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Rotoiti Caldera
The Rotoiti Caldera is a postulated, mainly infilled sub caldera of the Ōkataina Caldera based upon gravitational and magnetic evidence. While bathymetry of Lake Rotoiti is consistent with volcanic vents being present, they could be in an area of collapse subsidence outside the north western margins of the Rotoiti Caldera itself. It erupted of magma that is used in the recent stratigraphy of much of the northern North Island. It was formed in the larger paired eruption with the lesser Earthquake Flat vents linked by tectonic interaction across the length of the Ōkataina Caldera.Houghton B F, Wilson C J N, McWilliams M O, Lanphere M A, Weaver S D, Briggs R M, Pringle M S, 1995Chronology and dynamics of a large silicic magmatic system: Central Taupo Volcano Zone, New Zealand Geology, 23: 13-16. The series of eruptions was about 50,000 years ago, with the resulting widespread Rotoiti ignimbrite and several layers of Rotoiti/Rotoehu tephra/ brecca/ash giving challenges in consi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ōkataina Caldera
Ōkataina Caldera (Ōkataina Volcanic Centre, also spelled Okataina) is a massive, recently active volcanic caldera and its associated volcanoes located in Taupō Volcanic Zone of New Zealand's North Island. It is just east of the smaller Rotorua Caldera and southwest of the much smaller Rotomā Embayment which is usually regarded as an associated volcano. It is best known for its high rates of explosive rhyolitic volcanism although its last eruption was basaltic. Confusingly the postulated Haroharo Caldera contained within it, has sometimes been described in almost interchangeable terms with the Ōkataina Caldera or volcanic complex or centre and by other authors as a separate complex. Since 2010 other terms such as the Haroharo vent alignment, Utu Caldera, Matahina Caldera, Rotoiti Caldera and a postulated Kawerau Caldera have replaced this classification. Geography The caldera covers an area of about , stretching from Lake Rotoehu in the north to Lake Rotomahana in the south. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Quaternary Volcanic Eruptions
This article is a list of volcanic eruptions of approximately magnitude 6 or more on the Volcanic Explosivity Index (VEI) or equivalent sulfur dioxide emission during the Holocene, and Pleistocene eruptions of the Decade Volcanoes (Avachinsky-Koryaksky, Kamchatka; Colima, Trans-Mexican Volcanic Belt; Mount Etna, Sicily; Galeras, Andes, Northern Volcanic Zone; Mauna Loa, Hawaii; Mount Merapi, Central Java; Mount Nyiragongo, East African Rift; Mount Rainier, Washington; Sakurajima, Kagoshima Prefecture; Santamaria/ Santiaguito, Central America Volcanic Arc; Santorini, Cyclades; Taal Volcano, Luzon Volcanic Arc; Teide, Canary Islands; Ulawun, New Britain; Mount Unzen, Nagasaki Prefecture; Mount Vesuvius, Naples); Campania, Italy; South Aegean Volcanic Arc; Laguna de Bay, Luzon Volcanic Arc; Mount Pinatubo, Luzon Volcanic Arc; Toba, Sunda Arc; Mount Meager massif, Garibaldi Volcanic Belt; Yellowstone hotspot, Wyoming; and Taupō Volcanic Zone, greater than VEI 4. The eruptions in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene Calderas
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek grc, label=none, πλεῖστος, pleīstos, most and grc, label=none, καινός, kainós (latinized as ), 'new'. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by the Isthmus of Panama, causing Great American Interchang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calderas Of New Zealand
A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is gone. The ground surface then collapses into the emptied or partially emptied magma chamber, leaving a large depression at the surface (from one to dozens of kilometers in diameter). Although sometimes described as a crater, the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Compared to the thousands of volcanic eruptions that occur each century, the formation of a caldera is a rare event, occurring only a few times per century. Only seven caldera-forming collapses are known to have occurred between 1911 and 2016. More recently, a caldera collapse occurred at Kīlauea, Hawaii in 2018. Etymology The term ''caldera'' comes from Spanish ', and Latin ', meaning "coo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puhipuhi Embayment
The Puhipuhi Embayment (also Puhipuhi Basin) is a volcanic feature in Taupo Volcanic Zone of New Zealand associated with the collapse of the Ōkataina Caldera wall to its west. Its latest significant volcanic eruption was about 31,500 years ago and this dating required a reassessment of recent activity at the Eastern extension of the Tarawera vent alignment. Geography The Puhipuhi Embayment extends from the eastern margin of Mount Tarawera towards Kawerau including land mostly devoted to the Tarawera Forest portion of the Kaingaroa Forest. The basin is a dissected plateau at about above sea level. The Tarawera River cuts through the north of the basin and is its drainage. Geology Both the Pupipuhi Embayment and the Tarawera Volcanic Complex are part of the Ōkataina Volcanic Centre. There is a long eruptive history with the likelihood that some of the 13 Mangaone Subgroup eruptions were from vents in the embayment and the only dacite eruptives from this centre occur in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brecca
Breca (sometimes spelled Breoca or Brecca) was a Bronding who, according to the Anglo-Saxon poem ''Beowulf'', was Beowulf's childhood friend. Breca defeated Beowulf in what, by consensus, is described as a ''swimming'' match. While dining, Unferth alludes to the story of their contest as a reproach to Beowulf's impulsiveness and foolhardiness, and Beowulf then relates it in detail, explaining how he needed to stop and defeat multiple sea monsters (''nicors'') during the match, so, although he arrived at the goal after Breca, his was the more worthy journey. In line 522 of Beowulf, Breca is identified as ''lond Brondinga'' (“of the Brondings’ land"). Breca is also mentioned in Widsith, an Anglo-Saxon poem (also known, usually by the translations of Benjamin Thorpe, as The Skôp, or The Gleema's Tale, or The Skald's Tale) known only from a 10th-century copy, as the ruler (in some unspecified previous century) of the Brondings (line 25 of Widsith): ::'' Cassere weold Creacum, ond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tephra
Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they remain as tephra unless hot enough to fuse into pyroclastic rock or tuff. Tephrochronology is a geochronological technique that uses discrete layers of tephra—volcanic ash from a single eruption—to create a chronological framework in which paleoenvironmental or archaeological records can be placed. When a volcano explodes, it releases a variety of tephra including ash, cinders, and blocks. These layers settle on the land and, over time, sedimentation occurs incorporating these tephra layers into the geologic record. Often, when a volcano explodes, biological organisms are killed and their remains are buried within the tephra layer. These fossils are later dated by scientists to determine the age of the fossil and its place within the geolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ignimbrite
Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrounding atmosphere. New Zealand geologist Patrick Marshall (1869-1950) coined the term ''ignimbrite'' from the Latin ''igni-'' [fire] and ''imbri-'' [rain]. Ignimbrites are made of a very poorly sorted mixture of volcanic ash (or tuff when Lithification, lithified) and pumice lapilli, commonly with scattered lithic fragments. The ash is composed of glass shards and crystal fragments. Ignimbrites may be loose and unconsolidated, or lithified (solidified) rock called lapilli-tuff. Near the volcanic source, ignimbrites often 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 and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratigraphy
Stratigraphy is a branch of geology concerned with the study of rock (geology), rock layers (Stratum, strata) and layering (stratification). It is primarily used in the study of sedimentary rock, sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostratigraphy (lithologic stratigraphy), biostratigraphy (biologic stratigraphy), and chronostratigraphy (stratigraphy by age). Historical development Catholic priest Nicholas Steno established the theoretical basis for stratigraphy when he introduced the law of superposition, the principle of original horizontality and the principle of lateral continuity in a 1669 work on the fossilization of organic remains in layers of sediment. The first practical large-scale application of stratigraphy was by William Smith (geologist), William Smith in the 1790s and early 19th century. Known as the "Father of English geology", Smith recognized the significance of Stratum, strata or rock layering and the importance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haroharo Caldera
The Haroharo Caldera (Haroharo volcanic complex) is a postulated volcanic feature in Taupō Volcanic Zone of the North Island, New Zealand within the larger and older Ōkataina Caldera. Since 2010 further studies have tended to use the terms Haroharo vent alignment, Utu Caldera, Matahina Caldera, Rotoiti Caldera and a postulated Kawerau Caldera to the features assigned to it. However the name is used in the peer reviewed literature to summarise these features. Geography In the north the Haroharo Caldera extended from the eastern half of Lake Rotoiti to the western border of Lake Rotoma. Its southern extent was defined by the Tarawera volcano. A recent analysis is consistent with the south western structural boundary being in the eastern portions of Lake Tarawera. Geology The Haroharo Caldera is within the older and larger Ōkataina Caldera and its boundaries in geological terms are related mainly to the Matahina and Rotoiti sub-calderas which were formed in single eru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
