Girina O.A. Pyroclastic surge deposits of Bezymianny volcano // IUGG. XXI General Assembly. Colorado. 1995. P. B 419
Kersting Annie B., Arculus Richard J. Pb isotope composition of Klyuchevskoy volcano, Kamchatka and North Pacific sediments: Implications for magma genesis and crustal recycling in the Kamchatkan arc // Earth and Planetary Science Letters. 1995. Vol. 136. № 3–4. P. 133 - 148. doi: 10.1016/0012-821X(95)00196-J.
Pb isotope data are used to constrain the chemical contribution of the subducted components in the recycling beneath Klyuchevskoy volcano, the most active volcano in the Kamchatkan arc. The Pb isotope ratios of Klyuchevskoy basalts (206Pb/204Pb= 18.26–18.30, 207/Pb204Pb= 15.45–15.48, 208/Pb204Pb= 37.83–37.91) define a narrow range that falls within the Pacific mid-ocean ridge basalt (MORB) field and are among the least radiogenic island arc basalts measured to date. These data are similar to data from three other Quaternary Kamchatkan volcanoes: Tolbachik, Kumroch-Shish, and Maly Semiachik. In contrast, North Pacific sediments (primarily siliceous oozes) collected parallel to the Kamchatkan trench during Ocean Drilling Program Leg 145, have Pb isotope ratios (206Pb/204Pb= 18.51–18.78, 207Pb/204Pb= 15.56–15.64, 208Pb/204Pb= 38.49–38.75) that are more radiogenic than either the Klyuchevskoy basalts or Pacific MORB. Incorporation of even a small amount of sediment in the source of the Klyuchevskoy magmas would shift the Pb isotope ratios of the erupted basalts from the MORB field to more radiogenic values. The absence of 10Be and elevated Pb isotope ratios in the Kamchatkan volcanic lavas, despite the presence of distinctively radiogenic Pb in the North Pacific sediments makes it unlikely that sediments or sediment-derived fluids are involved in the source magmas beneath Kamchatka. The Kamchatkan arc thus represents an “end-member” whereby little or no sediment is involved in terms of elemental recycling and arc magma genesis. The major and trace elements, Pb, Sr and Nd isotope data of the Kamchatkan basalts are most consistently explained if derived from a fluid-fluxed, peridotitic mantle wedge source, wherein the fluid composition is dominantly controlled by dehydration of altered oceanic crust, imparting a radiogenic 87Sr/86Sr, and MORB-like Pb isotope signature to the mantle source. The erupted Klyuchevskoy lavas preserve a slab signature derived from incompatible elements that are strongly partitioned into the fluid. The 30 km of arc crust through which the Klyuchevskoy magmas traverse prior to eruption is not composed of older crust, but must be juvenile, similar in isotopic composition to MORB.
Maximov A.P. Rheological burst as mechanism of andesitic pyroclastics formation // IUGG XXI Gener. Assemb.. 1995, Boulder, USA. 1995. P. B411
Melekestsev Ivan V., Ponomareva Vera V., Volynets Oleg N. Kizimen volcano, Kamchatka — A future Mount St. Helens? // Journal of Volcanology and Geothermal Research. 1995. Vol. 65. № 3-4. P. 205-226.
Miller T.P., Kirianov V.Yu. Volcanic Ash Hazard along the North Pacific (NOPAC) Air Routs: Kurile Islands - Kamchatka - Alaska // Proc. of the 95 International workshop on Volcanoes Commemorating the 50-th Anniversary of the Mt. Shova-Shinzan: Short papers and Abstracts. 1995.
Taran Yu.A., Hedenquist J.W., Korzhinsky M.A., Tkachenko S.I., Shmulovich K.I. Geochemistry of magmatic gases from Kudryavy volcano, Iturup, Kuril Islands // Geochimica et Cosmochimica Acta. 1995. Vol. 59. № 9. P. 1749 - 1761. doi: 10.1016/0016-7037(95)00079-F.
Volcanic vapors were collected during 1990–1993 from the summit crater of Kudryavy, a basaltic andesite volcano on Iturup island in the Kuril arc. The highest temperature (700–940°C) fumarolic discharges are water rich (94–98 mole% H2O and have δD values of −20 to −12%o. The chemical and water isotope compositions of the vapors (temperature of thirteen samples, 940 to 130°C) show a simple trend of mixing between hot magmatic fluid and meteoric water; the magmatic parent vapor is similar in composition to altered seawater. The origin of this endmember is not known; it may be connate seawater, or possibly caused by the shallow incorporation of seawater into the magmatic-hydrothermal system. Samples of condensed vapor from 535 to 940°C fumaroles have major element trends indicating contamination by wall-rock particles. However, the enrichment factors (relative to the host rock) of many of the trace elements indicate another source; these elements likely derive from a degassing magma. The strongest temperature dependence is for Re, Mo, W, Cu, and Co; highly volatile elements such as Cl, I, F, Bi, Cd, B, and Br show little temperature dependence. The Re abundance in high-temperature condensates is 2–10 ppb, sufficient to form the pure Re sulfide recently discovered in sublimates of Kudryavy. Anomalously high I concentrations (1–12 ppm) may be caused by magma-marine sediment interaction, as Br/I ratios are similar to those in marine sediments.
The high-temperature (>700°C) fumaroles have a relatively constant composition (∼2 mol% each C and S species, with SO2/H2S ratio of about 3:1, and 0.5 mol% HCl); as temperature decreases, both St and CI are depleted, most likely due to formation of native S and HCl absorption by condensed liquid, in addition to the dilution by meteoric water. Thermochemical evaluation of the high-temperature gas compositions indicates they are close to equilibrium mixtures, apart from minor loss of H2O and oxidation of CO and H2 during sampling. Calculation to an assumed equilibrium state indicates temperatures from 705 to 987°C. At high temperature (≈900°C), the redox states are close to the overlap of mineral (quartz-fayalite-magnetite and nickel-nickel oxide) and gas (H2OH2SO2H2S) buffer curves, due to heterogeneous reaction between the melt and gas species. At lower temperatures (<800°C), the trend of the redox state is similar to the gas buffer curve, probably caused by homogeneous reaction among gas species in a closed system during vapor ascent.
Taran Yuri, Yurova L.M. Volcanic-hydrothermal system of Baransky volcano, Iturup,
Kurile islands // IUGG XXI General Assembley. 1995. P. VA41C - 6.
Адушкин В.В., Зыков Ю.Н., Иванов Б.А. Численное моделирование лавинообразного обрушения вулкана Корякский // Вулканология и сейсмология. 1995. № 6. С. 82-93.
Арискин A.A., Бармин А.А., Озеров А.Ю. Модель образования высокоглиноземистых магма Ключевского вулкана // Материалы конференции "Российской фонд фундаментальных исследований в Сибирском регионе. Земная кора и литосфера". Иркутск: 1995.
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