1.
Mount Mazama
–
Mount Mazama is a stratovolcano in the Oregon segment of the Cascade Volcanic Arc and the Cascade Range located in the United States. The volcanos collapsed caldera holds Crater Lake, and the mountain is located within Crater Lake National Park. Its caldera was created by an eruption 42 times greater than the one of Mount St. Helens in 1980, Mazamas summit was destroyed by a volcanic eruption that occurred around 5677 BC, ±150 years. The eruption reduced Mazamas approximate 12, 000-foot height by about 1 mile, much of the volcano fell into the volcanos partially emptied neck and magma chamber. At 8,159 feet, Hillman Peak is now the highest point on the rim, the Klamath Native Americans of the area believed that the mountain was inhabited by Llao, their god of the underworld. After the mountain destroyed itself the Klamaths recounted the events as a battle between Llao and his rival Skell, their sky god. Mazama started to grow around 400,000 years ago in the Pleistocene and these early flows averaged 20 to 30 feet thick and appear to have been emplaced over a few years to a few centuries. Several shield volcanoes were created by these flows and numerous cinder cones grew in the immediate area, more explosive eruptions started around 75,000 years ago and built a westward-trending line of composite cones. Cone building eruptions lasted until around 50,000 years ago when lava flowed down Mazamas north. Relatively few of the cone building eruptions issued from the vent, resulting in a highly complex, approximately 11, 000-foot structure made of overlapping composite cones. Consequently, Mazamas base was broader and its sides not as steep as todays Mount Shasta, after its cone building phase, Mazama lavas became increasingly silica-rich and viscous - two conditions that tend to trap explosive gases. The first major eruption in this new cycle of Mazamas life occurred about 10,000 years later and these structures were subsequently destroyed by either collapse or steam explosions. Either way, their destruction created large landslides that left deposits at the head of Munson Valley, Mazamas next major eruptive period occurred between 25,000 and 30,000 years ago and extruded rhyodacite lava. These thick, slow moving, pasty flows erupted from a vent on Mazamas northeast flank and solidified to form 600-foot high Redcloud Cliff, the volcano then went dormant for roughly the next 20,000 years, while successive ice age glaciers cut large valleys into the mountains sides. One of the largest glaciers flowed down Munson Valley near the present location of headquarters, down Annie Creek Valley. When the last ice age ended 12,000 years ago, while Mazama slept, its magma chamber was going through some differentiation, with lighter, more gas- and silica-rich rocks collecting closer to the surface. Around 5677 BC Mazama awoke from its slumber with explosive eruptions on the northern part of the main summit where Llao Rock now resides. Great quantities of pumice and ash were ejected as a crater was excavated by the explosions
Mount Mazama
–
Mount Mazama collapsed into a caldera, which was filled with water to form
Crater Lake.
Mount Mazama
–
Aerial view of Crater Lake.
Mount Mazama
–
USGS Bathymetry Survey.
Mount Mazama
–
Hillman Peak
2.
Cauldron
–
A cauldron is a large metal pot for cooking and/or boiling over an open fire, with a large mouth and frequently with an arc-shaped hanger. The word cauldron is first recorded in Middle English as caudroun and it was borrowed from Norman caudron. It represents the evolution of Vulgar Latin *caldario for Classical Latin caldārium hot bath. The Norman-French word replaces probably the not initial new English sentence ċetel, the word kettle is a borrowing of the Old Norse variant ketill cauldron. Cauldrons have largely fallen out of use in the world as cooking vessels. In fiction, witches often prepare their potions in a cauldron, also, in Irish folklore, a cauldron is purported to be where leprechauns keep their gold and treasure. In some forms of Wicca, incorporating aspects of Celtic mythology, welsh legend also tells of cauldrons that were useful to warring armies. It was suspected that they lacked souls and these warriors could go back into battle until they were killed again. In Wicca and some forms of neopagan or pagan belief systems the cauldron is still used in magical practices. Most often a cauldron is made of cast iron and is used to burn incense on a charcoal disc, to make black salt, for mixing herbs. Cauldrons symbolize not only the Goddess but also represent the womb, cauldrons are often sold in New Age or metaphysical stores and may have various symbols of power inscribed on them. This may have resulted from the combination of the legend with earlier Celtic myths of magical cauldrons. The common translation for ding is often referred to as a cauldron, in Chinese history and culture, possession of one or more ancient dings is often associated with power and dominion over the land. Therefore, the ding is often used as a symbolism for power. The term inquiring of the ding is often used interchangeably with the quest for power
Cauldron
–
Hungarian
goulash in a traditional "bogrács" (cauldron)
Cauldron
–
A cauldron over a fire in
William Blake 's illustrations to his mythical
Europe a Prophecy first published in 1794. This version of the print is currently held by the
Fitzwilliam Museum
Cauldron
–
A
Bronze Age cauldron made from sheet
bronze and a
flesh-hook
Cauldron
–
A Witches'-caldron table
3.
Depression (geology)
–
A depression in geology is a landform sunken or depressed below the surrounding area. Erosion-related, Blowout, a depression created by wind erosion typically in either a partially vegetated sand dune ecosystem or dry soils, glacial valley, a depression carved by erosion by a glacier. River valley, a depression carved by erosion by a river. Area of subsidence caused by the collapse of a structure such as sinkholes in karst terrain. Sink, an endorheic depression generally containing a persistent or intermittent lake, collapse-related, Sinkhole, a depression formed as a result of the collapse of rocks lying above a hollow. This is common in karst regions, kettle, a shallow, sediment-filled body of water formed by melting glacial remnants in terminal moraines. Thermokarst hollow, caused by loss of the ground as the result of permafrost thawing. Impact-related, Impact crater, a depression created by an impact such as a meteorite crater, sedimentary-related, Sedimentary basin, in sedimentology, an area thickly filled with sediment in which the weight of the sediment further depresses the floor of the basin. Structural or tectonic-related, Structural basin, a depression, a region of tectonic downwarping as a result of isostasy or subduction. Graben or rift valley, fallen and typically linear depressions or basins created by rifting in a region under tensional tectonic forces, pull-apart basin caused by offset in a strike slip or transform fault. Oceanic trench, a linear depression on the ocean floor. Oceanic trenches are caused by subduction of oceanic crust beneath either oceanic crust or continental crust, pit crater, a volcanic depression smaller than a caldera formed by a sinking, or caving in, of the ground surface lying over a void. Maar, a resulting from phreatomagmatic eruption or diatreme explosion. Cryptodepression List of places on land with elevations below sea level
Depression (geology)
–
A watering hole is a depression where water collects and animals come to drink
4.
Magma chamber
–
A magma chamber is a large underground pool of liquid rock found beneath the surface of the Earth. The molten rock in such a chamber is under pressure, and given enough time. If it finds a way to the surface, then the result will be a volcanic eruption, magma chambers are hard to detect, and most of the known ones are therefore close to the surface of the Earth, commonly between 1 km and 10 km under the surface. In geological terms, this is close to the surface, although in human terms. Magma rises through cracks from beneath and across the crust because it is less dense than the surrounding rock, when the magma cannot find a path upwards it pools into a magma chamber. Magma chambers are built up incrementally, by successive horizontal or vertical magma injections. Influx of new magma causes reaction of pre-existing crystals and the pressure in the chamber to increase, upon cooling, new mineral phases saturate and the rock type changes, typically forming gabbro, diorite, tonalite and granite or gabbro, diorite, syenite and granite. If magma resides in a chamber for a period, then it can become stratified with lower density components rising to the top. Rocks accumulate in layers, forming a layered intrusion, additionally, the removal of the lower melting point components will tend to make the magma more viscous. If the magma is not vented to the surface in an eruption, it will slowly cool. Often, a volcano may have a deep magma chamber many kilometers down, as a volcano erupts, emptying the magma chamber, the surrounding rock will collapse into it. If a large amount of magma is erupted, causing the chamber to reduce considerably in volume, then this can result in a depression at the surface called a caldera
Magma chamber
–
11 - magma chamber
5.
Volcanic crater
–
A volcanic crater is a roughly circular depression in the ground caused by volcanic activity. It is typically a bowl-shaped feature within which occurs a vent or vents, a volcanic crater can be of large dimensions, and sometimes of great depth. During certain types of eruptions, a volcanos magma chamber may empty enough for an area above it to subside. In most volcanoes, the crater is situated at the top of a formed from the erupted volcanic deposits such as lava flows. Volcanoes that terminate in such a summit crater are usually of a conical form, other volcanic craters may be found on the flanks of volcanoes, and these are commonly referred to as flank craters. Some volcanic craters may fill either fully or partially with rain and/or melted snow, a crater may be breached during an eruption, either by explosions or by lava, or through later erosion. Breached craters have a lower rim on one side. Some volcanoes, such as maars, consist of a crater alone and these volcanic explosion craters are formed when magma rises through water-saturated rocks and causes a phreatic eruption. Volcanic craters from phreatic eruptions often occur on plains away from other obvious volcanoes
Volcanic crater
–
Craters on
Mount Cameroon
Volcanic crater
–
The volcanic crater of a
Tangkuban Parahu mount,
Bandung,
Indonesia
Volcanic crater
–
The crater in
Santa Ana Volcano,
El Salvador.
Volcanic crater
–
Volcán Irazú,
Costa Rica
6.
Sinkhole
–
A sinkhole, also known as a cenote, sink, sink-hole, shakehole, swallet, swallow hole, or doline, is a depression or hole in the ground caused by some form of collapse of the surface layer. Most are caused by karst processes—for example, the dissolution of carbonate rocks or suffosion processes. Sinkholes vary in size from 1 to 600 m both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms, sinkholes may form gradually or suddenly, and are found worldwide. Sinkholes may capture surface drainage from running or standing water, but may form in high. Sinkholes that capture drainage can hold it in limestone caves. These caves may drain into tributaries of larger rivers, the formation of sinkholes involves natural processes of erosion or gradual removal of slightly soluble bedrock by percolating water, the collapse of a cave roof, or a lowering of the water table. Sinkholes often form through the process of suffosion, for example, groundwater may dissolve the carbonate cement holding the sandstone particles together and then carry away the lax particles, gradually forming a void. Occasionally a sinkhole may exhibit a visible opening into a cave below, sinkholes also occur in sandstone and quartzite terrains. As the rock dissolves, spaces and caverns develop underground and these sinkholes can be dramatic, because the surface land usually stays intact until there is not enough support. Then, a collapse of the land surface can occur. Sinkholes also form from human activity, such as the collapse of abandoned mines and salt cavern storage in salt domes in places like Louisiana, Mississippi, more commonly, sinkholes occur in urban areas due to water main breaks or sewer collapses when old pipes give way. They can also occur from the overpumping and extraction of groundwater, sinkholes can also form when natural water-drainage patterns are changed and new water-diversion systems are developed. Sinkholes tend to occur in karst landscapes, karst landscapes can have up to thousands of sinkholes within a small area, giving the landscape a pock-marked appearance. These sinkholes drain all the water, so there are only subterranean rivers in these areas, examples of karst landscapes with a plethora of massive sinkholes include Khammouan Mountains and Mamo Plateau. The largest known sinkholes formed in sandstone are Sima Humboldt and Sima Martel in Venezuela, some sinkholes form in thick layers of homogenous limestone. On the contact of limestone and insoluble rock below it, powerful underground rivers may form, in such conditions, the largest known sinkholes of the world have formed, like the 662-metre deep Xiaozhai Tiankeng, giant sótanos in Querétaro and San Luis Potosí states in Mexico and others. The state of Florida in the United States is known for having frequent sinkhole collapses, the Murge area in southern Italy also has numerous sinkholes. Sinkholes can be formed in retention ponds from large amounts of rain, an analysis of a case of sinkhole formation under a retention pond due to a large amount of rain can be seen in a sinkhole collapse study
Sinkhole
–
The
Red Lake sinkhole in
Croatia
Sinkhole
–
Sinkholes near the
Dead Sea, formed when underground salt is dissolved by freshwater intrusion, due to continuing sea-level drop.
Sinkhole
–
Sinkhole formed by rainwater leaking through pavement and carrying soil into a ruptured sewer pipe.
Sinkhole
–
The entire
surface water flow of the
Alapaha River near
Jennings, Florida goes into a sinkhole leading to the
Floridan Aquifer groundwater
7.
Spanish language
–
Spanish —also called Castilian —is a Romance language that originated in the Castile region of Spain, with hundreds of millions of native speakers around the world. It is usually considered the worlds second-most spoken native language after Mandarin Chinese and it is one of the few languages to use inverted question and exclamation marks. Spanish is a part of the Ibero-Romance group of languages, which evolved from several dialects of Vulgar Latin in Iberia after the collapse of the Western Roman Empire in the 5th century. Beginning in the early 16th century, Spanish was taken to the colonies of the Spanish Empire, most notably to the Americas, as well as territories in Africa, Oceania, around 75% of modern Spanish is derived from Latin. Greek has also contributed substantially to Spanish vocabulary, especially through Latin, Spanish vocabulary has been in contact from an early date with Arabic, having developed during the Al-Andalus era in the Iberian Peninsula. With around 8% of its vocabulary being Arabic in origin, this language is the second most important influence after Latin and it has also been influenced by Basque as well as by neighboring Ibero-Romance languages. It also adopted words from languages such as Gothic language from the Visigoths in which many Spanish names and surnames have a Visigothic origin. Spanish is one of the six languages of the United Nations. It is the language in the world by the number of people who speak it as a mother tongue, after Mandarin Chinese. It is estimated more than 437 million people speak Spanish as a native language. Spanish is the official or national language in Spain, Equatorial Guinea, speakers in the Americas total some 418 million. In the European Union, Spanish is the tongue of 8% of the population. Spanish is the most popular second language learned in the United States, in 2011 it was estimated by the American Community Survey that of the 55 million Hispanic United States residents who are five years of age and over,38 million speak Spanish at home. The Spanish Constitution of 1978 uses the term castellano to define the language of the whole Spanish State in contrast to las demás lenguas españolas. Article III reads as follows, El castellano es la lengua española oficial del Estado, las demás lenguas españolas serán también oficiales en las respectivas Comunidades Autónomas. Castilian is the official Spanish language of the State, the other Spanish languages as well shall be official in their respective Autonomous Communities. The Spanish Royal Academy, on the hand, currently uses the term español in its publications. Two etymologies for español have been suggested, the Spanish Royal Academy Dictionary derives the term from the Provençal word espaignol, and that in turn from the Medieval Latin word Hispaniolus, from—or pertaining to—Hispania
Spanish language
–
A page of
Cantar de Mio Cid, the oldest preserved Spanish
epic poem, in medieval Spanish.
Spanish language
–
Spanish is sole official language at the national level
Spanish language
–
Antonio de Nebrija, author of
Gramática de la lengua castellana, the first grammar of modern European languages.
Spanish language
–
Miguel de Cervantes author of
Don Quixote, considered the first modern European novel.
8.
Latin
–
Latin is a classical language belonging to the Italic branch of the Indo-European languages. The Latin alphabet is derived from the Etruscan and Greek alphabets, Latin was originally spoken in Latium, in the Italian Peninsula. Through the power of the Roman Republic, it became the dominant language, Vulgar Latin developed into the Romance languages, such as Italian, Portuguese, Spanish, French, and Romanian. Latin, Italian and French have contributed many words to the English language, Latin and Ancient Greek roots are used in theology, biology, and medicine. By the late Roman Republic, Old Latin had been standardised into Classical Latin, Vulgar Latin was the colloquial form spoken during the same time and attested in inscriptions and the works of comic playwrights like Plautus and Terence. Late Latin is the language from the 3rd century. Later, Early Modern Latin and Modern Latin evolved, Latin was used as the language of international communication, scholarship, and science until well into the 18th century, when it began to be supplanted by vernaculars. Ecclesiastical Latin remains the language of the Holy See and the Roman Rite of the Catholic Church. Today, many students, scholars and members of the Catholic clergy speak Latin fluently and it is taught in primary, secondary and postsecondary educational institutions around the world. The language has been passed down through various forms, some inscriptions have been published in an internationally agreed, monumental, multivolume series, the Corpus Inscriptionum Latinarum. Authors and publishers vary, but the format is about the same, volumes detailing inscriptions with a critical apparatus stating the provenance, the reading and interpretation of these inscriptions is the subject matter of the field of epigraphy. The works of several hundred ancient authors who wrote in Latin have survived in whole or in part and they are in part the subject matter of the field of classics. The Cat in the Hat, and a book of fairy tales, additional resources include phrasebooks and resources for rendering everyday phrases and concepts into Latin, such as Meissners Latin Phrasebook. The Latin influence in English has been significant at all stages of its insular development. From the 16th to the 18th centuries, English writers cobbled together huge numbers of new words from Latin and Greek words, dubbed inkhorn terms, as if they had spilled from a pot of ink. Many of these words were used once by the author and then forgotten, many of the most common polysyllabic English words are of Latin origin through the medium of Old French. Romance words make respectively 59%, 20% and 14% of English, German and those figures can rise dramatically when only non-compound and non-derived words are included. Accordingly, Romance words make roughly 35% of the vocabulary of Dutch, Roman engineering had the same effect on scientific terminology as a whole
Latin
–
Latin inscription, in the
Colosseum
Latin
–
Julius Caesar 's
Commentarii de Bello Gallico is one of the most famous classical Latin texts of the Golden Age of Latin. The unvarnished, journalistic style of this
patrician general has long been taught as a model of the urbane Latin officially spoken and written in the floruit of the
Roman republic.
Latin
–
A multi-volume Latin dictionary in the
University Library of Graz
Latin
–
Latin and Ancient Greek Language - Culture - Linguistics at
Duke University in 2014.
9.
Leopold von Buch
–
His scientific interest was devoted to a broad spectrum of geological topics, volcanism, fossils, stratigraphy and more. His most remembered accomplishment is the definition of the Jurassic system. He was known as Leopold von Buch, Buch studied with Alexander von Humboldt under Abraham Gottlob Werner at the mining school in Freiberg, Saxony. He afterwards completed his education at the universities of Halle and Göttingen and he began writing on geological topics early in life. His Versuch einer mineralogischen Beschreibung von Landeck was translated into French, in 1802 he published Entwurf einer geognostischen Beschreibung von Schlesien, which became the first volume of his Geognostische Beobachtungen auf Reisen durch Deutschland und Italien. He was at time a zealous upholder of the Neptunian theory of Werner. In 1797, he met Humboldt at Salzburg, and with him explored the geological formations of Styria, in the spring of 1798, Buch extended his excursions into Italy, where his faith in the Neptunian theory was shaken. In his early works, he had advocated the aqueous origin of basaltic and other formations, but now he saw cause to abandon Werners theory and he saw Vesuvius for the first time in 1799. Later, in 1805, he had the opportunity, along with Humboldt and Gay Lussac and it was a remarkable eruption, and supplied Buch with data for refuting many erroneous ideas then entertained regarding volcanoes. In 1802 he examined the extinct volcanoes of the Auvergne in the south of France. The aspect of the Puy de Dôme, with its cone of trachyte and its strata of basaltic lava, the results of all these geological travels were given to the world in the two volumes of his Geognostische Beobachtungen. In 1806, Buch proceeded to Scandinavia and spent two years in examining its physical constitution and this furnished the materials for his work entitled Reise durch Norwegen und Lappland. He made many important observations on the geography of plants, on climatology and he showed that many of the erratic blocks on the North German plains must have come from Scandinavia. He also established the fact that the whole of Sweden is slowly but continuously rising above the level of the sea from Frederikshald to Abo, in 1815 Buch visited the Canary Islands in company with Christen Smith, a Norwegian botanist. These volcanic isles furnished the starting point from which Buch commenced a course of study on the production. This is attested by his work on the subject entitled Physical Description of the Canary Isles. During his time in the Canary Islands, he visited the Las Cañadas Caldera on Tenerife, when he published his memoirs and observations about his excursion, he introduced the Spanish word Caldera into the geological and scientific vocabulary. After his return from the Canaries he visited the group of the Hebrides
Leopold von Buch
–
Christian Leopold von Buch, by
Carl Joseph Begas (1850)
Leopold von Buch
–
Statue, sculpted by Richard Ohmann
10.
Canary Islands
–
The Canary Islands, also known as the Canaries, are an archipelago and autonomous community of Spain located on the Atlantic Ocean,100 kilometres west of Morocco. The Canaries are among the outermost regions of the European Union proper and it is also one of the eight regions with special consideration of historical nationality recognized as such by the Spanish Government. The main islands are Tenerife, Fuerteventura, Gran Canaria, Lanzarote, La Palma, La Gomera, the archipelago also includes a number of islands and islets, La Graciosa, Alegranza, Isla de Lobos, Montaña Clara, Roque del Oeste and Roque del Este. In ancient times, the chain was often referred to as the Fortunate Isles. The Canary Islands is the most southerly region of Spain and the largest and most populated archipelago of the Macaronesia region, the islands have a subtropical climate, with long hot summers and moderately warm winters. The precipitation levels and the level of maritime moderation varies depending on location and elevation, green areas as well as desert exist on the archipelago. Due to their location above the inversion layer, the high mountains of these islands are ideal for astronomical observation. For this reason, two professional observatories, Teide Observatory on the island of Tenerife and Roque de los Muchachos Observatory on the island of La Palma, have built on the islands. Las Palmas de Gran Canaria has been the largest city in the Canaries since 1768, between the 1833 territorial division of Spain and 1927 Santa Cruz de Tenerife was the sole capital of the Canary Islands. In 1927 a decree ordered that the capital of the Canary Islands be shared, the third largest city of the Canary Islands is San Cristóbal de La Laguna on Tenerife. This city is home to the Consejo Consultivo de Canarias. During the time of the Spanish Empire, the Canaries were the main stopover for Spanish galleons on their way to the Americas, who came south to catch the prevailing northeasterly trade winds. The name Islas Canarias is likely derived from the Latin name Canariae Insulae, meaning Islands of the Dogs, according to the historian Pliny the Elder, the Mauretanian king Juba II named the island Canaria because it contained vast multitudes of dogs of very large size. Another speculation is that the dogs were actually a species of monk seal, critically endangered. The dense population of seals may have been the characteristic that most struck the few ancient Romans who established contact with these islands by sea. Alternatively, it is said that the inhabitants of the island, Guanches, used to worship dogs, mummified them. The ancient Greeks also knew about a people, living far to the west, who are the dog-headed ones, who worshipped dogs on an island. Some hypothesize that the Canary Islands dog-worship and the ancient Egyptian cult of the god, Anubis are closely connected
Canary Islands
–
Mount
Teide on
Tenerife, the highest mountain in Spain, is also one of the most visited
National Parks in the world.
Canary Islands
–
Flag
Canary Islands
–
Hacha Grande, a mountain in the south of Lanzarote, viewed from the road to the Playa de Papagayo.
Canary Islands
–
Panoramic view of Gran Canaria, with
Roque Nublo at the left and Roque Bentayga at the center
11.
Teide
–
Mount Teide is a volcano on Tenerife in the Canary Islands, Spain. Its 3, 718-metre summit is the highest point in Spain, if measured from the ocean floor, it is at 7,500 m the highest volcano in the world base-to-peak outside of the Hawaiian Islands. Its elevation makes Tenerife the tenth highest island in the world and it remains active, its most recent eruption occurred in 1909 from the El Chinyero vent on the northwestern Santiago rift. Teide, Pico Viejo and Montaña Blanca form the Central Volcanic Complex of Tenerife, the volcano and its surroundings comprise Teide National Park, which has an area of 18,900 hectares and was named a World Heritage Site by UNESCO on June 28,2007. Teide is the most visited natural wonder of Spain, the most visited park in Spain and Europe and – by 2015 – the eighth most visited in the world. A major international astronomical observatory is located on the slopes of the mountain, before the 1495 Spanish colonization of Tenerife, the native Guanches called the volcano Echeyde, which in their legends referred to a powerful figure leaving the volcano, which could turn into hell. El Pico del Teide is the modern Spanish name, Teide was a sacred mountain for the aboriginal Guanches, so it was considered a mythological mountain, as Mount Olympus was to the ancient Greeks. According to legend, Guayota kidnapped Magec and imprisoned him inside the volcano, the Guanches asked their supreme god Achamán for clemency, so Achamán fought Guayota, freed Magec from the bowels of the mountain, and plugged the crater with Guayota. It is said that then, Guayota has remained locked inside Teide. When going on to Teide during an eruption, it was customary for the Guanches to light bonfires to scare Guayota, Guayota is often represented as a black dog, accompanied by his host of demons. The Guanches also believed that Teide held up the sky, many hiding places found in the mountains contain the remains of stone tools and pottery. These have been interpreted as being ritual deposits to counter the influence of evil spirits, the Guanches believed the mountain to be the place that housed the forces of evil and the most evil figure, Guayota. The stratovolcanoes Teide and Pico Viejo are the most recent centres of activity on the island of Tenerife. It has a complex volcanic history, the formation of the island and the development of the current Teide volcano took place in the five stages shown in the diagram on the right. Like the other Canary Islands, and volcanic islands in general. This early shield stage volcanism formed the bulk of the part of Tenerife. The shield volcanoes date back to the Miocene and early Pliocene and are preserved in three isolated and deeply eroded massifs, Anaga, Teno and Roque del Conde, each shield was apparently constructed in less than three million years, and the entire island in about eight million years. The initial juvenile stage was followed by a period of 2–3 million years of eruptive quiescence and this cessation of activity is typical of the Canaries, La Gomera, for example, is currently at this stage
Teide
–
Teide seen from the north
Teide
–
Echium wildpretii on Tenerife
Teide
–
Southern Tenerife lizard (Gallotia galloti galloti)
Teide
–
Teide and
Roque Cinchado
12.
Caldera de Taburiente
–
Caldera de Taburiente National Park is a national park on the island of La Palma, Canary Islands, Spain. It was designated as a park in 1954. The caldera is about 10 km across, and in places the walls tower 2000 m over the caldera floor, the highest point is the Roque de los Muchachos on the northern wall, at 2426 m altitude, which can be reached by road. The telescopes of the Roque de los Muchachos Observatory are situated close to the summit. It proved impregnable to the invading Spaniards, and they defeated the Benahoarita by luring their leader out on the pretext of holding talks. The Cumbrecita is at a point in the south-eastern part of the calderas rim. In the south-west the caldera opens to the sea, through a known as Barranco de las Augustias. The Cumbre Nueva is a ridge that starts at the caldera, the main flora of the national park comprises a large forest of Canary Island Pine, with important population of the endangered Canary Islands Juniper also present. The caldera originated some 2 million years ago, with a shield volcano about 20 km in diameter. The caldera was not formed by an explosion of that volcano however, the word caldera means cauldron in Spanish. In 1815 the great German geologist Christian Leopold von Buch visited the Canary Islands during which he visited the island of Tenerife where he was taken to the Caldera de las Cañadas. Following his return to Germany he published his journal and he introduced the term Caldera to the geological vocabulary, Taburiente is not a Spanish word but derives from the Guanche language and means plain, level
Caldera de Taburiente
–
Inside of the caldera
Caldera de Taburiente
–
Clouds covering a part of the caldera
Caldera de Taburiente
–
Looking from the edge of the caldera into a tributary valley
Caldera de Taburiente
–
A satellite picture of the Caldera de Taburiente. Barranco de las Angustias is in the upper right and Cumbre Nueva is in the upper left. (South is above and north is below.)
13.
La Palma
–
La Palma, also San Miguel de La Palma, is the most north-westerly island of the Canary Islands, Spain. La Palma has an area of 706 km2 making it the fifth largest of the seven main Canary Islands. The total population is about 86,000, of which 18,000 live in the capital, Santa Cruz de la Palma, La Palma has sister city status with El Dorado Hills, California. In 1815, the German geologist Leopold von Buch visited the Canary Islands, in the center of the island is the Caldera de Taburiente National Park, one of four national parks in the Canary Islands. La Palma, like the islands of the Canary Island archipelago, is a volcanic ocean island. The volcano rises almost 7 km above the floor of the Atlantic Ocean, there is road access from sea level to the summit at 2,426 m, which is marked by an outcrop of rocks called Los Muchachos. This is the site of the Roque de los Muchachos Observatory, La Palmas geography is a result of the volcanic formation of the island. The highest peaks reach over 2,400 m above sea level, the northern part of La Palma is dominated by the Caldera de Taburiente, with a width of 9 km and a depth of 1,500 m. It is surrounded by a ring of mountains ranging from 1,600 m to 2,400 m in height, on its northern side is the exposed remains of the original seamount. Only the deep Barranco de las Angustias ravine leads into the area of the caldera. It can be reached only by hiking, the outer slopes are cut by numerous gorges which run from 2,000 m down to the sea. Today, only few of these carry water due to the water tunnels that have been cut into the islands structure. From the Caldera de Taburiente to the runs the ridge Cumbre Nueva – the New Ridge. The southern part of La Palma consists of the Cumbre Vieja, the Cumbre Vieja is active – but dormant, with the last eruption occurring in 1971 at the Teneguía vent which is located at the southern end of the Cumbre Vieja – Punta de Fuencaliente. Beyond Punta de Fuencaliente, the Cumbre Vieja continues in a direction as a submarine volcano. Like all of the Canary Islands, La Palma originally formed as a seamount through submarine volcanic activity, La Palma is currently – along with Tenerife, the most volcanically active of the Canary Islands and was formed three to four million years ago. Its base lies almost 4,000 m below sea level, about a half a million years ago, the Taburiente volcano collapsed with a giant landslide, forming the Caldera de Taburiente. Erosion has since exposed part of the seamount in the sector of the Caldera
La Palma
–
Satellite image of La Palma, with the Caldera de Taburiente visible (north is to the lower right)
La Palma
–
Flag of La Palma
La Palma
–
A view of the island looking south
La Palma
–
Walls of
Caldera de Taburiente
14.
Landsat
–
The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. On July 23,1972 the Earth Resources Technology Satellite was launched and this was eventually renamed to Landsat. The most recent, Landsat 8, was launched on February 11,2013, the instruments on the Landsat satellites have acquired millions of images. Landsat 7 data has eight spectral bands with spatial resolutions ranging from 15 to 60 meters, Landsat images are usually divided into scenes for easy downloading. Each Landsat scene is about 115 miles long and 115 miles wide, Hughes Santa Barbara Research Center initiated, designed, and fabricated the first three Multispectral Scanners in 1969, the same year man landed on the moon. The first prototype MSS was completed nine months, in the fall of 1970. It was tested by scanning Half Dome at Yosemite National Park, the program was initially called the Earth Resources Technology Satellites Program, which was used from 1966 to 1975. In 1975, the name was changed to Landsat and this occurred in 1985 when the Earth Observation Satellite Company, a partnership of Hughes Aircraft and RCA, was selected by NOAA to operate the Landsat system with a ten-year contract. EOSAT operated Landsat 4 and Landsat 5, had rights to market Landsat data. In 1989, this transition had not been completed when NOAAs funding for the Landsat program was due to run out. The head of the newly formed National Space Council, Vice President Dan Quayle, noted the situation and arranged emergency funding that allowed the program to continue with the data archives intact. Again in 1990 and 1991, Congress provided only half of the funding to NOAA. In 1992, various efforts were made to procure funding for follow on Landsats and continued operations, Landsat 6 was finally launched on October 5,1993, but was lost in a launch failure. Processing of Landsat 4 and 5 data was resumed by EOSAT in 1994, NASA finally launched Landsat 7 on April 15,1999. Timeline Landsat missions 1 through 5 carried the Landsat Multispectral Scanner and this construct ensured the secondary mirror would simply oscillate about the primary optic axis to maintain focus despite vibration inherent from the 360 mm beryllium scan mirror. This engineering solution allowed the United States to develop LANDSAT at least five years ahead of the French SPOT and this was a direct result of the commercialization efforts begun under the Carter administration, though finally completed under the Reagan administration. This main plate was assembled on a frame, then attached to the magnesium housing with helicoil fasteners. Key to the success of the multi spectral scanner was the scan monitor mounted on the underbelly of the magnesium housing, the beam struck the beryllium scan mirror seven times as it reflected seven times off the flat mirrors
Landsat
–
Landsat 7, launched in 1999, is the second most recent addition to the Landsat program.
Landsat
–
A simulated-color satellite image of
Kolkata taken on NASA's Landsat 7 satellite.
Landsat
–
Landsat 1
15.
Lake Toba
–
Lake Toba is a large natural lake occupying the caldera of a supervolcano. The lake is about 100 kilometres long,30 kilometres wide and it is the largest lake in Indonesia and also the largest volcanic lake in the world. Lake Toba is the site of a massive supervolcanic eruption estimated at VEI8 that occurred 69,000 to 77,000 years ago and it is the largest known explosive eruption on Earth in the last 25 million years. It has been accepted that the eruption of Toba led to a winter with a worldwide decrease in temperature between 3 to 5 °C, and up to 15 °C in higher latitudes. The Toba caldera complex in Northern Sumatra, comprises four overlapping volcanic craters that adjoin the Sumatran volcanic front, the fourth and youngest caldera is the worlds largest Quaternary caldera and intersects the three older calderas. Following this eruption, a resurgent dome formed within the new caldera, at least four cones, four stratovolcanoes, and three craters are visible in the lake. The Tandukbenua cone on the edge of the caldera has only sparse vegetation. Also, the Pusubukit volcano on the edge of the caldera is solfatarically active and is a Geology Sanctuary. The Toba eruption occurred at what is now Lake Toba about 75000±900 years ago and it was the last in a series of at least four caldera-forming eruptions at this location, with earlier calderas having formed around 788000±2200 years ago. This last eruption had an estimated VEI=8, making it the largest known volcanic eruption within the last 25 million years. However, based on the new method, Toba possibly erupted 3200 km³ of ignimbrite and co-ignimbrite, the pyroclastic flows of the eruption destroyed an area of least 20,000 km2, with ash deposits as thick as 600 m by the main vent. In addition it has been calculated that 10,000 million tonnes of sulfurous acid or 6,000 million tonnes of sulfur dioxide were ejected into the atmosphere by the event. The subsequent collapse formed a caldera that, after filling with water, the island in the center of the lake is formed by a resurgent dome. The eruption lasted perhaps two weeks, and the ensuing volcanic winter resulted in a decrease in global temperatures by 3.0 to 3.5 °C for several years. Greenland ice cores record a pulse of starkly reduced levels of carbon sequestration. Very few plants or animals in southeast Asia would have survived, however, the global cooling has been discussed by Rampino and Self. Their conclusion is that the cooling had already started before Tobas eruption and this conclusion was supported by Lane and Zielinski who studied the lake-core from Africa and GISP2. They concluded that there was no volcanic winter after Toba eruption, however, this hypothesis is not widely accepted because similar effects on other animal species have not been observed, and paleoanthropology suggests there was no population bottleneck
Lake Toba
–
Lake Toba
Lake Toba
–
Batu Gantung (Hanging stone) in Lake Toba
Lake Toba
–
Landsat photo of Sumatra surrounding Lake Toba
Lake Toba
–
Batak canoes near Haranggaol on Lake Toba (circa 1920)
16.
Sumatra
–
Sumatra is a large island in western Indonesia that is part of the Sunda Islands. It is the largest island that is entirely in Indonesia and the sixth-largest island in the world at 473,481 km2, Sumatra is an elongated landmass spanning a diagonal northwest-southeast axis. The Indian Ocean borders the west, northwest, and southwest sides of Sumatra with the chain of Simeulue, Nias. On the northeast side the narrow Strait of Malacca separates the island from the Malay Peninsula, on the southeast the narrow Sunda Strait separates Sumatra from Java. The northern tip of Sumatra borders the Andaman Islands, while on the eastern side are the islands of Bangka and Belitung, Karimata Strait. The Bukit Barisan mountains, which several active volcanoes, form the backbone of the island, while the northeast sides are outlying lowlands with swamps, mangrove. The equator crosses the island at its center on West Sumatra, the climate of the island is tropical, hot and humid with lush tropical rain forest once dominating the landscape. Sumatra was known in ancient times by the Sanskrit names of Swarnadwīpa and Swarnabhūmi, the first word mentioning the name of Sumatra was the name of Srivijayan Haji Sumatrabhumi, who sent an envoy to China in 1017. Arab geographers referred to the island as Lamri in the tenth through thirteenth centuries, late in the 14th century the name Sumatra became popular in reference to the kingdom of Samudra Pasai, which was a rising power until it was replaced by Sultanate of Aceh. Sultan Alauddin Shah of Aceh, on letters written in 1602 addressed to Queen Elizabeth I of England, referred to himself as king of Aceh, the word itself is from Sanskrit Samudra, meaning gathering together of waters, sea or ocean. European writers in the 19th century found that the inhabitants did not have a name for the island. The Melayu Kingdom was absorbed by Srivijaya, Srivijaya was a Buddhist monarchy centred in what is now Palembang. Dominating the region trade and conquest throughout the 7th to 9th centuries. The empire was a thalassocracy or maritime power that extended its influence from island to island, Palembang was a center for scholarly learning, and it was there the Chinese Buddhist pilgrim I Ching studied Sanskrit in 671 CE before departing for India. On his journey to China, he spent four years in Palembang translating Buddhist texts, Srivijayan influence waned in the 11th century after it was defeated by the Chola Empire of southern India. At the same time, Islam made its way to Sumatra through Arabs, by the late 13th century, the monarch of the Samudra kingdom had converted to Islam. Marco Polo visited the island in 1292, and Ibn Battuta visited twice during 1345–1346, Samudra was succeeded by the powerful Aceh Sultanate, which survived to the 20th century. With the coming of the Dutch, the many Sumatran princely states fell under their control
Sumatra
–
Batak warriors, 1870
Sumatra
–
Topography of Sumatra
Sumatra
–
Traditional house in Nias North Sumatra
Sumatra
–
Rumah Gadang, Minangkabau traditional house in West Sumata
17.
Indonesia
–
Indonesia, officially the Republic of Indonesia, is a unitary sovereign state and transcontinental country located mainly in Southeast Asia with some territories in Oceania. Situated between the Indian and Pacific oceans, it is the worlds largest island country, with more than seventeen thousand islands. At 1,904,569 square kilometres, Indonesia is the worlds 14th-largest country in terms of area and worlds 7th-largest country in terms of combined sea. It has an population of over 260 million people and is the worlds fourth most populous country. The worlds most populous island, Java, contains more than half of the countrys population, Indonesias republican form of government includes an elected legislature and president. Indonesia has 34 provinces, of which five have Special Administrative status and its capital and countrys most populous city is Jakarta, which is also the most populous city in Southeast Asia and the second in Asia. The country shares land borders with Papua New Guinea, East Timor, other neighbouring countries include Singapore, Vietnam, the Philippines, Australia, Palau, and the Indian territory of the Andaman and Nicobar Islands. Despite its large population and densely populated regions, Indonesia has vast areas of wilderness that support the second highest level of biodiversity. The country has abundant natural resources like oil and natural gas, tin, copper, agriculture mainly produces rice, palm oil, tea, coffee, cacao, medicinal plants, spices and rubber. Indonesias major trading partners are Japan, United States, China, the Indonesian archipelago has been an important region for trade since at least the 7th century, when Srivijaya and then later Majapahit traded with China and India. Local rulers gradually absorbed foreign cultural, religious and political models from the early centuries CE, Indonesian history has been influenced by foreign powers drawn to its natural resources. Indonesia consists of hundreds of native ethnic and linguistic groups. The largest – and politically dominant – ethnic group are the Javanese, a shared identity has developed, defined by a national language, ethnic diversity, religious pluralism within a Muslim-majority population, and a history of colonialism and rebellion against it. Indonesias national motto, Bhinneka Tunggal Ika, articulates the diversity that shapes the country, Indonesias economy is the worlds 16th largest by nominal GDP and the 8th largest by GDP at PPP, the largest in Southeast Asia, and is considered an emerging market and newly industrialised country. Indonesia has been a member of the United Nations since 1950, Indonesia is a member of the G20 major economies and World Trade Organization. The name Indonesia derives from the Greek name of the Indós, the name dates to the 18th century, far predating the formation of independent Indonesia. In 1850, George Windsor Earl, an English ethnologist, proposed the terms Indunesians—and, his preference, in the same publication, one of his students, James Richardson Logan, used Indonesia as a synonym for Indian Archipelago. However, Dutch academics writing in East Indies publications were reluctant to use Indonesia, they preferred Malay Archipelago, the Netherlands East Indies, popularly Indië, the East, and Insulinde
Indonesia
–
A
Borobudur ship carved on
Borobudur, c. 800 CE. Indonesian outrigger boats may have made trade voyages to the east coast of Africa as early as the 1st century CE.
Indonesia
–
Flag
Indonesia
–
The
nutmeg plant is native to Indonesia's
Banda Islands.
Indonesia
–
Tan Malaka, Indonesian philosopher, guerilla, and national hero.
18.
Samosir
–
For the Regency named Samosir, see Samosir Regency. Samosir, or Samosir Island, is a volcanic island in Lake Toba. Administratively, Samosir Island is governed as six of the nine districts within Samosir Regency, the lake and island were formed after the eruption of a supervolcano some 75,000 years ago. The island was connected to the surrounding caldera wall by a small isthmus. At 640 square kilometres, Samosir is the largest island within an island, and it also contains two smaller lakes, Lake Sidihoni and Lake Aek Natonang. Across the lake on the east from the island lies Uluan Peninsula, the island is linked to the mainland of Sumatra on its western part by a narrow isthmus connecting the town of Pangururan on Samosir and Tele on mainland Sumatra. Tele consequently offers one of the best views of Lake Toba, Samosir is a popular tourist destination due to its exotic history and the vistas it offers. The tourist resorts are concentrated in the Tuktuk area, the island is the centre of the Batak culture and many of the Toba Batak traditional houses remain on the island. Most of the tourist accommodations are concentrated in the town of Tuktuk. The passenger ferry leaves from Tiga Raja harbor every hour between 8.30 and 19.00, for those running late there is an option to take the passenger boat from Aji bata to Tomok until 8.30 pm. A car ferry leaves the mainland from Ajibata and lands in the town of Tomok. There are also passenger ferries and individual hotels may also have ferries available
Samosir
–
Samosir is in the middle of Lake Toba.
Samosir
–
Samosir Island - Lake Toba1979
Samosir
–
Graves on Samosir Island. 1979
Samosir
–
Sarcophagus in Samosir circa 1916
19.
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
Volcano
–
Cleveland Volcano in the
Aleutian Islands of
Alaska photographed from the
International Space Station, May 2006
Volcano
–
Ash plumes reached a height of 19 kilometres (12 mi) during the climactic
explosive eruption at
Mount Pinatubo, Philippines in 1991.
Volcano
–
A 2007 eruptive column at
Mount Etna producing volcanic ash, pumice and lava bombs
Volcano
–
Ubinas Volcano
20.
1815 eruption of Mount Tambora
–
The 1815 eruption of Mount Tambora was one of the most powerful eruptions in recorded history and is the most recent known VEI-7 event. The eruption column lowered global temperatures, and some believe this led to global cooling. The eruption resulted in a period of significant climate change that led to various cases of extreme weather. Several climate forcings coincided and interacted in a manner that has not been observed since. Although the link between the climate changes and the Tambora event has been established by various scientists, the understanding of the processes involved is incomplete. Mount Tambora experienced several centuries of dormancy before 1815, as the result of the cooling of hydrous magma in a closed magma chamber. Inside the chamber at depths between 1.5 and 4.5 km, the exsolution of a high-pressure fluid magma formed during cooling, overpressure of the chamber of about 4, 000–5,000 bar was generated, and the temperature ranged from 700 to 850 °C. In 1812, the volcano began to rumble and generated a dark cloud, on the morning of 6 April, volcanic ash began to fall in East Java with faint detonation sounds lasting until 10 April. What was first thought to be the sound of firing guns was heard on 10 April on Sumatra more than 2,600 km away, at about 7 pm on 10 April, the eruptions intensified. Three columns of flame rose up and merged, the whole mountain was turned into a flowing mass of liquid fire. Pumice stones of up to 20 cm in diameter started to rain down around 8 pm, pyroclastic flows cascaded down the mountain to the sea on all sides of the peninsula, wiping out the village of Tambora. Loud explosions were heard until the evening,11 April. The ash veil had spread as far as West Java and South Sulawesi, a nitrous odour was noticeable in Batavia and heavy tephra-tinged rain fell, finally receding between 11 and 17 April. The first explosions were heard on this Island in the evening of 5 April, they were noticed in every quarter, the explosion is estimated to have been a VEI-7. An estimated 41 km3 of pyroclastic trachyandesite were ejected, weighing about 10 billion tonnes and this has left a caldera measuring 6–7 km across and 600–700 m deep. The density of ash in Makassar was 636 kg/m³. Before the explosion, Mount Tambora was about 4,300 m high, after the explosion, it measured only 2,851 m. The 1815 Tambora eruption is the largest observed eruption in recorded history, the explosion was heard 2,600 km away, and ash fell at least 1,300 km away
1815 eruption of Mount Tambora
–
False color image of Mount Tambora, taken from the
Space Shuttle Endeavour on 13 May 1992 (for orientation, the top of the image is towards the East).
21.
Piton de la Fournaise
–
Piton de la Fournaise, Peak of the Furnace is a shield volcano on the eastern side of Réunion island in the Indian Ocean. It is currently one of the most active volcanoes in the world, along with Kīlauea in the Hawaiian Islands, Stromboli, Etna, a previous eruption began in August 2006 and ended in January 2007. The volcano erupted again in February 2007, on 21 September 2008, on 9 December 2010, the most recent eruption began on 31 January 2017. The volcano is located within Réunion National Park, a World Heritage site, Piton de la Fournaise is often known locally as le Volcan, it is a major tourist attraction on Réunion island. The top part of the volcano is occupied by the Enclos Fouqué, high cliffs known as remparts form the calderas rim. The caldera is breached to the southeast into the sea and it is unstable and is in the initial stages of failure. It will eventually collapse into the Indian Ocean, whether it will generate a so-called megatsunami is controversial. There is evidence on the flanks and abyssal plain of earlier failures. The lower slopes are known as the Grand Brûlé, most volcanic eruptions are confined to the caldera. Inside the caldera is a 400 meter high lava shield known as Dolomieu, atop the lava shield are Bory Crater and Dolomieu Crater, named for French geologist Déodat Gratet de Dolomieu, which is by far the wider of the two. Many craters and spatter cones can be found inside the caldera, at the beginning of the path that leads to the summit, there lies a noticeable small crater known as Formica Leo, named for its similar shape to the pitfall built by the antlion. Some of the beaches there are of a colour, because of the olivine sand resulting from picrite basalt lavas. Iridium is being ejected through these vents, there were three episodes of caldera collapses 250,000,65,000 and 5,000 years ago. The volcano was formed by the Réunion hotspot, which is believed to have been active for the past 66 million years, there is evidence for explosive eruptions in the past. One explosive eruption about 4,700 years ago may have had a VEI of 5, most eruptions of Piton de la Fournaise are of the Hawaiian style, fluid basaltic lava flowing out with fire fountaining at the vent. Lava flows crossing the Grand Brûlé occasionally reach the sea, with spectacular results, Piton de la Fournaise is one of the most active volcanoes in the world, with more than 150 recorded eruptions since the 17th century. Eruptions within the caldera do not cause much devastation, because the caldera is uninhabited, lava flows are generally confined to the caldera. However, lava flows have been known to cross the N2 highway, in the early 2000s, the highway thus was destroyed once or more times a year, road engineering services then wait for the lava to cool off and build another stretch of road
Piton de la Fournaise
–
Piton de la Fournaise
Piton de la Fournaise
–
The erupting lava met the water of the Indian Ocean during the August 2004 eruption.
Piton de la Fournaise
–
2004 eruption
22.
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
Magma
–
Lava flow on
Hawaii. Lava is the
extrusive equivalent of magma.
23.
Fracture (geology)
–
A fracture is any separation in a geologic formation, such as a joint or a fault that divides the rock into two or more pieces. A fracture will form a deep fissure or crevice in the rock. Fractures are commonly caused by exceeding the rock strength, causing the rock to lose cohesion along its weakest plane. Fractures can provide permeability for fluid movement, such as water or hydrocarbons, highly fractured rocks can make good aquifers or hydrocarbon reservoirs, since they may possess both significant permeability and fracture porosity. Fractures are forms of brittle deformation, there are two types of primary brittle deformation processes. Shear fractures are the first initial breaks resulting from shear forces exceeding the strength in that plane. After those two initial deformations, several types of secondary brittle deformation can be observed, such as frictional sliding or cataclastic flow on reactivated joints or faults. Most often, fracture profiles will look like either a blade, ellipsoid, Fractures in rocks can be formed either due to compression or tension. Fractures due to include thrust faults. Fractures may also be a result from shear or tensile stress, some of the primary mechanisms are discussed below. First, there are three modes of fractures occur, Mode I crack – Opening mode Mode II crack – Sliding mode Mode III crack – Tearing mode For more information on this. This deformation creates propagation of fractures into previously unfractured rock, when the rock is subjected to tensile stress, in the case of a homogenous stress field, the crack will propagate in the direction perpendicular to the least principal stress. Engineers studying elasticity found that the due to a load distant from the region of interest is concentrated around material flaws. A. W. Griffith took this example and applied the concept of stress concentration to the ends of fractures, Griffith asserted that all material have microcracks or flaws where the stress concentration naturally occurs, and that these were the flaws where, under increasing stress, fractures propagate. As a result, these flaws were named Griffith cracks. From this assumption, tensile fracture development may be examined, the first form is in axial stretching. In this case, remote tensile stress is applied, allowing microcracks to open throughout the tensile region. As these cracks open up, the stresses at the crack tips intensify, eventually exceeding the rock strength and this can occur at times of rapid overburden erosion
Fracture (geology)
–
Cracks in rock are a mechanism of
brittle deformation in response to
stress
Fracture (geology)
–
The concentric circles in this
sandstone are "plumose" (plume-like) structures that can form during the formation and propagation of a fracture
24.
Intrusion
–
Intrusive rock is formed when magma crystallizes and solidifies underground to form intrusions, for example plutons, batholiths, dikes, sills, laccoliths, and volcanic necks. Intrusive rock forms within Earths crust from the crystallization of magma, magma slowly pushes up from deep within the earth into any cracks or spaces it can find, sometimes pushing existing country rock out of the way, a process that can take millions of years. As the magma slowly cools into a solid, the different parts of the magma crystallize into rocks, many mountain ranges, such as the Sierra Nevada in California, are formed mostly from large granite intrusions, see Sierra Nevada Batholith. Intrusions are one of the two ways igneous rock can form, the other is extrusive rock, that is, an eruption or similar event. Technically speaking, an intrusion is any formation of igneous rock, rock formed from magma that cools. In contrast, an extrusion consists of rock, rock formed above the surface of the crust. Large bodies of magma that solidify underground before they reach the surface of the crust are called plutons, plutonic rocks form 7% of the Earths current land surface. Coarse-grained intrusive igneous rocks form at depth within the earth are called abyssal while those that form near the surface are called subvolcanic or hypabyssal. The term intrusive suite seems near synonymous, there is, however, a modest difference, An intrusive suite is a group of plutons related in time and space. Intrusions vary widely, from mountain-range-sized batholiths to thin veinlike fracture fillings of aplite or pegmatite, when exposed by erosion, such batholiths may occupy large areas. A well-known example of an intrusion is Devils Tower, another is Shiprock, New Mexico, USA. Be the pluton is large, it may be called a batholith or a stock, Intrusive rocks are characterized by large crystal sizes, and as the individual crystals are visible, the rock is called phaneritic. This is as the magma cools underground, and while cooling may be fast or slow, cooling is slower than on the surface, if it runs parallel to rock layers, it is called a sill. If an intrusion makes rocks above rise to form a dome, as heat dissipation is slow, and as the rock is under pressure, crystals form, and no vitreous rapidly chilled matter is present. The intrusions did not flow while solidifying, hence do not show lines, contained gases could not escape through the thick strata, thus form cavities, which can often be observed. Because their crystals are of the rough equal size, these rocks are said to be equigranular, there is typically no distinction between a first generation of large well-shaped crystals and a fine-grained ground-mass. Earlier crystals originated at a time when most of the rock was still liquid and are more or less perfect, later crystals are less regular in shape because they were compelled to occupy the spaces left between the already-formed crystals. The former case is said to be idiomorphic, the latter is xenomorphic, there are also many other characteristics that serve to distinguish the members of these two groups
Intrusion
–
Devils Tower, an igneous intrusion exposed when the surrounding softer rock eroded away.
Intrusion
–
A dike intrudes into the
country rock,
Baranof Island,
Alaska,
USA.
Intrusion
–
An intrusion (pink
Notch Peak monzonite) inter-fingers (partly as a
dike) with highly metamorphosed black-and-white-striped host rock (
Cambrian carbonate rocks). Near Notch Peak,
House Range,
Utah.
25.
Ring dike
–
A ring dike or ring dyke is an intrusive igneous body that is circular, oval or arcuate in plan and has steep contacts. While the widths of ring dikes differ, they can be up to several thousand meters, the most commonly accepted method of ring dike formation is directly related to collapse calderas. Collapse calderas form due to the emptying of a magma chamber, effusive eruptions that take place on the flanks of the associated volcano and a fissure system that direct magma away from the chamber are both mechanisms that can empty a magma chamber. As pressure in the magma chamber changes, an increase in tensile stresses create tension fractures at the surface of the volcano, the geometry of the top of the magma chamber dictate the location and magnitude of the tension fractures. In addition, it was found that the higher the radius to depth ratio of the magma chamber, once a tension threshold is approached, the roof of the magma chamber collapses in on itself, and is known as calderon subsistence. Tension fractures extend deeper in the profile and shear fractures or dip-slip faults form in a pattern around the caldera and are known as ring faults. Ring faults can be vertical or steeply dipping faults. When they are inward dipping, they are known as normal faults, ring faults then allow magma to rise through the fractures, forming a ring dike. These dikes can form as a result of collapse caldera formation. The magma of a dike is typically composed of acidic or intermediate composition due to the less dense melt that exists at the top of the magma chamber. It has been hypothesized that ring dikes may form when inclined sheets are captured within a fault system. The deflection of the sheets may be caused by the difference in properties between and within the fault zone. Whether or not a ring fault dips inward or outward from the center of subsidence is a highly contentious issue. Ring faults near the surface are subject to erosion and mass wasting, changing the morphology of the caldera walls, about 36 ring dikes have been found in the Ossipee Mountains in New Hampshire. Caldera subsistence appears to be the leading to the formation of some of the ring dikes. The composition ranges from monzonite to quartz syenite, the Loch Bà ring dike, found on the Isle of Mull in Scotland, serves as a classic example of a well formed ring dike. This intrusive body forms an oval and its diameter can be measured at roughly 5.8 km by 8.5 km, the width of the dike varies throughout the profile, with a maximum width of approximately 300 meters. The composition varies from rhyolite to felsite, with phenocrysts of alkali feldspar, batholith Cone sheet Fissure vent Laccolith Billings, Marland P
Ring dike
–
Ring dykes in the
Pilanesberg Game Reserve, South Africa
26.
Ore deposit
–
An ore is a type of rock that contains sufficient minerals with important elements including metals that can be economically extracted from the rock. The ores are extracted from the earth through mining, they are refined to extract the valuable element. The grade or concentration of an ore mineral, or metal, as well as its form of occurrence, will directly affect the costs associated with mining the ore. The cost of extraction must thus be weighed against the value contained in the rock to determine what ore can be processed. Metal ores are generally oxides, sulfides, silicates, or native metals that are not commonly concentrated in the Earths crust, the ores must be processed to extract the metals of interest from the waste rock and from the ore minerals. Ore bodies are formed by a variety of geological processes, the process of ore formation is called ore genesis. An ore deposit is an accumulation of ore and this is distinct from a mineral resource as defined by the mineral resource classification criteria. An ore deposit is one occurrence of a particular ore type, Ore deposits are classified according to various criteria developed via the study of economic geology, or ore genesis. Stratiform arkose-hosted and shale-hosted copper, typified by the Zambian copperbelt and this identifies, early on, whether further investment in estimation and engineering studies is warranted and identifies key risks and areas for further work. This is because the distribution of ores is unequal and dislocated from locations of peak demand. Other, lesser, commodities do not have international clearing houses and benchmark prices and this generally makes determining the price of ores of this nature opaque and difficult. Such metals include lithium, niobium-tantalum, bismuth, antimony and rare earths, most of these commodities are also dominated by one or two major suppliers with >60% of the worlds reserves. The London Metal Exchange aims to add uranium to its list of metals on warrant, the World Bank reports that China was the top importer of ores and metals in 2005 followed by the USA and Japan. Economic geology Mineral resource classification Ore genesis Petrology Froth Flotation Extractive metallurgy DILL, the “chessboard” classification scheme of mineral deposits, Mineralogy and geology from aluminum to zirconium, Earth-Science Reviews, Volume 100, Issue 1-4, June 2010, Pages 1-420
Ore deposit
–
Manganese ore –
psilomelane (size: 6.7 × 5.8 × 5.1 cm)
Ore deposit
–
Iron ore (
Banded iron formation)
Ore deposit
–
Lead ore –
galena and
anglesite (size: 4.8 × 4.0 × 3.0 cm)
Ore deposit
–
Gold ore (size: 7.5 × 6.1 × 4.1 cm)
27.
Northwestern Ontario
–
Northwestern Ontario is a secondary region of Northern Ontario which lies north and west of Lake Superior, and west of Hudson Bay and James Bay. It includes most of subarctic Ontario and its western boundary is the Canadian province of Manitoba, which disputed Ontarios claim to the western part of the region. Ontarios right to Northwestern Ontario was determined by the Judicial Committee of the Privy Council in 1884, for some purposes, Northwestern Ontario and Northeastern Ontario are treated as separate regions, while for other purposes they are grouped together as Northern Ontario. Northwestern Ontario consists of the districts of Kenora, Rainy River and Thunder Bay, major communities in the region include Thunder Bay, Kenora, Dryden, Fort Frances, Sioux Lookout, Greenstone, Red Lake, Marathon, and Atikokan. There are also several dozen First Nations in Northwestern Ontario, Northwestern Ontario is divided between the Eastern Time Zone and the Central Time Zone. Northwestern Ontario is the provinces most sparsely populated region —54 per cent of the entire population lives in the Thunder Bay census metropolitan area alone. Aside from the city of Thunder Bay, Kenora is the other municipality in the entire region with a population of greater than 10,000 people. Northwestern Ontarians tend to lean left politically, mainly due to the history and influence of unions, a growing environmental ethic. At the federal level, Northwestern Ontario is represented by Liberal MPs Bob Nault in the Kenora District, Don Rusnak in Thunder Bay—Rainy River, provincially, NDP Sarah Campbell represents Kenora—Rainy River while Liberals Bill Mauro and Michael Gravelle represent Thunder Bay—Atikokan and Thunder Bay—Superior North respectively. In 2005, some residents of the region expressed dissatisfaction at the level of attention paid to the region by the provincial government, Northern Ontario Northeastern Ontario Gateway to Northwestern Ontario History
Northwestern Ontario
–
Kenora
Northwestern Ontario
–
Northwestern Ontario
Northwestern Ontario
–
Thunder Bay
28.
Explosive eruption
–
An explosive eruption is a volcanic term to describe a violent, explosive type of eruption. Mount St. Helens in 1980 was an example, such eruptions result when sufficient gas has dissolved under pressure within a viscous magma such that expelled lava violently froths into volcanic ash when pressure is suddenly lowered at the vent. Sometimes a lava plug will block the conduit to the summit, Explosive eruptions can send rocks, dust, gas and pyroclastic material up to 20 km into the atmosphere at rate of up to 100,000 tonnes per second, traveling at several hundred meters per second. This cloud will collapse, creating a pyroclastic flow of hot volcanic matter. An explosive eruption always begins with some form of blockage in the crater of a volcano that prevents the release of trapped in highly viscous andesitic or rhyolitic magma. The high viscosity of these forms of magma prevents the release of trapped gases, when this type of magma flows towards the surface pressure builds, eventually causing the blockage to be blasted out in an explosive eruption. The pressure from the magma and gases are released through the weakest point in the cone, however, in the case of the eruption of Mount St. Helens, pressure was released through the side of the volcano, rather than the crater. The size and duration of the column depends on the volume of magma being released, the eruption column of ash is supported by pressure from the gases being released, and as the gases are depleted, pressure falls and the eruption column begins to collapse. When the column collapses in on itself, ash and rock fall back down to the ground and these flows can travel at up to 80 km per hour, and reach temperatures of 200° to 700° Celsius. The high temperatures can cause combustion of any flammable materials in its path, including wood, vegetation, when snow and ice melt as a part of an eruption, large amounts of water mixed in with the flow can create lahars. The risk of lahars is particularly high on volcanoes such as Mount Rainier near Seattle and Tacoma, the eruption of supervolcanoes is the rarest of volcanic eruptions but also the most destructive. The timescale between these eruptions is generally marked by hundreds or thousands of years and this type of eruption generally causes destruction on a continental scale, and can also result in the lowering of temperatures worldwide. Effusive eruption Volcanic explosivity index Recent Developments in Explosive Volcanism
Explosive eruption
–
Mount Saint Helens explosive eruption on July 22, 1980
Explosive eruption
–
An early stage of the July 12, 2009 eruption of
Sarychev volcano, seen from space
29.
Ignimbrite
–
Ignimbrites are made of a very poorly sorted mixture of volcanic ash and pumice lapilli, commonly with scattered lithic fragments. The ash is composed of shards and crystal fragments. Ignimbrites may be loose and unconsolidated, or lithified rock called lapilli-tuff, near the volcanic source, ignimbrites commonly contain thick accumulations of lithic blocks, and distally, many show meter-thick accumulations of rounded cobbles of pumice. Ignimbrites may be white, grey, pink, beige, brown or black depending on their composition, many pale ignimbrites are dacitic or rhyolitic. Darker coloured ignimbrites may be densely welded volcanic glass or, less commonly, there are two main models that have been proposed to explain the deposition of ignimbrites from a pyroclastic density current, the en masse deposition and the progressive aggradation models. The en masse model was proposed by volcanologist Robert Stephen John Sparks in 1976, Sparks attributed the poor sorting in ignimbrites to laminar flows of very high particle concentration. Pyroclastic flows were envisioned as being similar to flows, with a body undergoing laminar flow. The flow would travel as a flow, with an essentially non-deforming mass travelling on a thin shear zone. This would produce a unit with an inversely graded base. There are several problems with the en masse model, since ignimbrite is a deposit, its characteristics cannot completely represent the flow, and the deposit may only record the depositional process. It has been posited that the changes are recording progressive aggradation at the base of the flow from an eruption whose composition changes with time. For this to be so, the base of the flow cannot be turbulent, the instantaneous deposition of an entire body of material is not possible because displacement of the fluid is not possible instantaneously. Any displacement of the fluid would mobilize the upper part of the flow, rheomorphic structures are only observed in high grade ignimbrites. There are two types of flow, post-depositional re-mobilization, and late stage viscous flow. While there is debate in the field of the relative importance of either mechanism. A change from particulate flow to a fluid could cause the rapid en masse cooling in the last few meters. It is also theorized that transformation occurs at a layer at the base of the flow. Another model proposed is that the density current became stationary before the structures form
Ignimbrite
–
Rocks from the
Bishop tuff from California, United States, uncompressed with
pumice on left; compressed with
fiamme on right.
Ignimbrite
–
Rheomorphic flow structures in a welded ignimbrite, Isle of Lipari, Italy
Ignimbrite
–
A block of Ignimbrite
Ignimbrite
–
Light microscope image of a welded ignimbrite, composed of eutaxitic lapilli-tuff as seen in thin section (Long dimension is several mm). The glass shards (mostly brown) sometimes become welded together when the deposit is still hot, and can be deformed by flow and compaction about crystal fragments (clear).
Mount Pinatubo, Philippines
Crater Lake, Oregon, formed around 5,680 BC
Aniakchak-caldera, Alaska
Coatepeque Caldera, El Salvador crater lake
Satellite photo of Lake Taupo
