in Sicilian and Mongibello or Montebello in Italian. The term is not in use today, although some older people still call it this. According to another hypothesis the term Mongibello comes from the Latin Mulciber, the people of the Etna sometimes use the jargon term a muntagna, simply the mountain par excellence. Nowadays, the term Mongibello indicates the top area of the two central craters encompassing also the craters in the southeast and the northeast of the volcanic cone. Volcanic activity first took place at Etna about 500,000 years ago, about 300,000 years ago, volcanism began occurring to the southwest of the summit then, before activity moved towards the present centre 170,000 years ago. Eruptions at this time built up the first major volcanic edifice, the growth of the mountain was occasionally interrupted by major eruptions, leading to the collapse of the summit to form calderas. From about 35,000 to 15,000 years ago, Etna experienced some highly explosive eruptions, generating pyroclastic flows. Ash from these eruptions has been found as far away as south of Romes border,800 km to the north, the landslide left a large depression in the side of the volcano, known as Valle del Bove. Research published in 2006 suggested this occurred around 8000 years ago, and caused a huge tsunami and it may have been the reason the settlement of Atlit Yam, now below sea level, was suddenly abandoned around that time
36.
Mount Vesuvius
–
Mount Vesuvius is a somma-stratovolcano located on the Gulf of Naples in Campania, Italy, about 9 km east of Naples and a short distance from the shore. It is one of several volcanoes which form the Campanian volcanic arc, Vesuvius consists of a large cone partially encircled by the steep rim of a summit caldera caused by the collapse of an earlier and originally much higher structure. Mount Vesuvius is best known for its eruption in AD79 that led to the burying and destruction of the Roman cities of Pompeii and Herculaneum, more than 1,000 people died in the eruption, but exact numbers are unknown. The only surviving account of the event consists of two letters by Pliny the Younger to the historian Tacitus. Vesuvius has erupted many times since and is the volcano on the European mainland to have erupted within the last hundred years. Vesuvius has a historic and literary tradition. An inscription from Capua to IOVI VESVVIO indicates that he was worshipped as a power of Jupiter and it was inhabited by bandits, the sons of the Earth, who were giants. With the assistance of the gods he pacified the region and went on, the facts behind the tradition, if any, remain unknown, as does whether Herculaneum was named after it. An epigram by the poet Martial in 88 AD suggests that both Venus, patroness of Pompeii, and Hercules were worshipped in the devastated by the eruption of 79. Mount Vesuvius was regarded by the Romans as being devoted to the hero, Vesuvius was a name of the volcano in frequent use by the authors of the late Roman Republic and the early Roman Empire. Its collateral forms were Vesaevus, Vesevus, Vesbius and Vesvius, writers in ancient Greek used Οὐεσούιον or Οὐεσούιος. Many scholars since then have offered an etymology, as peoples of varying ethnicity and language occupied Campania in the Roman Iron Age, the etymology depends to a large degree on the presumption of what language was spoken there at the time. Naples was settled by Greeks, as the name Nea-polis, New City, the Oscans, a native Italic people, lived in the countryside. The Latins also competed for the occupation of Campania, etruscan settlements were in the vicinity. Other peoples of unknown provenance are said to have been there at some time by various ancient authors. Some theories about its origin are, From Greek οὔ = not prefixed to a root from or related to the Greek word σβέννυμι = I quench, from Greek ἕω = I hurl and βίη violence, hurling violence, *vesbia, taking advantage of the collateral form. From an Indo-European root, *eus- < *ewes- < *wes-, shine sense the one who lightens, the Gran Cono was produced during the A. D.79 eruption. For this reason, the volcano is also called Somma-Vesuvius or Somma-Vesuvio, the caldera started forming during an eruption around 17,000 years ago and was enlarged by later paroxysmal eruptions, ending in the one of AD79
37.
Limestone
–
Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate, about 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to karst landscapes, most cave systems are through limestone bedrock. The first geologist to distinguish limestone from dolomite was Belsazar Hacquet in 1778, like most other sedimentary rocks, most limestone is composed of grains. Most grains in limestone are skeletal fragments of organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids, intraclasts and these organisms secrete shells made of aragonite or calcite, and leave these shells behind when they die. Limestone often contains variable amounts of silica in the form of chert or siliceous skeletal fragment, some limestones do not consist of grains at all, and are formed completely by the chemical precipitation of calcite or aragonite, i. e. travertine. Secondary calcite may be deposited by supersaturated meteoric waters and this produces speleothems, such as stalagmites and stalactites. Another form taken by calcite is oolitic limestone, which can be recognized by its granular appearance, the primary source of the calcite in limestone is most commonly marine organisms. Some of these organisms can construct mounds of rock known as reefs, below about 3,000 meters, water pressure and temperature conditions cause the dissolution of calcite to increase nonlinearly, so limestone typically does not form in deeper waters. Limestones may also form in lacustrine and evaporite depositional environments, calcite can be dissolved or precipitated by groundwater, depending on several factors, including the water temperature, pH, and dissolved ion concentrations. Calcite exhibits a characteristic called retrograde solubility, in which it becomes less soluble in water as the temperature increases. Impurities will cause limestones to exhibit different colors, especially with weathered surfaces, Limestone may be crystalline, clastic, granular, or massive, depending on the method of formation. Crystals of calcite, quartz, dolomite or barite may line small cavities in the rock, when conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together, or it can fill fractures. Travertine is a banded, compact variety of limestone formed along streams, particularly there are waterfalls. Calcium carbonate is deposited where evaporation of the leaves a solution supersaturated with the chemical constituents of calcite. Tufa, a porous or cellular variety of travertine, is found near waterfalls, coquina is a poorly consolidated limestone composed of pieces of coral or shells. During regional metamorphism that occurs during the building process, limestone recrystallizes into marble
38.
Clay
–
Clay is a fine-grained natural rock or soil material that combines one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure. Clays are plastic due to water content and become hard, brittle. Depending on the content in which it is found, clay can appear in various colours from white to dull grey or brown to deep orange-red. Although many naturally occurring deposits include both silts and clay, clays are distinguished from other fine-grained soils by differences in size, silts, which are fine-grained soils that do not include clay minerals, tend to have larger particle sizes than clays. There is, however, some overlap in size and other physical properties. The distinction between silt and clay varies by discipline, geologists and soil scientists usually consider the separation to occur at a particle size of 2 µm, sedimentologists often use 4–5 μm, and colloid chemists use 1 μm. Geotechnical engineers distinguish between silts and clays based on the plasticity properties of the soil, as measured by the soils Atterberg limits, ISO14688 grades clay particles as being smaller than 2 μm and silt particles as being larger. These solvents, usually acidic, migrate through the rock after leaching through upper weathered layers. In addition to the process, some clay minerals are formed through hydrothermal activity. There are two types of deposits, primary and secondary. Primary clays form as residual deposits in soil and remain at the site of formation, secondary clays are clays that have been transported from their original location by water erosion and deposited in a new sedimentary deposit. Clay deposits are associated with very low energy depositional environments such as large lakes. Depending on the source, there are three or four main groups of clays, kaolinite, montmorillonite-smectite, illite, and chlorite. Chlorites are not always considered to be a clay, sometimes being classified as a group within the phyllosilicates. There are approximately 30 different types of clays in these categories. Varve is clay with visible annual layers, which are formed by deposition of those layers and are marked by differences in erosion. This type of deposit is common in glacial lakes
39.
Fossil
–
Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record. The study of fossils across geological time, how they were formed, such a preserved specimen is called a fossil if it is older than some minimum age, most often the arbitrary date of 10,000 years. The observation that fossils were associated with certain rock strata led early geologists to recognize a geological timescale in the 19th century. The development of dating techniques in the early 20th century allowed geologists to determine the numerical or absolute age of the various strata. Like extant organisms, fossils vary in size from microscopic, even single bacterial cells one micrometer in diameter, to gigantic, such as dinosaurs, Fossils may also consist of the marks left behind by the organism while it was alive, such as animal tracks or feces. These types of fossil are called trace fossils, as opposed to body fossils, finally, past life leaves some markers that cannot be seen but can be detected in the form of biochemical signals, these are known as chemofossils or biosignatures. The process of fossilization varies according to type and external conditions. Permineralization is a process of fossilization that occurs when an organism is buried, the empty spaces within an organism become filled with mineral-rich groundwater. Minerals precipitate from the groundwater, occupying the empty spaces and this process can occur in very small spaces, such as within the cell wall of a plant cell. Small scale permineralization can produce very detailed fossils, for permineralization to occur, the organism must become covered by sediment soon after death or soon after the initial decay process. The degree to which the remains are decayed when covered determines the later details of the fossil, some fossils consist only of skeletal remains or teeth, other fossils contain traces of skin, feathers or even soft tissues. This is a form of diagenesis, in some cases the original remains of the organism completely dissolve or are otherwise destroyed. The remaining organism-shaped hole in the rock is called an external mold, if this hole is later filled with other minerals, it is a cast. An endocast or internal mold is formed when sediments or minerals fill the cavity of an organism. This is a form of cast and mold formation. If the chemistry is right, the organism can act as a nucleus for the precipitation of minerals such as siderite, if this happens rapidly before significant decay to the organic tissue, very fine three-dimensional morphological detail can be preserved. Nodules from the Carboniferous Mazon Creek fossil beds of Illinois, USA, are among the best documented examples of such mineralization, replacement occurs when the shell, bone or other tissue is replaced with another mineral
40.
Exoskeleton
–
An exoskeleton is the external skeleton that supports and protects an animals body, in contrast to the internal skeleton of, for example, a human. In usage, some of the kinds of exoskeletons are known as shells. Examples of animals with exoskeletons include insects such as grasshoppers and cockroaches, the shells of certain sponges and the various groups of shelled molluscs, including those of snails, clams, tusk shells, chitons and nautilus, are also exoskeletons. Some animals, such as the tortoise, have both an endoskeleton and an exoskeleton, exoskeletons have a role in defense from pests and predators, support, and in providing an attachment framework for musculature. Exoskeletons contain chitin, the addition of calcium carbonate makes them harder and stronger, ingrowths of the arthropod exoskeleton known as apodemes serve as attachment sites for muscles. These structures are composed of chitin, and are six times as strong. Similar to tendons, apodemes can stretch to store energy for jumping. Many different species produce exoskeletons, which are composed of a range of materials, bone, cartilage, or dentine is used in the Ostracoderm fish and turtles. Chitin forms the exoskeleton in arthropods including insects, arachnids such as spiders, crustaceans such as crabs and lobsters, calcium carbonates constitute the shells of molluscs, brachiopods, and some tube-building polychaete worms. Silica forms the exoskeleton in the microscopic diatoms and radiolaria, one species of mollusc, the scaly-foot gastropod, even makes use of the iron sulfides greigite and pyrite. Some organisms, such as some foraminifera, agglutinate exoskeletons by sticking grains of sand, contrary to a common misconception, echinoderms do not possess an exoskeleton, as their test is always contained within a layer of living tissue. Exoskeletons have evolved many times,18 lineages evolved calcified exoskeletons alone. Further, other lineages have produced tough outer coatings analogous to an exoskeleton and this coating is constructed from bone in the armadillo, and hair in the pangolin. The armor of reptiles like turtles and Ankylosaurs is constructed of bone, crocodiles have bony scutes, since exoskeletons are rigid, they present some limits to growth. Organisms with open shells can grow by adding new material to the aperture of their shell, as is the case in snails, bivalves, a true exoskeleton, like that found in arthropods, must be shed when it is outgrown. A new exoskeleton is produced beneath the old one, as the old one is shed, the new skeleton is soft and pliable. The animal will pump itself up to expand the new shell to maximal size, when the shell has set, the empty space inside the new skeleton can be filled up as the animal eats. Failure to shed the exoskeleton once outgrown can result in the animal being suffocated within its own shell and this is the mechanism behind some insect pesticides, such as Azadirachtin
41.
Stratigraphy
–
Stratigraphy is a branch of geology which studies rock layers and layering. It is primarily used in the study of sedimentary and layered volcanic rocks, stratigraphy has two related subfields, lithologic stratigraphy or lithostratigraphy, and biologic stratigraphy or biostratigraphy. The first practical application of stratigraphy was by William Smith in the 1790s. Another influential application of stratigraphy in the early 19th century was a study by Georges Cuvier, variation in rock units, most obviously displayed as visible layering, is due to physical contrasts in rock type. This variation can occur vertically as layering, or laterally, and these variations provide a lithostratigraphy or lithologic stratigraphy of the rock unit. Key concepts in stratigraphy involve understanding how certain geometric relationships between rock layers arise and what these geometries imply about their original depositional environment. The basic concept in stratigraphy, called the law of superposition, states, in a stratigraphic sequence. Chemostratigraphy studies the changes in the proportions of trace elements and isotopes within. Carbon and oxygen isotope ratios vary with time, and researchers can use those to map subtle changes that occurred in the paleoenvironment and this has led to the specialized field of isotopic stratigraphy. Biostratigraphy or paleontologic stratigraphy is based on evidence in the rock layers. Strata from widespread locations containing the fossil fauna and flora are said to be correlatable in time. Biologic stratigraphy was based on William Smiths principle of succession, which predated. It provides strong evidence for the formation and extinction of species, the geologic time scale was developed during the 19th century, based on the evidence of biologic stratigraphy and faunal succession. One important development is the Vail curve, which attempts to define a global historical sea-level curve according to inferences from worldwide stratigraphic patterns, stratigraphy is also commonly used to delineate the nature and extent of hydrocarbon-bearing reservoir rocks, seals, and traps of petroleum geology. Chronostratigraphy is the branch of stratigraphy that places an absolute age, a gap or missing strata in the geological record of an area is called a stratigraphic hiatus. This may be the result of a halt in the deposition of sediment, alternatively, the gap may be due to removal by erosion, in which case it may be called a stratigraphic vacuity. It is called a hiatus because deposition was on hold for a period of time, a physical gap may represent both a period of non-deposition and a period of erosion. A geologic fault may cause the appearance of a hiatus, magnetostratigraphy is a chronostratigraphic technique used to date sedimentary and volcanic sequences
42.
Bishop Tuff
–
The Bishop Tuff is a welded tuff that formed 767,100 ±900 years ago as a rhyolitic pyroclastic flow during the eruption that created the Long Valley Caldera. Large outcrops of the tuff are located in Inyo and Mono Counties, California, the Bishop Tuff caps a volcanic plateau in the northern Owens Valley. The tableland formation is located east of U. S. Route 395 and west of the Nevada stateline, sitting northwest of Bishop and southeast of Crowley Lake, another part of the flow is south of Mono Lake, and surrounding the Mono-Inyo Craters. Deposits of Bishop Tuff in this area cover nearly 2, 200-square-kilometer, the Owens River cut through the volcanic plateau, creating the Owens River Gorge. One of the monsters from the 1990 film Tremors exits from the Bishop Tuff close to Bishop Glass Mountain Long Valley Observatory - Bishop Tuff BLM Bishop Field Office web page
43.
California
–
California is the most populous state in the United States and the third most extensive by area. Located on the western coast of the U. S, California is bordered by the other U. S. states of Oregon, Nevada, and Arizona and shares an international border with the Mexican state of Baja California. Los Angeles is Californias most populous city, and the second largest after New York City. The Los Angeles Area and the San Francisco Bay Area are the nations second- and fifth-most populous urban regions, California also has the nations most populous county, Los Angeles County, and its largest county by area, San Bernardino County. The Central Valley, an agricultural area, dominates the states center. What is now California was first settled by various Native American tribes before being explored by a number of European expeditions during the 16th and 17th centuries, the Spanish Empire then claimed it as part of Alta California in their New Spain colony. The area became a part of Mexico in 1821 following its war for independence. The western portion of Alta California then was organized as the State of California, the California Gold Rush starting in 1848 led to dramatic social and demographic changes, with large-scale emigration from the east and abroad with an accompanying economic boom. If it were a country, California would be the 6th largest economy in the world, fifty-eight percent of the states economy is centered on finance, government, real estate services, technology, and professional, scientific and technical business services. Although it accounts for only 1.5 percent of the states economy, the story of Calafia is recorded in a 1510 work The Adventures of Esplandián, written as a sequel to Amadis de Gaula by Spanish adventure writer Garci Rodríguez de Montalvo. The kingdom of Queen Calafia, according to Montalvo, was said to be a land inhabited by griffins and other strange beasts. This conventional wisdom that California was an island, with maps drawn to reflect this belief, shortened forms of the states name include CA, Cal. Calif. and US-CA. Settled by successive waves of arrivals during the last 10,000 years, various estimates of the native population range from 100,000 to 300,000. The Indigenous peoples of California included more than 70 distinct groups of Native Americans, ranging from large, settled populations living on the coast to groups in the interior. California groups also were diverse in their organization with bands, tribes, villages. Trade, intermarriage and military alliances fostered many social and economic relationships among the diverse groups, the first European effort to explore the coast as far north as the Russian River was a Spanish sailing expedition, led by Portuguese captain Juan Rodríguez Cabrillo, in 1542. Some 37 years later English explorer Francis Drake also explored and claimed a portion of the California coast in 1579. Spanish traders made unintended visits with the Manila galleons on their trips from the Philippines beginning in 1565
44.
Pumice
–
Pumice, called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker walls and being dark colored. Pumice is created when super-heated, highly pressurized rock is violently ejected from a volcano, the unusual foamy configuration of pumice happens because of simultaneous rapid cooling and rapid depressurization. The depressurization creates bubbles by lowering the solubility of gases that are dissolved in the lava, the simultaneous cooling and depressurization freezes the bubbles in a matrix. Eruptions under water are cooled and the large volume of pumice created can be a shipping hazard for cargo ships. Pumice is composed of highly microvesicular glass pyroclastic with very thin and it is commonly, but not exclusively of silicic or felsic to intermediate in composition, but basaltic and other compositions are known. Pumice is commonly pale in color, ranging from white, cream, blue or grey and it forms when volcanic gases exsolving from viscous magma form bubbles that remain within the viscous magma as it cools to glass. Pumice is a product of explosive eruptions and commonly forms zones in upper parts of silicic lavas. Pumice has a porosity of 90%, and initially floats on water. Scoria differs from pumice in being denser, with larger vesicles and thicker vesicle walls, it sinks rapidly. The difference is the result of the viscosity of the magma that forms scoria. When larger amounts of gas are present, the result is a variety of pumice known as pumicite. Pumice is considered a glass because it has no crystal structure, pumice varies in density according to the thickness of the solid material between the bubbles, many samples float in water. After the explosion of Krakatoa, rafts of pumice drifted through the Pacific Ocean for up to 20 years, in fact, pumice rafts disperse and support several marine species. In 1979,1984 and 2006, underwater volcanic eruptions near Tonga created large pumice rafts, there are two main forms of vesicles. Most pumice contains tubular microvesicles that can impart a silky or fibrous fabric, the elongation of the microvesicles occurs due to ductile elongation in the volcanic conduit or, in the case of pumiceous lavas, during flow. The other form of vesicles are subspherical to spherical and result from high pressure during eruption. Pumice is widely used to make concrete or insulative low-density cinder blocks
This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Tuff". Encyclopædia Britannica (11th ed.). Cambridge University Press.
