Portnyagin Maxim, Hoernle Kaj, Plechov Pavel Yu., Mironov Nikita, Khubunaya Sergey Constraints on mantle melting and composition and nature of slab components in volcanic arcs from volatiles (H2O, S, Cl, F) and trace elements in melt inclusions from the Kamchatka // Earth and Planetary Science Letters. 2007. Vol. 255. № 1-2. P. 53-69. doi: 10.1016/j.epsl.2006.12.005.
New and published data on the composition of melt inclusions in olivine (Fo73_yi) from volcanoes of the Kamchatka and northern Kurile Arc are used 1) to evaluate the combined systematics of volatiles (H2O, S, Cl, F) and incompatible trace elements in their parental magmas and mantle sources, 2) to constrain thermal conditions of mantle melting, and 3) to estimate the composition of slab-derived components. We demonstrate that typical Kamchatkan arc-type magmas originate through 5-14% melting of sources similar or slightly more depleted in HFSE (with up to -1 wt.% previous melt extraction) compared to MORB-source mantle, but strongly enriched in H2O,B, Be, Li, Cl. F, LILE, LREE, Th and U. Mean H2O in parental melts f 1.8-2.6 wt.%) decreases with increasing depth to the subducting slab and correlates negatively with both 'fluid-immobile* (e.g. Ti, Na, LREE) and most 'fluid-mobile' (e.g. LILE, S, Cl, F) incompatible elements, implying that solubility in hydrous fluids or amount of water does not directly control the abundance of 'fluid-mobile' incompatible elements. Strong correlation is observed between H2O/Ce and B/Zr (or B/LREE) ratios. Both, calculated H2O in mantle sources (0.1-0.4%) and degrees of melting (5-14%) decrease with increasing depth to the slab indicating that the ultimate source of water in the sub-arc mantle is the subducting oceanic plate and that water flux (together with mantle temperature) governs theextent of mantle melting beneath Kamchatka. A parameterized hydrous melting model [Katzetal. 2003, G3,4(9), 1073] is utilized to estimate that mantle melting beneath Kamchatka occurs at or below the dry peridotite solidus (1245-1330 °C at 1.5-2.0 GPa). Relatively high mantle temperatures (yet lower than beneath back-arc basins and ocean ridges) suggest substantial corner flow driven mantle upwelling beneath Kamchatka in agreement with numerical models implying non-isoviscous mantle wedge rheology. Data from Kamchatka, Mexico and Central America indicate that <5% melting would lake place beneath continental arcs without water flux from the subducting slab. A broad negative correlation appears to exist between crustal thickness and the temperature of magma generation beneath volcanic arcs with larger amounts of decompression melting occurring beneath thinner arc crust (Uihosphere). In agreement with the high mantle temperatures, we observe a systematic change in the composition of slab components with increasing slab depth from solute-poor hydrous fluid beneath the volcanic front to solute-rich hydrous melt or supercritical liquid at deeper depths beneath the rear arc. The solute-rich slab component dominates the budget of LILE, LREE,Th and U in the magmas and originates through wet-melting of subducted sediments and/or altered oceanic crust at > 120 km depth. Melting of the upper parts of subducting plates under water flux from deeper luhosphere (e.g. serpentinites), combined with high .emperatures in the mantie wedge, may be a more common process beneath volcanic arcs than has been previously recognized. 0 2006 Klsevier B.V. All rights reserved.
Portnyagin Maxim, Hoernle Kaj, Plechov Pavel, Mironov Nikita, Khubunaya Sergey Constraints on mantle melting and composition and nature of slab components in volcanic arcs from volatiles (H2O, S, Cl, F) and trace elements in melt inclusions from the Kamchatka Arc // Earth and Planetary Science Letters. 2007. Т. 255. № 1-2. С. 53-69. doi:10.1016/j.epsl.2006.12.005.
Turner Simon, Sims Kenneth W.W., Reagan Mark, Cook Craig A 210Pb–226Ra–230Th–238U study of Klyuchevskoy and Bezymianny volcanoes, Kamchatka // Geochimica et Cosmochimica Acta. 2007. Vol. 71. № 19. P. 4771 - 4785. doi: 10.1016/j.gca.2007.08.006.
Lavas from Klyuchevskoy and Bezymianny volcanoes, Kamchatka, appear to show a link between the extent of partial melting in their mantle source region and the subsequent degree of fractionation suffered by the magmas during passage through the crust. This fractionation may have occurred on timescales significantly less than 1000 years if observed 226Ra excesses largely reflect variable residual porosity in the source melting region. Unlike most arc lavas, those with the highest MgO contents and Ba/Th ratios have the lowest 226Ra excess. Forward models suggest that those portions of the source which had undergone the greatest addition of U by fluids from the subducting plate also underwent the greatest extents of partial melting at the highest residual porosity. At Kluchevskoy, a change from eruption of high-MgO to high-Al2O3 basaltic andesites around 1945 is reflected in an increase in size of 226Ra excess which seems to require a simultaneous decrease in residual porosity and suggests a rapid changes in the melting regime. The eruption of andesites at Bezyminanny, simultaneous with the eruption of basaltic andesites at Klyuchevskoy, further suggests that different degree melts produced at differing residual porosity can be formed and extracted from the melt region at the same time. Thus, the melting processes beneath Klyuchevskoy and Bezyminanny are demonstrably complex. They have clearly been influenced by both fluid addition from the subducting plate and extension and decompression beneath the Central Kamchatka Depression. Finally, the 210Pb data are, with one or two exceptions, in equilibrium with 226Ra, suggesting that there was restricted relative magma-gas movement in this highly productive magmatic system.
Walter Thomas R. How a tectonic earthquake may wake up volcanoes: Stress transfer during the 1996 earthquake–eruption sequence at the Karymsky Volcanic Group, Kamchatka // Earth and Planetary Science Letters. 2007. Vol. 264. № 3–4. P. 347 - 359. doi: 10.1016/j.epsl.2007.09.006.
A large tectonic earthquake occurred on Kamchatka peninsular on New Year's Day of 1996 along a SW–NE trending fracture system. Just two days after the earthquake and at a distance of about 10–20 km to the north, a simultaneous eruption of two separate volcanoes followed. These were Karymsky Volcano and Akademia Nauk Volcano, the latter having its first eruption in historical records. In this paper I use numerical models in order to elaborate the static stress transfer between the earthquake and the volcanic system during the sequence that culminated in the January 1996 volcano-tectonic events. The models were designed to consider (i) the geodetically identified pre-eruptive period of doming in order to calculate stress changes at the nearby SW–NE trending fracture zone, and (ii) the January 1996 Mw 7.1 earthquake in order to calculate the dilatation and stress changes at the magma plumbing system. The results suggest that stress changes related to year-long inflation under the volcanic centers increased the Coulomb failure stress at the active faults and thus encouraged the earthquake. The earthquake, in turn, prompted dilatation at the magmatic system together with extensional normal stress at intruding N–S trending dikes. Also, field measurements confirmed the presence of N–S oriented fractures above the dike. Unclamping of the N–S oriented fractures allowed magma to propagate and eventually to trigger the twin-eruption at the volcanoes Karymsky and Akademia Nauk. These findings imply that successful hazard evaluations at volcanoes elsewhere require consideration of the seismo-tectonic framework and large earthquake cycles.
Zaretskaya N.E., Ponomareva V.V., Sulerzhitsky L.D. Radiocarbon dating of large Holocene volcanic events within South Kamchatka (Russian Far East) // Radiocarbon. 2007. Vol. 49. № 2. P. 1065-1078.
Radiocarbon dating is widely used when studying recent volcanic activity in the Kamchatka Peninsula due to the abundance of organic matter that is associated with the volcanic deposits. Here, we present the results of 14C dating of major volcanic events within the active South Kamchatka volcanic zone. South Kamchatka includes 8 recently active volcanic centers (stratovolcanoes, calderas, and large craters) that have been erupting during the Holocene. Their tephras represent useful markers for both the southern part of the peninsula and the Northern Kurile Islands. Since these marker tephra layers facilitate stratigraphic and tephrochronological studies in this area, it was important to determine their ages. We have obtained 73 new individual 14C dates on paleosol, peat, charcoal, and wood associated with the marker tephra layers, then complemented these data with 37 earlier published dates and analyzed the resulting data set. We selected the reliable dates and then obtained average 14C ages of marker tephra layers. The details of these procedures, as well as brief descriptions of South Kamchatka Holocene eruptions and their tephra beds, are presented in the paper.
Андреев В.И., Озеров А.Ю., Сенюков С.Л., Гавриленко M.Г. Эруптивная активность вулкана Карымский в 2005-06 гг. // Материалы ежегодной конференции, посвященной Дню вулканолога, Петропавловск-Камчатский, 28-31 марта 2007 г. Петропавловск-Камчатский: ИВиС ДВО РАН. 2007. С. 337-346.
Вергасова Л.П., Кирсанова Т.П., Философова Т.М., Бойкова И.А. Об алунитизации в кратере вулкана Молодой Шивелуч (Северная группа вулканов, Камчатка) // Вестник КРАУНЦ. Серия: Науки о Земле. 2007. Вып. 9. № 1. С. 51-60.
Викулин А.В., Водинчар Г.М., Мелекесцев И.В., Акманова Д.Р., Осипова Н.А. Моделирование геодинамических процессов окраины Тихого океана // IV Международная конференция «Солнечно-земные связи и предвестники землетрясений». Петропавловск-Камчатский: ИКИР ДВО РАН. 2007. С. 275-280.
Modern scientists suppose that the Earth may be one whole “living” formation and all its
phenomena are closely connected. To reveal and research the peculiarities of the geodynamic
movements we made the database. It includes all known data on earthquakes and volcano eruptions of
the Earth. We used the volume of the erupted products to characterize the “energy” of eruption. Not
less than 80-90% of all eruptions and earthquakes occur within the Pacific margin. We collected new
data on earthquakes migration for this region and revealed that volcano eruptions are also apt to
migrate. It turned out that the migrational rates of the strongest earthquakes and eruptions are
comparable in series of their value rates. This fact allows suggesting that the migrational waves of
seismic and volcanic activity display the greater global geodynamic process. This process has different
“colours” in different geophysical fields.
The data allows using the obtained space-time peculiarities of distribution for the seismic and volcanic
activity as the basis for the more general geodynamic model.