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Tolbachick – ​a unique geochemical phenomenon

... potassium content of its eruptive rocks: its basalts contain up to 4 percent of potassium oxide (К 2 О). Such values are not only maximal for the Kamchatka peninsula – ​they are among the highest of all island arc volcanoes formed as the result of subductions (the eruptive rocks of the South American Cordilleras show similar values) It is known that high potassium contents are typical for plume eruption lavas. Without exceptions, all plume rocks, from alkaline to normal basalts, are saturated ...

Modified: 29.12.2018
Pacific Ring of Fire , volcanoes of Kamchatka , klyuchevskoy volcano group , Tolbachik , eruption , tectonics , subduction , seismic tomography , tomographic algorithms , geochemistry
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Tolbachik Eruption – another message from the Land of Volcanoes

... basalt lava. In general, all volcanoes can be divided into two types. Volcanoes of the first time are connected with plumes, and their activity pours the mantle matter onto the surface of Earth. Volcanoes of the second dype are formed in the so called subduction zones, in a process where one tectonic plate submerges beneath another. These subduction areas are characterized by a number of complex chemical, mechanical and thermal processes. This results in massive volumes of water, fluids and molten ...

Modified: 29.12.2018
Pacific Ring of Fire , volcanoes of Kamchatka , klyuchevskoy volcano group , Tolbachik , eruption , tectonics , subduction , seismic tomography , tomographic algorithms , geochemistry
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A Town of Passionarians

Almost a century ago, in the 1920-30s, a special commission of the USSR Academy of Sciences on the organization of regional affiliates denied the request of local governments in Siberia and the Far East of the country to create local affiliate divisions. The stated reason was that it was impossible “to deploy Academicians to the specified cities without the destruction of the Academy of Sciences as such, and selecting new Academicians, forcing them to live and work in a specified city, is impossible...

Modified: 26.10.2017
SB RAS , Novosibirsk Akademgorodok , mantle plumes , subduction , kimberlites , diamonds , oil , gas
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Major Supereruptions in the Earth’s History Were Caused by Deep Water Migration

... the Indian Ocean plate. This zone, which clearly stands out on the map of the seabed, separates two parts of the plate with different ages and is a weakened part of the lithosphere, which facilitates the penetration of seawater to the crust. In the subduction zone, the oceanic Indian plate sinks into the mantle beneath Sumatra and pulls there the water-saturated IFZ. At a depth of about 150 km, directly beneath the Toba Caldera, this water is ejected from the subducting lithospheric plate. Then,...

Modified: 02.09.2016
supervolcanoes , Toba , Sumatra , Indonesia , seismic model , tectonics , subduction , volcanism , caldera , crust structure , magma chambers , supereruptions
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Major Supereruptions in the Earth's History Were Caused by Deep Water Migration

... the Indian Ocean plate. This zone, which clearly stands out on the map of the seabed, separates two parts of the plate with different ages and is a weakened part of the lithosphere, which facilitates the penetration of seawater to the crust. In the subduction zone, the oceanic Indian plate sinks into the mantle beneath Sumatra and pulls there the water-saturated IFZ. At a depth of about 150 km, directly beneath the Toba Caldera, this water is ejected from the subducting lithospheric plate. Then,...

Modified: 08.08.2016
supervolcanoes , Toba , Sumatra , Indonesia , seismic model , tectonics , subduction , volcanism , caldera , crust structure , magma chambers , supereruptions
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Up the Evolutionary Scale. Evolution of the Earth, the Geographical Envelope, Climate, and the Biosphere

... the first maximum of mantle rock ages. Probably, the bilayered convection in the upper and lower mantle, if it existed before the event, was preserved, but it was disturbed by large jets of ascending superplumes and large drops of melting crust from subduction zones, which submerged to the core. According to geochemical evidence, the magma reservoirs of the lower and upper mantle differentiated again by 2.0—1.8 Ga BP. In the Paleoproterozoic, 2.6—2.8 Ga BP, the bulk of the continental crust ...

Modified: 19.04.2013
accretion , Earth evolution , geologic cycles , convection in mantle , subduction , supercontinents , dating by radioactivity
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