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11.
Fumarolic activity of Avachinsky and Koryaksky volcanoes, Kamchatka, from 1993 to 1994 总被引：1，自引：0，他引：1
Yuri A. Taran Charles B. Connor Vyacheslav N. Shapar Alexandre A. Ovsyannikov Arthur A. Bilichenko 《Bulletin of Volcanology》1997,58(6):441-448
Volcanic gas and condensate samples were collected in 1993–1994 from fumaroles of Koryaksky and Avachinsky, basaltic andesite
volcanoes on the Kamchatka Peninsula near Petropavlovsk–Kamchatsky. The highest-temperature fumarolic discharges, 220 °C
at Koryaksky and 473 °C at Avachinsky, are water-rich (940–985 mmol/mol of H2O) and have chemical and isotopic characteristics typical of Kamchatka–Kurile, high- and medium-temperature volcanic gases.
The temperature and chemical and water isotopic compositions of the Koryaksky gases have not changed during the past 11 years.
They represent an approximate 2 : 1 mixture of magmatic and meteoric end members. Low-temperature, near-boiling-point discharges
of Avachinsky Volcano are water poor (≈880 mmol/mol); Their compositions have not changed since the 1991 eruption, and are
suggested to be derived from partially condensed magmatic gases at shallow depth. Based on a simple model involving mixing
and single-step steam separation, low water and high CO2 contents, as well as the observed Cl concentration and water isotopic composition in low-temperature discharges, are the
result of near-surface boiling of a brine composed of the almost pure condensed magmatic gas. High methane content in low-temperature
Avachinsky gases and the 220 °C Koryaksky fumarole, low C isotopic ratio in CO2 at Koryaksky (–11.8‰), and water isotope data suggest that the "meteoric" end member contains considerable amounts of the
regional methane-rich thermal water discovered in the vicinity of both volcanoes.
Received: 2 May 1996 / Accepted: 5 November 1996 相似文献
12.
１９９３年第四季度，全球地震活动为中等水平，三个月内共发生三次７．１级浅源地震。新几内亚东部发生６－７级地震多次。美州地震带地震活动表现不强。堪察加以东近海发生７．１级地震。亚欧带于１０月２日发生中国新疆南部（若羌）地震。全球浅源地震相对活跃。 相似文献
13.
14.
Surface Heat Balance and Spatially Distributed Ablation Modelling at Koryto Glacier, Kamchatka Peninsula, Russia 总被引：1，自引：0，他引：1
Keiko Konya Takane Matsumoto Renji Naruse 《Geografiska Annaler: Series A, Physical Geography》2004,86(4):337-348
To investigate the characteristics of ablation at Koryto Glacier, a mountain glacier under maritime climate in Kamchatka Peninsula, Russia, we made field observations from August to early September 2000. At a site near the equilibrium line, the 31‐day average net radiation, sensible heat flux, and latent heat flux were 43, 59 and 31 W?2, respectively. We developed a new distributed ablation model, which only needs measurements of air temperature and global radiation at one site. Hourly ablation rates at this site obtained by the energy balance method are related to measured air temperature and global radiation by linear multiple regression. A different set of multiple regression coefficients is fitted for snow and ice surfaces. Better estimates of ablation rate can be obtained by this approach than by other temperature index models. These equations are then applied to each grid cell of a digital elevation model to estimate spatially distributed hourly melt. Air temperature is extrapolated using a constant temperature lapse rate and global radiation is distributed considering topographic effects. The model enables us to calculate the hourly spatial distribution of ablation rates within the glacier area and could well provide a realistic simulation of ablation over the whole glacier. 相似文献
15.
Abstract. The Mutnovskoe deposit located in the Porozhisto‐Asachinskaya metallogenic province of South Kamchatka, Russia, is a polymetallic vein and Au‐Ag quartz vein associated type of hydrothermal deposit. The Mutnovskoe deposit is located inside a paleo‐caldera structure at the center of the Mutnovsko‐Asachinskaya geothermal field of Pliocene ‐ Quaternary age, where active gold deposition is identified in hot spring precipitate. The Mutnovskoe deposit is subdivided into the north flank, the central flank and the south flank based on the vein distributions and mineral parageneses. The mineralized vein system is oriented N‐S hosted in diorite ‐ gabbroic diorite stock, volcanic rocks and sedimentary rocks of Miocene ‐ Pleistocene age. The mineralization stage I (polymetallic vein) mainly in the central and the south flanks is Zn‐Pb‐Cu‐Au‐Ag contained in sphalerite, galena and tetrahedrite‐tennantite group mineral. The stage II (Au‐Ag quartz vein) occurs in the north and the central flanks. The stage III (Mn‐sulfide and Mn‐Ca‐carbonate vein) occurs in the whole deposit area. Stage II is the typical Au‐Ag quartz‐adularia vein of low‐sulfidation type. Stage III is alabandite‐rhodochrosite‐quartz‐calcite vein. The K‐Ar ages are 1.3±0.1 Ma for stage I sericite in alteration zone, and 0.7±0.1 Ma for the stage II adularia in mineralized vein. Based on the fluid inclusion study, range of ore forming temperature of the Mutnovskoe deposit is 200 to 260d?C (av. 230d?C). Salinities of fluid inclusions indicate 2.2 to 5.7 wt% NaCl in sphalerite and 0.8 to 3.3 wt% NaCl in quartz for the stage I. Mineral paragenesis of the polymetallic vein (stage I) is characterized by a district zoning of tennantite and Cd‐rich sphalerite in the south flank and tetrahedrite and Mn‐rich sphalerite in the central flank, which is due to the fractional crystallizations of ore‐forming fluid. Depositional condition of the low sulfidation state is inferred for the Mutnovskoe deposit, where the polymetallic vein of the south flank is in relatively higher sulfidation state than the central flank. 相似文献
16.
William Harbert Sergei Sokolov Maxim Alexutin Kirill Krylov Vladimir Grigoriev Alexander Heiphetz 《Tectonophysics》2003,361(3-4):215-227
The northernmost Kamchatka Peninsula is located along the northwestern margin of the Bering Sea and consists of complexly deformed accreted terranes. Progressing inland from the northwestern Bering Sea, the Olyutorskiy, Ukelayat and Koryak superterranes (OLY, UKL and KOR) are crossed. These terranes were accreted to the backstop Okhotsk-Chukotsk volcanic-plutonic belt (OChVB) in northernmost Kamchatka. A sedimentary sequence of Albian to Maastrichtian age overlaps the terranes and units of the Koryak superterrane, and constrains their accretion time. A paleomagnetic study of blocks within the Kuyul (KUY) terrane of the Koryak superterrane was completed at two localities (Camp 2: λ=61.83°N, φ=165.83°E and Camp 3: λ=61.67°N, φ=164.75°E). At both localities, paleomagnetic samples were collected from Late Triassic (225–208 Ma) limestone blocks (2–10 m in outcrop height) within a melange zone. Although weak in remanent magnetization, two components of remanent magnetization were observed during stepwise thermal demagnetization at 32 sites. The A component of magnetization was observed between room temperature and approximately 250 °C. This magnetic component is always of downward directed inclination and shows the best grouping at relatively low degrees of unfolding. Using McFadden–Reid inclination-only statistics and averaging all site means, the resulting A component mean is Iopt=60.3°, I95=5.0° and n=36 (sites). The B magnetic component is observed up to 565 °C, at which temperature, most samples have no measurable remanent magnetization, or growth of magnetic minerals has disrupted the thermal demagnetization process. Combining sites with Fisher estimates of kappa (k-value)≥13 and n (sites)≥3, where bedding orientation differs within a block, most of these sites show the best grouping of B component directions at 100% unfolding, and two of the blocks display remanent magnetizations of both upward and downward directed magnetic inclination. Combining sites with Fisher estimates of kappa (k-value)≥13 and n (sites)≥3, the resulting overall B component paleolatitude and associated uncertainty are λobs=30.4°N or S, λ95=8.9° and n=19 (sites). When compared with the expected North America paleolatitude of λAPWP expected=57.9°N, our data support a model in which blocks within the Koryak superterrane are allochthonous and far travelled. 相似文献
17.
Abstract. The Rodnikovoe gold deposit situated in a presently active hydrothermal system located north of the Mutnovsko-Asachinskaya geothermal area in southern Kamchatka, Far Eastern Russia, consists of typical low-sulfidation quartz-adularia veins in a host rock of diorite. The age of the mineralization was dated by the K-Ar method as 0.9 to 1.1 Ma based on adular-ia collected from the veins. Representative ore minerals in the deposit are electrum, argentite, aguilarite, polybasite, pearceite and lenaite. Dominant alteration minerals are adularia, α-cristobalite, chlorite, illite and kaolinite. Hydrothermal solutions of neutral pH were responsible for the mineralization, which is divided into six stages defined by tectonic boundaries. Gold mineralization occurred in stages I and III. Hydrothermal brecciation occurred during stages III, IV and VI. Stages II, IV, V and VI were barren. The estimated ore formation temperature based on a fluid inclusion study is 150 to 250 °C at a depth of approximately 170 m below the paleo-water table. Boiling of hydrothermal fluids is hypothesized as the cause of the intermittent deposition of gold ore. The sulfur and oxygen fugacities during the deposition of anhydrite prior to the hydrothermal brecciation were higher than those during the gold mineralization stages. The occurrence in the hydrothermal breccia of fragments of high grade Au-Ag and polymetallic ores suggests that higher grade mineralization of these metal ores might have occurred in a deeper portion of the deposit. 相似文献
18.
Tatiana Churikova Gerhard Wörner Nikita Mironov Andreas Kronz 《Contributions to Mineralogy and Petrology》2007,154(2):217-239
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.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
19.
A. E. Shantser 《Stratigraphy and Geological Correlation》2007,15(5):525-535
“Volcanogenic Complex” as a stratigraphic term is substantiated. Also discussed are peculiarities of the volcanic process, the nature and evolution time of the volcanic structures, the complete and incomplete volcanic cycles. Data of comprehensive geological, stratigraphic and paleovolcanologic study are used to subdivide the Kinkil’skii Formation of Paleogene volcanogenic rocks in the northwestern Kamchatka, which has undivided previously, into the Shamanka, Rebro, Bozhedomova, and Geeklen volcanogenic complexes of concurrent or different ages. As a result, two epochs of volcanism (the late Ypresian-Lutetian and late Bartonian-Priabonian) are distinguished. A hiatus separating the epochs was a time of intense scouring and leveling the landforms and of the weathering crust formation. In conclusions, some problems of the paleogeography in Kamchatka and adjacent territories are discussed. 相似文献
20.
A. V. Solov’ev T. N. Palechek M. N. Shapiro S. A. Johnston J. I. Garver D. M. Ol’shanetskii 《Stratigraphy and Geological Correlation》2007,15(1):112-119
In the Sredinnyi Range of Kamchatka, the Baraba Formation of continental conglomerates is assumed to be of the late Campanian age based on found flora remains, but data of isotopic geochronology suggest the Eocene age of these deposits. New data on radiolarians from cherty pebbles are considered in this work along with results of fission-track dating of zircons from pebbles and matrix of the Baraba conglomerates. Fission-track dates obtained for zircons from matrix approve the Eocene age of the Baraba Formation, and new dates characterizing pebbles are not contradicting this conclusion. The Baraba Formation structural position can hardly be lower, therefore, than that of the Irunei Formation. 相似文献