1.
One Tree Hill (New Zealand)
–
Maungakiekie / One Tree Hill is a 182-metre volcanic peak in Auckland, New Zealand. It is an important memorial place for both Māori and other New Zealanders, the suburb around the base of the hill is also called One Tree Hill. It is surrounded by the suburbs of Royal Oak to the west, and clockwise, Epsom, Greenlane, Oranga, the summit provides views across the Auckland area, and allows visitors to see both of Aucklands harbours. The hills scoria cones were erupted from three craters – one is intact and two have been breached by lava flows that rafted away part of the side of the scoria cone. Lava flows went in all directions, many towards Onehunga, covering an area of 20 square kilometres, making it the second largest of the Auckland volcanic field, behind Rangitoto Island. The age of eruption is unknown, but it is older than 28,500 years as it has a mantling of volcanic ash erupted at that time from Te Tātua-a-Riukiuta volcano. The Māori name Maungakiekie means mountain of the kiekie vine, Māori also knew it as tōtara that stands alone. The mountain and its surrounds were home to the Te Wai ō Hua tribe from the early 1700s, other Māori tribes in the Auckland area can also trace their ancestry to the mountain. Maungakiekie was the largest and most important Māori pā in pre-European times, the cone and its surroundings are estimated to have been home to a population of up to 5,000. Its position between the Waitemata Harbour to the east and the Manukau Harbour to the west offered a variety of seafood from the two harbours. The volcanic soil on the cone was highly fertile. The hill was relatively easy to defend from raiding parties from other tribes due to its steep sides, the Government under its preemptive rights excluded 115 acres of the hill itself from the sale and this was vested in the Crown. This is now One Tree Hill Domain, in 1853 Brown & Campbell purchased Henrys land surrounding the recently protected One Tree Hill Domain. This land ultimately became Cornwall Park in 1901, in 1964 the government led an initiative to restore the mountain. After two years the initiative was cancelled and the mountain left alone, One Tree Hill Domain is a park, owned by Ngā Mana Whenua o Tāmaki Makaurau Collective and administered by Ngā Mana Whenua o Tāmaki Makaurau Authority. One Tree Hill Domain adjoins Cornwall Parks creating a total of 220 hectares of green space. The hilltop is always accessible by foot but because it became a nightly party stop for boy racers, the area contains two parks, One Tree Hill Domain and Cornwall Park, which are next to each other and thus often perceived as one. One Tree Hill Domain is open to the public and formerly administered by Auckland City Council, all decisions are made by the owners who have delegated minor day-to-day operations to Cornwall Park Trust
2.
Auckland
–
Auckland is a city in the North Island of New Zealand. It is the most populous area in the country. Auckland has a population of 1,495,000, which constitutes 32 percent of New Zealands population, a diverse and multicultural city, Auckland is home to the largest Polynesian population in the world. It has also been called Ākarana, the Māori pronunciation of Auckland, the Auckland urban area ranges to Waiwera in the north, Kumeu in the northwest, and Runciman in the south. It is not contiguous, the section from Waiwera to Whangaparāoa Peninsula is separate from its nearest neighbouring suburb of Long Bay, the surrounding hills are covered in rainforest and the landscape is dotted with dozens of dormant volcanic cones. The central part of the area occupies a narrow isthmus between the Manukau Harbour on the Tasman Sea and the Waitemata Harbour on the Pacific Ocean. It is one of the few cities in the world to have harbours on two major bodies of water. The isthmus on which Auckland resides was first settled around 1350 and was valued for its rich, Māori population in the area is estimated to have peaked at 20,000 before the arrival of Europeans. After a British colony was established in 1840, the new Governor of New Zealand, William Hobson and he named the area Auckland for George Eden, Earl of Auckland, British First Lord of the Admiralty. It was replaced as the capital in 1865, but immigration to the new city stayed strong, today, Aucklands Central Business District is the major financial centre of New Zealand. Auckland is classified as a Beta World City because of its importance in finance, commerce, media, entertainment, arts, education and tourism. Aucklands landmarks such as the Auckland Art Gallery Toi o Tāmaki, the Harbour Bridge, the Sky Tower, the isthmus was settled by Māori around 1350, and was valued for its rich and fertile land. Many pā were created, mainly on the volcanic peaks, Māori population in the area is estimated to have been about 20,000 people before the arrival of Europeans. As a result, the region had relatively low numbers of Māori when European settlement of New Zealand began, there is, however, nothing to suggest that this was the result of a deliberate European policy. Auckland was officially declared New Zealands capital in 1841 and the transfer of the administration from Russell in the Bay of Islands was completed in 1842. However, even in 1840 Port Nicholson was seen as a choice for an administrative capital because of its proximity to the South Island. After losing its status as capital, Auckland remained the city of the Auckland Province until the provincial system was abolished in 1876. Each of the four settlements had about 800 settlers, the men being fully armed in case of emergency but spent nearly all their time breaking in the land and establishing roads
3.
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
4.
Shield volcano
–
A shield volcano is a type of volcano usually built almost entirely of fluid lava flows. They are named for their low profile, resembling a warriors shield lying on the ground and this is caused by the highly fluid lava they erupt, which travels farther than lava erupted from stratovolcanoes. This results in the accumulation of broad sheets of lava. The shape of shield volcanoes is due to the low viscosity of their mafic lava, Shield volcanoes are built by effusive eruptions, which flow out in all directions to create a shield like that of a warrior. Shield volcano itself is taken from the German term Schildvulkan, examples of pyroclastic shields include Billy Mitchell volcano in Papua New Guinea and the Purico Complex in Chile, an example of a felsic shield is the Big Obsidian Flow in Oregon. Active shield volcanoes experience near-continuous eruptive activity over long periods of time. Mount Everest, by comparison, is 8,848 m in height, the research has not yet been confirmed. Shield volcanoes feature a slope that gradually steepens with elevation before eventually flattening near the summit. In height they are typically about one twentieth their width, although the general form of a typical shield volcano varies little worldwide regional differences exist in their size and morphological characteristics. 4° and an average volume of 1.7 km3. Rift zones are a prevalent feature on shield volcanoes that is rare on other volcanic types, the large, decentralized shape of Hawaiian volcanoes as compared to their smaller, symmetrical Icelandic cousins can be attributed to rift eruptions. Fissure venting is common in Hawaiʻi, most Hawaiian eruptions begin with a wall of fire along a major fissure line before centralizing to a small number of points. These eruptions, the calmest of volcanic events, are characterized by the emission of highly fluid basaltic lavas with low gaseous content. These lavas travel a far greater distance than those of other types before solidifying, forming extremely wide. Low volumes of such lavas layered over long periods of time are what slowly constructs the characteristically low, central-vent eruptions, meanwhile, often take the form of large lava fountains, which can reach heights of hundreds of meters or more. If eruptive rates are enough, they may even form splatter-fed lava flows. Hawaiian eruptions are often extremely long lived, Puʻu ʻŌʻō, a cone of Kilauea, has been erupting continuously since 1983. These lava flows can be anywhere between 2 and 20 m thick, pāhoehoe flows, in contrast, move in more conventional sheets, or by the advancement of lava toes in snaking lava columns. Increasing viscosity on the part of the lava or shear stress on the part of local topography can morph a pāhoehoe flow into an aa one, although most shield volcanoes are by volume almost entirely Hawaiian and basaltic in origin, they are rarely exclusively so
5.
Hectare
–
The hectare is an SI accepted metric system unit of area equal to 100 ares and primarily used in the measurement of land as a metric replacement for the imperial acre. An acre is about 0.405 hectare and one hectare contains about 2.47 acres, in 1795, when the metric system was introduced, the are was defined as 100 square metres and the hectare was thus 100 ares or 1⁄100 km2. When the metric system was further rationalised in 1960, resulting in the International System of Units, the are was not included as a recognised unit. The hectare, however, remains as a non-SI unit accepted for use with the SI units, the metric system of measurement was first given a legal basis in 1795 by the French Revolutionary government. At the first meeting of the CGPM in 1889 when a new standard metre, manufactured by Johnson Matthey & Co of London was adopted, in 1960, when the metric system was updated as the International System of Units, the are did not receive international recognition. The units that were catalogued replicated the recommendations of the CGPM, many farmers, especially older ones, still use the acre for everyday calculations, and convert to hectares only for official paperwork. Farm fields can have long histories which are resistant to change, with names such as the six acre field stretching back hundreds of years. The names centiare, deciare, decare and hectare are derived by adding the standard metric prefixes to the base unit of area. The centiare is a synonym for one square metre, the deciare is ten square metres. The are is a unit of area, equal to 100 square metres and it was defined by older forms of the metric system, but is now outside of the modern International System of Units. It is commonly used to measure real estate, in particular in Indonesia, India, and in French-, Portuguese-, Slovakian-, Serbian-, Czech-, Polish-, Dutch-, in Russia and other former Soviet Union states, the are is called sotka. It is used to describe the size of suburban dacha or allotment garden plots or small city parks where the hectare would be too large, the decare is derived from deka, the prefix for 10 and are, and is equal to 10 ares or 1000 square metres. It is used in Norway and in the former Ottoman areas of the Middle East, the hectare, although not strictly a unit of SI, is the only named unit of area that is accepted for use within the SI. The United Kingdom, United States, Burma, and to some extent Canada instead use the acre, others, such as South Africa, published conversion factors which were to be used particularly when preparing consolidation diagrams by compilation. In many countries, metrication redefined or clarified existing measures in terms of metric units, non-SI units accepted for use with the International System of Units
6.
Auckland volcanic field
–
The Auckland volcanic field is an area of monogenetic volcanoes covered by much of the metropolitan area of Auckland, New Zealands largest city, located in the North Island. The fields 53 volcanoes have produced an array of maars, tuff rings, scoria cones. Each volcano has erupted for just one period, lasting for weeks to years, except for Rangitoto Island. The field is fuelled entirely by basaltic magma, unlike the explosive subduction-driven volcanism in the central North Island, such as at Mount Ruapehu, the field is currently dormant, but has the potential to become active again in the future. The field ranges from Lake Pupuke and Rangitoto Island in the north to Matukutururu in the south, the first vent erupted at Onepoto Volcano 248,000 ±28,000 years ago. The most recent eruption was of Rangitoto, a shield volcano just east of the city. The eruptions have tended to become bigger over time, with Rangitoto making up almost 60% of the entire volume of erupted material. All of the volcanoes are small, most being less than 150 meters in height. Lake Pupuke, on the North Shore near Takapuna, is an explosion crater. A few similar craters such as Orakei Basin are open to the sea, the field has produced voluminous lava flows that cover much of the Auckland isthmus. One of the longest runs from Mt Saint John northward, almost crossing the Waitemata Harbour to form Meola Reef, more than 50 lava tubes and other lava caves have been discovered, including the 290 metre long Wiri Lava Cave. The second longest individual cave in the Auckland field, some 270 metres in length, is the Cave of a Thousand Press-ups to the east of One Tree Hill. Two impressive depressions caused by lava cave collapses are the Puka Street Grotto, all the volcanoes probably erupted on land except for Rangitoto, which erupted during the current interglacial period. Many of the cones were occupied by substantial Māori pa before European settlement. Many of the cones have been levelled or strongly altered – in small part due to the historical Māori use, however several of the remaining volcanoes are now preserved as landmarks and parks. While often ignored until the late 20th century, it has amongst other things minimised severe changes to Mount Roskill proposed by Transit New Zealand for the Southwestern Motorway. In March 2007, New Zealand submitted the volcanic field, with several specifically named features, at that time, only 2% of more than 800 World Heritage Sites worldwide were in this mixed category. Since the field is not extinct, new volcanic events may occur at any time and these effects might continue for several months and cause substantial destruction and disruption
7.
Clinker brick
–
Clinker bricks are partially vitrified bricks used in the construction of buildings. Clinkers are burnt under temperatures so high that the pores of the property are closed by the beginning sinter process and are often mis-shapen. Thus they are denser and therefore heavier and more irregular than regular bricks. Clinkers hardly take up water and are durable, but have higher thermal conductivity than the more porous conventional red bricks. The name comes from the sound they make when banged together, in early brick firing kilns called brick clamps, the surface of the bricks that were too close to the fire changed into the volcanic textures and darker/purplish colors. Modern brick-making techniques can recreate the appearance of these bricks and produce a consistent product. In the United States, clinker bricks were made famous by the Pasadena, California architecture firm Greene and Greene who used them in walls, foundations, Clinker is sometimes spelled klinker which is the original Dutch/Low German word. The onomatopoeic verb klinken means to sound, i. e. a klinker is a sounder and these brick stones produce a specifically bright sound when hit with or against something, for instance each other. Clinker bricks are also known as hard Dutch paving bricks, in 18th century New York, the Dutch interspersed dark clinkers with regular bricks. Some used clinkers to spell out their family initials on brick dwellings, clinkers consist of bits and ends, field-late and white-burning or red-burning clays. Through different mixtures of the raw ingredients, many varied colour nuances can be achieved, for the production of masonry units the source materials—clay and water—are mixed and formed industrially in a string extrusion process. For special purposes, for example the restoration of listed buildings, during the drying process, the water concentration decreases to approximately 3%. Then clinkers are fired at temperatures between 1100 °C and 1300 °C in a kiln, in contrast to the 800 °C to 1200 °C temperature range seen with normal bricks. Because of their low porosity, clinker bricks are inferior thermal insulators, canal clinkers are named according to the German Institute for Standardization’s DIN4051. Clinkers are frost resisting and, thus are suited particularly for facades, the formats of the clinker stones are named according to the German Institute for Standardization’s DIN1053. Base for the different formats is the format with length 240 millimetres, width 115 millimetres. For facade layouts architects also order clinkers produced in special dimensions, for use with facades, it is possible to cope varied shaped elements. Sculptor Ernst Barlach also worked with clinkers which then were produced according to his drafts, Clinker bricks take on a special colouring, often greenish tones, if burnt with peat
8.
Scoria
–
Scoria is a highly vesicular, dark colored volcanic rock that may or may not contain crystals. It is typically dark in color, and basaltic or andesitic in composition, Scoria is relatively low in density as a result of its numerous macroscopic ellipsoidal vesicles, but in contrast to pumice, all scoria has a specific gravity greater than 1, and sinks in water. Scoria may form as part of a flow, typically near its surface, or as fragmental ejecta. Most scoria is composed of fragments, and may contain phenocrysts. The word scoria comes from the Greek σκωρία, skōria, rust, an old name for scoria is cinder. Scoria differs from pumice, another vesicular volcanic rock, in having larger vesicles and thicker vesicle walls, the difference is probably the result of lower magma viscosity, allowing rapid volatile diffusion, bubble growth, coalescence, and bursting. As rising magma encounters lower pressures, dissolved gases are able to exsolve, some of the vesicles are trapped when the magma chills and solidifies. Vesicles are usually small, spheroidal and do not impinge upon one another, volcanic cones of scoria can be left behind after eruptions, usually forming mountains with a crater at the summit. An example is Maungarei in New Zealand, which like Te Tatua-a-Riukiuta in the south of the city has been extensively quarried. Quincan, a form of Scoria, is quarried at Mount Quincan in Far North Queensland. Scoria has several characteristics that influence how it is used. It is somewhat porous, has high surface area and strength for its weight, Scoria is often used in landscaping and drainage works. It is also used in gas barbecue grills. Scoria can be used for high-temperature insulation, Scoria is used on oil well sites to limit mud issues with heavy truck traffic. It is also used as a traction aid on ice- and snow-covered roads, cinder Tuff Pumice Volcanoes List of rock types Rock
9.
Lava tube
–
A lava tube is a natural conduit formed by flowing lava which moves beneath the hardened surface of a lava flow. Tubes can be actively draining lava from a volcano during an eruption, or can be extinct, meaning the flow has ceased. Lava tubes are a type of cave formed when an active low-viscosity lava flow develops a continuous and hard crust. Tubes form in one of two ways, by the crusting over of lava channels, and from pāhoehoe flows where the lava is moving under the surface, Lava usually leaves the point of eruption in channels. These channels tend to very hot as their surroundings cool. This means they slowly develop walls around them as the lava cools and/or as the channel melts its way deeper. These channels can get enough to crust over, forming an insulating tube that keeps the lava molten. These types of lava tubes tend to be closer to the eruption point. Farther away from the point, lava can flow in an unchanneled, fanlike manner as it leaves its source. Called pāhoehoe flows, these areas of surface-moving lava cool, forming either a smooth or rough, the lava continues to flow this way until it begins to block its source. At this point, the lava is still hot enough to break out at a point. Lava flows from the source to this breakout point as the surrounding lava of the pāhoehoe flow cools. This forms a channel that becomes a lava tube. A broad lava-flow field often consists of a lava tube. When the supply of lava stops at the end of an eruption or lava is diverted elsewhere, lava in the system drains downslope. Lava tubes generally have pāhoehoe floors, although this may often be covered in breakdown from the ceiling. A variety of speleothems may be found in lava tubes including a variety of stalactite forms generally known as lavacicles, lavacicles are the most common of lava tube speleothems. Drip stalagmites may form under tubular lava stalactites, and the latter may grade into a known as a tubular lava helictite
10.
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
11.
Pterostylis
–
Pterostylis metcalfei.001. jpg Pterostylis is a genus of about 120 species of plants in the orchid family, Orchidaceae. Commonly called greenhood orchids, they are terrestrial, deciduous, perennial, tuberous, herbs found in Australia, New Zealand, New Guinea, New Caledonia and one Indonesian island. The flowers are green, sometimes with brown, reddish or white stripes and are distinguished from other orchids by their unusual flower structures. The galea curves forward, covers the parts of the flower, is important in the pollination process and is about as long as the lateral sepals. The dorsal sepal is translucent white with green, reddish or brown stripes, the two lateral sepals are joined at their base, form the front of the flower and usually protrude to form points or ears which extend above or to the side of the galea. The third petal forms the highly modified labellum, as in other orchids, the sexual parts of the flower form part of the column and in all greenhoods, this structure has a pair of mostly translucent wings and is also important in pollination. The tuber of a greenhood is usually more or less spherical in shape, a new one is produced early in the life of the parent tuber at the same time as a new shoot is produced and continues to grow, reaching maturity at the end of the growing season. In some species, a number of daughter tubers grow. The leaves are attached in a rosette to the base of the peduncle or stalk of the plant by a short petiole, or further up it. There may be one or several flowers on the peduncle, most greenhoods are pollinated by insects, nearly always by tiny flies from the family Mycetophilidae or by mosquitoes. The insect approaches the flower from downwind, as if attracted by a scent, the features of an actively-moving labellum, along with the galea, are unique to these orchids. The fruit of a greenhood is a dehiscent capsule containing up to 500 tiny seeds and is oblong to elliptic in shape with three ridges, other parts of the flower wither soon after pollination and the dry remains are attached to the end of the capsule. The first observation of Pterostylis by European botanists was probably by Joseph Banks when HMS Endeavour visited Botany Bay in 1770, the first formal description of a greenhood was by Jacques Labillardière who collected a specimen from Bruny Island and gave it the name Disperis alata. After several name changes, Disperis alata is now known as Pterostylis alata, the genus Pterostylis was first raised by Robert Brown who formally described 19 species but did not nominate a type species. The species he described were collected from the east coast of the mainland and from Tasmania, about 120 species have now been described and about 100 of them are endemic to Australia. In 2001 the genus Pterostylis was split such that two new genera, Plumatichilos and Oligochaetochilus, were established based on morphological characters and these divisions effectively separated species with a thread-like, feathery labellum, and those with downward-curved lateral sepals from the remaining Pterostylis species. These changes were not adopted widely by Australian herbaria as the data appeared to support a monophyletic group, the genus name is derived from the Ancient Greek words pteron meaning feather or wing and stylos meaning pillar or post referring to the wings on the column. Pterostylis closest relative is Achlydosa, restricted to New Caledonia and sole other genus of subtribe Pterostylidinae, in Australia they are found in all states and Lord Howe Island, but not in the Northern Territory
