Записей: 2276
Churikova Tatiana, Wörner Gerhard, Mironov Nikita, Kronz Andreas Volatile (S, Cl and F) and fluid mobile trace element compositions in melt inclusions: implications for variable fluid sources across the Kamchatka arc // Contributions to Mineralogy and Petrology. 2007. V. 154. № 2. P. 217-239. doi:10.1007/s00410-007-0190-z.    Аннотация
Volatile element, major and trace element compositions were measured in glass inclusions in olivine from samples across the Kamchatka arc. Glasses were analyzed in reheated melt inclusions by electron microprobe for major elements, S and Cl, trace elements and F were determined by SIMS. Volatile element–trace element ratios correlated with fluid-mobile elements (B, Li) suggesting successive changes and three distinct fluid compositions with increasing slab depth. The Eastern Volcanic arc Front (EVF) was dominated by fluid highly enriched in B, Cl and chalcophile elements and also LILE (U, Th, Ba, Pb), F, S and LREE (La, Ce). This arc-front fluid contributed less to magmas from the central volcanic zone and was not involved in back arc magmatism. The Central Kamchatka Depression (CKD) was dominated by a second fluid enriched in S and U, showing the highest S/K2O and U/Th ratios. Additionally this fluid was unusually enriched in 87Sr and 18O. In the back arc Sredinny Ridge (SR) a third fluid was observed, highly enriched in F, Li, and Be as well as LILE and LREE. We argue from the decoupling of B and Li that dehydration of different water-rich minerals at different depths explains the presence of different fluids across the Kamchatka arc. In the arc front, fluids were derived from amphibole and serpentine dehydration and probably were water-rich, low in silica and high in B, LILE, sulfur and chlorine. Large amounts of water produced high degrees of melting below the EVF and CKD. Fluids below the CKD were released at a depth between 100 and 200 km due to dehydration of lawsonite and phengite and probably were poorer in water and richer in silica. Fluids released at high pressure conditions below the back arc (SR) probably were much denser and dissolved significant amounts of silicate minerals, and potentially carried high amounts of LILE and HFSE.
Fedotov S.A., Sugrobov V.M., Utkin I.S., Utkina L.I. On the possibility of using heat stored in the magma chamber of the Avachinsky volcano and the surrounding rock for heat and power supply // Journal of Volcanology and Seismology. 2007. V. 1. № 1. P. 28-41. doi:10.1134/S0742046307010022.    Аннотация
The results of geological and geophysical studies, including recent ones, which make it possible to verify the existence of a liquid magma chamber below the Avachinsky volcano on Kamchatka, and to estimate the chamber depth and approximate dimensions, are analyzed. The heat stored in the host rock heated by the volcanic magma chamber from the time of chamber origination to the present is estimated, taking variable chamber dimensions during the process of evolution into account. The geological-geophysical prerequisites for using the thermal energy of the heated rock which surrounds the magma chamber to supply heat and power to Petropavlovsk-Kamchatskii are analyzed. The creation of an underground geothermal circulation system (fracture heat exchanger) using deep boreholes is proposed.
Girina O.A., Manevich A.G., Malik N.A., Melnikov D.V., Ushakov S.V., Demyanchuk Yu.V., Kotenko L.V. Active volcanoes of Kamchatka and Northern Kurils in 2005 // Journal of Volcanology and Seismology. 2007. V. 1. № 4. P. 237-247. doi: 10.1134/S0742046307040021.    Аннотация
In 2005, six major eruptions of four Kamchatka volcanoes (Bezymyannyi, Klyuchevskoy, Shiveluch, and Karymskii) occurred and the Avachinskii, Mutnovskii, and Gorelyi Kamchatka volcanoes and the Ebeko and Chikurachki volcanoes in northern Kurils were in a state of increased activity. Owing to a close collaboration between the KVERT project, Elizovo airport meteorological center, and volcanic ash advisory centers in Tokyo, Anchorage, and Washington (Tokyo, Anchorage, and Washington VAACs), all necessary measures for safe airplane flights near Kamchatka were taken and fatal accidents related to volcanic activity did not occur.
Khubunaya S.A., Gontovaya L.I., Sobolev A.V., Nizkous I.V. Magma Chambers beneath the Klyuchevskoy Volcanic Group // Journal of Volcanology and Seismology. 2007. V. 1. № 2. P. 98-118. doi: 0.1134/S0742046307020029.    Аннотация
A 3D velocity model of the Earth's crust beneath the Klyuchevskoy volcanic group has been constructed using the seismic tomography method. Anomalies of the velocity parameters related to the zones of magma supply to active volcanoes have been distinguished. Petrological data on the composition, temperature, and pressure of generation and crystallization of primary melts of Klyuchevskoy volcano magnesian basalts have been obtained. The primary melt corresponds to picrite (MgO = 13-14 wt %) with an ultimate saturation of SiO2 (49-50 wt %), a high H2O content (2.2-2.9%), and incompatible elements (Sr, Rb, Ba, Hf). This melt is formed at pressures of 15-20 kbar and temperatures of 1280--1320С . Its further crystallization proceeds in intermediate magma chambers at two discrete pressure levels (i.e., greater than 6, and 1-2 kbar). The results of the petrological studies are in good agreement with the seismotomographic model.

Поступила в редакцию 1. 11. 2006 г.
Методом сейсмической томографии построена объемная скоростная модель земной коры под Ключевской группой вулканов. Выделены аномалии скоростных параметров связанных с зонами магматического питания активных вулканов. Получены петрологические данные о составе, температуре и давлении генерации и кристаллизации родоначальных расплавов магнезиальных базальтов Ключевского вулкана. Родоначальный расплав отвечает пикриту (MgO=13-14%,мас) с предельным насыщением SiO2 (49-50%, мас.), высоким содержанием H2O (2,2-2.9%) и несовместимыми элементами (Sr, Rb, Ba, Hf). Он образуется при давлениях 15-20 кбар и температурах 1280-13200С. Его дальнейшая кристаллизация проходит в промежуточных магматических камерах при двух дискретных уровнях давлений (более 6 и 1-2 кбар). Результаты петрологических исследований находятся в хорошем соответствии с сейсмотомографической моделью.
Lees J., Symons N., Chubarova O., Gorelchik V., Ozerov A. Tomographic Images of Klyuchevskoy Volcano P-Wave Velocity // Geophysical Monograph Series. // Volcanism and Subduction: The Kamchatka Region. 2007. V. 172. P. 293-302.    Аннотация
Three-dimensional structural images of the P-wave velocity below the edifice of the great Klyuchevskoy group of volcanoes in central Kamchatka are derived via tomographic inversion. The structures show a distinct low velocity feature extending from around 20 km depth to 35 km depth, indicating evidence of magma ponding near the Moho discontinuity. The extensive low velocity feature represents, at least to some degree, the source of the large volume of magma currently erupting at the surface near the Klyuchevskoy group.
Maximov A.P., Puzankov M.Yu., Bazanova L.I. The Plumbing System at the Initial Period of the Young Cone Formation, Avachinsky Volcano (Kamchatka) // XXIV IUGG General Assembly. July 2-13, 2007, Perugia, Italy. 2007.
Neal C.A., Girina O.A., Senyukov S.L., Rybin A.V., Osiensky J., Hall T., Nelson K., Izbekov P. Eruption warning systems for aviation in Russia: a 2007 status report // 4th International Workshop on Volcanic Ash. Natural Hazards. New Zealand. 2007. 2007. P. 1-7.
Ozerov A.Yu. Experimental Studies for Modeling the Explosions of Basaltic Volcanoes // Volcanism and Subduction: The Kamchatka Region. // AGU Fall Meeting 2007. Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstracts. 2007. P. V12B-04.
Ozerov A.Yu., Firstov P.P., Gavrilov V.A. Periodicities in the dynamics of eruptions of Klyuchevskoi Volcano, Kamchatka // Geophysical Monograph Series. // Volcanism and Subduction: The Kamchatka Region. 2007. V. 172. P. 283-291.    Аннотация
Detailed studies of volcanic tremor envelopes with frequencies ranging from 5.5⋅10-6 to 2.5⋅10-2 Hz (50 hrs - 40 sec), recorded during the Klyuchevskoi volcano eruptions of 1983 and 1984, revealed five major frequencies: 1.1⋅10-2 Hz (T1 = 1 min 34 sec), 2.5⋅10-3 Hz (T2 = 6 min 10 sec), 4.2⋅10-4 Hz (T3 = 40 min), 5.1⋅10-5 Hz (T4 = 5 hrs 30 min), 7.7⋅10-6 Hz (T5 = 36 hrs), as well as superpositions of their harmonics. In the 1993 eruption, fluctuations in the volcanic tremor envelopes have frequencies of TI = 2 hrs 48 min and TII = 6 hrs 12 min, which correspond to periodicities in the dynamics of eruptions identified by visual observations since 1932. The distribution of peak amplitudes has been found to vary in relation to eruption intensity—increasing eruption strength correlates with an increase in the amplitude of low frequency peaks, and vice versa. It is concluded that volcanic tremor allows monitoring of eruption dynamics. Possible reasons for the occurrence of periodicities are discussed, but a comprehensive model for this phenomenon has not yet been developed.
Ponomareva V., Kyle P., Pevzner M., Sulerzhitsky L., Hartman M. Holocene eruptive history of Shiveluch Volcano, Kamchatka Peninsula, Russia // Geophysical Monograph Series. // Volcanism and Subduction: The Kamchatka Region. 2007. V. 172. P. 263-282. № doi:10.1029/172GM19.    Аннотация
The Holocene eruptive history of Shiveluch volcano, Kamchatka Peninsula, has been reconstructed using geologic mapping, tephrochronology, radiocarbon dating, XRF and microprobe analyses. Eruptions of Shiveluch during the Holocene have occurred with irregular repose times alternating between periods of explosive activity and dome growth. The most intense volcanism, with frequent large and moderate eruptions occurred around 6500–6400 BC, 2250–2000 BC, and 50–650 AD, coincides with the all-Kamchatka peaks of volcanic activity. The current active period started around 900 BC; since then the large and moderate eruptions has been following each other in 50–400 yrs-long intervals. This persistent strong activity can be matched only by the early Holocene one.
Most Shiveluch eruptions during the Holocene produced medium-K, hornblendebearing andesitic material characterized by high MgO (2.3–6.8 wt %), Cr (47–520 ppm), Ni (18–106 ppm) and Sr (471–615 ppm), and low Y (> 18 ppm). Only two mafic tephras erupted about 6500 and 2000 BC, each within the period of most intense activity.
Many past eruptions from Shiveluch were larger and far more hazardous then the historical ones. The largest Holocene eruption occurred ∼1050 AD and yielded >2.5 km3 of tephra. More than 10 debris avalanches took place only in the second half of the Holocene. Extent of Shiveluch tephra falls exceeded 350 km; travel distance of pyroclastic density currents was > 22 km, and that of the debris avalanches ≤20 km.

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