TY - JOUR

T1 - Migration of fluids and melts in subduction zones and general aspects of thermophysical modeling in geology

AU - Dobretsov, N. L.

AU - Simonov, V. A.

AU - Koulakov, I. Yu

AU - Kotlyarov, A. V.

PY - 2017/5/1

Y1 - 2017/5/1

N2 - Modeling of fluid-magmatic systems in a suprasubduction mantle wedge is considered for the case of Kamchatka with reference to data on peridotites from other known subduction and oceanic rock complexes. This modeling has to take account of magma storage in several intermediate reservoirs at different depths, up to six such reservoirs, as in the case of Avacha Volcano. Comparison of available data on melt inclusions in spinels indicates crystallization of the Avacha peridotites in magmatic systems progressively decreasing in temperature (> 1200 °C → 1100 °C → 900 °C) and pressure (from 13.8 to 4.5 kbar) in intermediate reservoirs at depths of 30-40 and 15-20 km. The Avacha harzburgites do not belong to primary oceanic mantle as they lack both signatures of high-temperature plastic flow and effects of mantle melts known for sheared mantle peridotites from ophiolite suites. The VP/VS ratio estimated from jointly analyzed P- and S-wave velocities (vP and vs, respectively), an important indicator for seismic tomographic reconstructions of subduction zones, allows discriminating between regions saturated mainly with liquid (melts) and gas phases beneath volcanoes. Only specially tested tomographic data can provide reliable reference for modeling of mantle wedge processes.

AB - Modeling of fluid-magmatic systems in a suprasubduction mantle wedge is considered for the case of Kamchatka with reference to data on peridotites from other known subduction and oceanic rock complexes. This modeling has to take account of magma storage in several intermediate reservoirs at different depths, up to six such reservoirs, as in the case of Avacha Volcano. Comparison of available data on melt inclusions in spinels indicates crystallization of the Avacha peridotites in magmatic systems progressively decreasing in temperature (> 1200 °C → 1100 °C → 900 °C) and pressure (from 13.8 to 4.5 kbar) in intermediate reservoirs at depths of 30-40 and 15-20 km. The Avacha harzburgites do not belong to primary oceanic mantle as they lack both signatures of high-temperature plastic flow and effects of mantle melts known for sheared mantle peridotites from ophiolite suites. The VP/VS ratio estimated from jointly analyzed P- and S-wave velocities (vP and vs, respectively), an important indicator for seismic tomographic reconstructions of subduction zones, allows discriminating between regions saturated mainly with liquid (melts) and gas phases beneath volcanoes. Only specially tested tomographic data can provide reliable reference for modeling of mantle wedge processes.

KW - Avacha Volcano

KW - fluid

KW - Kamchatka

KW - magma reservoir

KW - mantle wedge

KW - melt

KW - melt inclusion

KW - peridotite

KW - seismic tomography

KW - subduction zone

KW - KAMCHATKA

KW - FRACTIONATING BASALTIC MAGMA

KW - PERIDOTITE XENOLITHS

KW - MANTLE WEDGE BENEATH

KW - AVACHA VOLCANO

KW - KLYUCHEVSKOY GROUP

KW - ULTRAMAFIC ROCK

KW - ARC

KW - SEISMIC TOMOGRAPHY

KW - METASOMATISM

UR - http://www.scopus.com/inward/record.url?scp=85019257785&partnerID=8YFLogxK

U2 - 10.1016/j.rgg.2016.09.028

DO - 10.1016/j.rgg.2016.09.028

M3 - Article

AN - SCOPUS:85019257785

VL - 58

SP - 571

EP - 585

JO - Russian Geology and Geophysics

JF - Russian Geology and Geophysics

SN - 1068-7971

IS - 5

ER -