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Auckland Volcanic Field
The Auckland volcanic field is an area of monogenetic volcanoes covered by much of the metropolitan area of Auckland, New Zealand's largest city, located in the North Island. The approximately 53 volcanoes in the field have produced a diverse array of maars (explosion craters), tuff rings, scoria cones, and lava flows. With the exception of Rangitoto, no volcano has erupted more than once, but the other eruptions lasted for various periods ranging from a few weeks to several years. Rangitoto erupted several times and recently twice; in an eruption that occurred about 600 years ago, followed by a second eruption approximately 50 years later. The field is fuelled entirely by basaltic magma, unlike the explosive subduction-driven volcanism in the central North Island, such as at Mount Ruapehu and Lake Taupō.Ian E.M. Smith and Sharon R. Allen. Auckland volcanic field geology'. Volcanic Hazards Working Group, Civil Defence Scientific Advisory Committee. Retrieved 30 March 2013. Als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ōrākei Basin
Ōrākei Basin is one of the volcanoes in the Auckland volcanic field in the North Island of New Zealand. It has an explosion crater around 700 m wide, with a surrounding tuff ring. The present basin is slightly larger than the original maar crater. Geology After eruption at least 83,000 years ago, it became a freshwater lake that had an overflow stream in the vicinity of present Ōrākei Rd bridge. As sea level rose after the end of the Last Ice Age, the lake, which by then had shallowed to a swamp, was breached by the sea and has been a tidal lagoon ever since. A tidal lagoon, it is popular for watersports. History A railway line (the North Island Main Trunk, branded as the Eastern Line for suburban services) runs through the north side of the basin. The railway runs along a causeway embankment which was constructed in the 1920s and created a barrier between the Ōrākei Basin and the rest of the Waitematā Harbour Waitematā Harbour is the main access by sea to Auc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferdinand Von Hochstetter
Christian Gottlieb Ferdinand Ritter von Hochstetter (30 April 1829 – 18 July 1884) was a German- Austrian geologist. Career Having received his early education at the evangelical seminary at Maulbronn, Ferdinand proceeded to the University of Tübingen and the Tübinger Stift; there, under Friedrich August von Quenstedt, the interest he already felt in geology became permanently fixed, and he obtained his doctor's degree and a travelling scholarship. In 1852 he joined the staff of the Imperial Geological Survey of Austria and was engaged until 1856 in parts of Bohemia, especially in the Bohemian Forest, and in the Fichtel Hills and Karlsbad mountains. His excellent reports established his reputation. Thus he came to be chosen as geologist to the Novara expedition (1857–59), and made numerous valuable observations in the voyage round the world. The Novara arrived in New Zealand on 22 December 1858. Almost immediately he met the German scientist Julius von Haast who had a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dormant 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. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
