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Scoria Macro Digon3
Scoria is a pyroclastic, highly vesicular, dark-colored volcanic rock that was ejected from a volcano as a molten blob and cooled in the air to form discrete grains or clasts.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds. (2005) ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. It is typically dark in color (generally dark brown, black or purplish-red), 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. The holes or vesicles form when gases that were dissolved in the magma come out of solution as it erupts, creating bubbles in the molten rock, some of which are frozen in place as the rock cools and solidifies. Scoria may form as part of a lava flow, typically near its surface, or as fragmental ejecta (lapilli, blocks and bombs), for inst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scoria Macro Digon3
Scoria is a pyroclastic, highly vesicular, dark-colored volcanic rock that was ejected from a volcano as a molten blob and cooled in the air to form discrete grains or clasts.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds. (2005) ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. It is typically dark in color (generally dark brown, black or purplish-red), 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. The holes or vesicles form when gases that were dissolved in the magma come out of solution as it erupts, creating bubbles in the molten rock, some of which are frozen in place as the rock cools and solidifies. Scoria may form as part of a lava flow, typically near its surface, or as fragmental ejecta (lapilli, blocks and bombs), for inst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Glass
Volcanic glass is the amorphous (uncrystallized) product of rapidly cooling magma. Like all types of glass, it is a state of matter intermediate between the closely packed, highly ordered array of a crystal and the highly disordered array of liquid. Volcanic glass may refer to the interstitial material, or matrix, in an aphanitic (fine-grained) volcanic rock, or to any of several types of vitreous igneous rocks. Origin Volcanic glass is formed when magma is rapidly cooled. Magma rapidly cooled to below its normal crystallization temperature becomes a supercooled liquid, and, with further rapid cooling, this becomes an amorphous solid. The change from supercooled liquid to glass occurs at a temperature called the glass transition temperature, which depends on both cooling rate and the amount of water dissolved in the magma. Magma rich in silica and poor in dissolved water is most easily cooled rapidly enough to form volcanic glass. As a result, rhyolite magmas, which are high in s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ahu Tahai
The Tahai Ceremonial Complex is an archaeological site on Rapa Nui (Easter Island) in Chilean Polynesia. Restored in 1974 by American archaeologist William Mulloy, Tahai comprises three principal ''ahu'' from north to south: Ko Te Riku (with restored eyes), Tahai, and Vai Ure. Visible in the distance from Tahai are two restored ''ahu'' at Hanga Kio'e, projects that Mulloy undertook in 1972. Like other Mulloy restoration projects at Ahu Akivi, the ceremonial village of Orongo and Vinapu, the ceremonial center at Tahai now constitutes an integral part of the Rapa Nui National Park, designated by UNESCO as a World Heritage A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for ... site. William Mulloy and Emily Ross Mulloy are buried at Tahai. References * Mulloy, W.T., and S.R. Fischer. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, smaller islands. With an area of , Australia is the largest country by area in Oceania and the world's List of countries and dependencies by area, sixth-largest country. Australia is the oldest, flattest, and driest inhabited continent, with the least fertile soils. It is a Megadiverse countries, megadiverse country, and its size gives it a wide variety of landscapes and climates, with Deserts of Australia, deserts in the centre, tropical Forests of Australia, rainforests in the north-east, and List of mountains in Australia, mountain ranges in the south-east. The ancestors of Aboriginal Australians began arriving from south east Asia approximately Early human migrations#Nearby Oceania, 65,000 years ago, during the Last Glacial Period, last i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Far North Queensland
Far North Queensland (FNQ) is the northernmost part of the Australian state of Queensland. Its largest city is Cairns and it is dominated geographically by Cape York Peninsula, which stretches north to the Torres Strait, and west to the Gulf Country. The waters of Torres Strait include the only international border in the area contiguous with the Australian mainland, between Australia and Papua New Guinea. The region is home to three World Heritage Sites, the Great Barrier Reef, the Wet Tropics of Queensland and Riversleigh, Australia's largest fossil mammal site. Far North Queensland lays claim to over 70 national parks, including Mount Bartle Frere; with a peak of it is the highest peak in both Northern Australia and Queensland. The Far North region is the only region of Australia that is the indigenous country of both Aboriginal Australians and Torres Strait Islanders. Far North Queensland supports a significant agricultural sector, a number of significant mines and is h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Quincan
Mount Quincan is a volcanic mountain near Yungaburra on the Atherton Tableland in Far North Queensland, Australia. The extinct volcano is one of many cinder cones in the Atherton Tableland region. Its crater is approximately 500 m across, with the main cone being to the northwest. Several of the nearby Seven Sisters cinder cones also have their craters to the southeast, which is possibly due to the ash and scoria being blown to the northwest by the prevailing SE winds. Swamp deposits within the crater were dated at 7250 years old, making that the minimum age for Mt Quincan. The scoria deposits also contain abundant mantle xenoliths of peridotite. Quincan, a type of Scoria Scoria is a pyroclastic, highly vesicular, dark-colored volcanic rock that was ejected from a volcano as a molten blob and cooled in the air to form discrete grains or clasts.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds. (2005) ''G ..., is mined from the south west quadrant of the mountain. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island country by area, covering . New Zealand is about east of Australia across the Tasman Sea and south of the islands of New Caledonia, Fiji, and Tonga. The country's varied topography and sharp mountain peaks, including the Southern Alps, owe much to tectonic uplift and volcanic eruptions. New Zealand's capital city is Wellington, and its most populous city is Auckland. The islands of New Zealand were the last large habitable land to be settled by humans. Between about 1280 and 1350, Polynesians began to settle in the islands and then developed a distinctive Māori culture. In 1642, the Dutch explorer Abel Tasman became the first European to sight and record New Zealand. In 1840, representatives of the United Kingdom and Māori chiefs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auckland
Auckland (pronounced ) ( mi, Tāmaki Makaurau) is a large metropolitan city in the North Island of New Zealand. The List of New Zealand urban areas by population, most populous urban area in the country and the List of cities in Oceania by population, fifth largest city in Oceania, Auckland has an urban population of about It is located in the greater Auckland Region—the area governed by Auckland Council—which includes outlying rural areas and the islands of the Hauraki Gulf, and which has a total population of . While European New Zealanders, Europeans continue to make up the plurality of Auckland's population, the city became multicultural and Cosmopolitanism, cosmopolitan in the late-20th century, with Asian New Zealanders, Asians accounting for 31% of the city's population in 2018. Auckland has the fourth largest Foreign born, foreign-born population in the world, with 39% of its residents born overseas. With its large population of Pasifika New Zealanders, the city is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maungarei
Maungarei (officially known as Maungarei / Mount Wellington) is a 135-metre volcanic peak and Tūpuna Maunga (ancestral mountain) located in the Auckland volcanic field of Auckland, New Zealand. It is the youngest onshore volcano of the Auckland volcanic field, having been formed by an eruption around 10,000 years ago. It is the largest of Auckland's scoria cones and has a near-circular base with a flattish rim and three small craters. It is situated in the Mount Wellington suburb of East Auckland. Geology A number of lava flows were created by the mountain's eruption, including one which was six kilometres in length, stretching to the Manukau Harbour at Southdown. Another lava flow blocked the course of a river valley, forming Lake Waiatarua. History The name is short for Te Maungarei ā Pōtaka, the ancient Ngāi Tai ki Tāmaki / Te Waiōhua chief whose domain included the mountain and surrounding areas. Maungarei is also translated as "the watchful mountain" or "t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Cone
Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fragments ejected during the eruption. Types of volcanic cones include stratocones, spatter cones, tuff cones, and cinder cones. Stratocone Stratocones are large cone-shaped volcanoes made up of lava flows, explosively erupted pyroclastic rocks, and igneous intrusives that are typically centered around a cylindrical vent. Unlike shield volcanoes, they are characterized by a steep profile and periodic, often alternating, explosive eruptions and effusive eruptions. Some have collapsed craters called calderas. The central core of a stratocone is commonly dominated by a central core of intrusive rocks that range from around to over several kilometers in diameter. This central core is surrounded by multiple generations of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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