Título del libro: Volcanism And Subduction: The Kamchatka Region
Título del capítulo: Thermal Models Beneath Kamchatka and the Pacific Plate Rejuvenation from a Mantle Plume Impact
VLAD CONSTANTIN MANEA; MARINA MANEA;
Autores externos:
Idioma:
Inglés
Año de publicación:
2013
Palabras clave:
Subduction zones-Russia (Federation)-Kamchatskaia oblast'; Volcanism-Russia (Federation)-Kamchatskaia oblast'
Resumen:
The Northwest Pacific area, comprising the Kamchatka peninsula, is a distinctive area where a series of on going geodynamical processes like: plate rejuvenation from a mantle plume impact, slab detachment, slab edge melting and exotic volcanism, take place. With the help of finite element modeling we infer the thermal structure across Kamchatka in a series of 2D profiles normal to the trench. We chose the location at these profiles based on seismicity, geochemical variation and offshore heat flow measurements. Assuming that the transition from brittle to ductile behavior inside the subducting slab corresponds to the 650°C isotherm, our thermal models predict a good fit with maximum depth of seismicity (~500 km) for southern Kamchatka only if the exothermic olivine-spinel phase transition is introduced. In the central part of Kamchatka, a good fit is obtained if the hot mantle plume, located just beneath Meiji Guyot seamount, thermally rejuvenates the subducting Pacific plate. Further to the north, the seismicity shallows more (200-100 km) and slab rejuvenation alone cannot provide a thermal structure with a good fit with seismically active subducting slab. A good explanation for such shallow seismicity might be the slab detachment due to cessation of subduction just north of Kamchatka-Aleutians junction. The thermal structure beneath the northernmost active volcano in Kamchatka, Scheveluch, which exhibits a strong adakitic signature, shows that slab edge exposure to the hotter asthenosphere creates the favorable conditions for oceanic crust melting at ~70 km depth, just beneath Scheveluch. Our numerical models show that plate rejuvenation from a mantle plume, slab edge exposure to hot upper mantle and probably slab detachment play an essential role in subduction slabs thermal structure, seismicity down-dip extension and geochemical variations of lavas in Kamchatka. © 2007 by the American Geophysical Union. All rights reserved.
Entidades citadas de la UNAM:
ISBN:
9781118666371
Editorial:
American Geophysical Union Nombre de la publicación:
Thermal Models Beneath Kamchatka and the Pacific Plate Rejuvenation from a Mantle Plume Impact
Página inicial:
77
Página final:
89
