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1.
M. A. Solovyeva A. V. Starovoytov G. G. Akhmanov O. M. Khlystov A. V. Khabuev M. Yu. Tokarev D. A. Chensky 《Moscow University Geology Bulletin》2016,71(6):416-428
As a result of careful interpretation of the data of recent seismo-acoustic surveys, two major seismic complexes were identified in the structure of the upper sedimentary section of the north-western slope of Kukuy Griva (ridge). They are composed of several inner seismo-facies, which are very characteristic and separated with well-expressed regional reflector. Seismic and acoustic data revealed evidences of numerous landslide processes which were different in age and peculiarities of manifestation. For the first time, detailed schemes of seismo-facies distribution are compiled for major seismic complexes at the area. The boundary between seismic complexes is dated as 150 thousands years. It is shown that sliding was more intensive during Late Pleistocene and Holocene, reflecting activation of tectonic movements in this part of Baikal rift system. 相似文献
2.
A.Yu. Manakov O.M. Khlystov A. Hachikubo A.G. Ogienko 《Russian Geology and Geophysics》2013,54(4):475-482
Earlier, the coexistence of spatially separated layers of gas hydrates of cubic structures I and II (CS-I, CS-II) in the bottom sediment cores from K-2 mud volcano (Kukui Canyon, Lake Baikal) was described. The layers of gas hydrates of different structural types were situated at different depths and overlain by the lacustrine sediments. Hydrate of CS-II contained 13–15 mol.% ethane, whereas CS-I hydrate contained only 3–4 mol.% ethane. We present a physicochemical model explaining the formation of such an unusual natural object. The model suggests that only CS-I hydrate was originally present at the sampling site. Some geologic event (tectonic shifts, landslide, etc.) stopped natural-gas emanation from the mud volcano or increased the heat flow in the hydrate pool. As a result, CS-I hydrate began to dissolve in interstitial water. We assume that the ethane-enriched CS-II hydrate is an intermediate product of the dissociation (dissolution) of CS-I hydrate. 相似文献
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4.
A. A. Krylov O. M. Khlystov T. I. Zemskaya H. Minami A. Hachikubo H. Shoji M. Kida T. P. Pogodaeva L. Naudts J. Poort 《Geochemistry International》2008,46(10):985-995
This paper presents data on authigenic siderite first found in surface sediments from mud volcanoes in the Central (K-2) and Southern (Malen’kii) basins of Lake Baikal. Ca is the predominant cation, which substitutes Fe in the crystalline lattice of siderite. The enrichment of the carbonates in the 13C isotope (from +3.3 to +6.8‰ for the Malen’kii volcano and from +17.7 to +21.9‰ for K-2) results from the crystallization of the carbonates during methane generation via the bacterial destruction of organic matter (acetate). The overall depletion of the carbonates in 18O is mainly inherited from the isotopic composition of Baikal water. 相似文献
5.
Krylov Alexey A. Hachikubo Akihiro Minami Hirotsugu Pogodaeva Tatyana V. Zemskaya Tamara I. Krzhizhanovskaya Mariya G. Poort Jeffrey Khlystov Oleg M. 《International Journal of Earth Sciences》2018,107(6):2011-2022
International Journal of Earth Sciences - Early diagenetic carbonates are rare in Lake Baikal. Siderite (Fe carbonate) concretions in the sediments were discovered only recently. Here, we discuss... 相似文献
6.
Ceramicola S. Rebesco M. De Batist M. Khlystov O. 《Marine Geophysical Researches》2001,22(5-6):445-464
High resolution, single-channel seismic sparker profiles across the Akademichesky Ridge, an intra-basin structural high in Lake Baikal (Russia), reveal the presence of small sediment mounds and intervening moats in the upper part of the sedimentary cover. Such features interrupt the generally uniform and even acoustic facies and are not consistent with the hemipelagic sedimentation, which is expected on such an isolated high and which would produce a uniform sediment drape over bottom irregularities. The influence of turbidity currents is excluded since the ridge is an isolated high elevated more than 600-1000 m above adjacent basins. The mounded seismic facies, including migrating sediment waves and non-depositional/erosional incisions, strongly suggest that sediment accumulation was controlled by bottom-current activity. We interpret the mounds as small-scale (< few tens of km2 in area) lacustrine drifts. Four basic types of geometry are identified: 1) slope-plastered patch sheets; 2) patch drifts; 3) confined drifts; 4) fault-controlled drifts. The general asymmetry in the sedimentary cover of the ridge, showing thicker deposits on the NW flank, and the common location of patch drifts on the northeast side of small basement knolls indicate that deposition took preferentially place at the lee sides of obstacles in a current flowing northward or sub-parallel to the main contours. Deep-water circulation in the ridge area is not known in detail, but there are indications that relatively cold saline water masses are presently flowing out of the Central Basin and plunging into the deep parts of the North Basin across the ridge, a process that appears to be driven mainly by small differences in salinity. We infer that the process responsible for the observed bottom-current-controlled sedimentary features has to be sought in these large-scale water-mass movements and their past equivalents. The age of the onset of the bottom-current-controlled sedimentation, based on an average sedimentation rate of 4.0 cm/ky, is roughly estimated to be as least as old as 3.5 Ma, which is generally regarded as the age of the onset of the last major tectonic pulse of rift basin development in the Baikal region. 相似文献
7.
Jeffrey Poort Oleg M. Khlystov Lieven Naudts Albert D. Duchkov Hitoshi Shoji Shin’ya Nishio Marc De Batist Akihiro Hachikubo Masato Kida Hirotsugu Minami Andrey Y. Manakov Marina V. Kulikova Alexey A. Krylov 《Geo-Marine Letters》2012,32(5-6):407-417
Thermal measurements and hydrate mapping in the vicinity of the K-2 mud volcano in Lake Baikal have revealed a particular type of association of thermal anomalies (29–121?mW?m–2) near hydrate-forming layers. Detailed coring within K-2 showed that hydrates are restricted to two distinct zones at sub-bottom depths exceeding 70–300?cm. Temperature data from stations with hydrate recovery and degassing features all display low thermal gradients. Otherwise, the thermal gradients within the mud volcano are generally increased. These findings imply a more complicated thermal regime than often assumed for mud volcanoes, with important roles for both fluids and hydrates. The coexistence of neighbouring low and high thermal anomalies is interpreted to result from discharging and recharging fluid activity, rather than hydrate thermodynamics. It is suggested that hydrates play a key role in controlling the fluid circulation pattern at an early stage. At a later stage, the inflow of undersaturated lake water would favour the dissolution of structure I hydrates and the formation of structure II hydrates, the latter having been observed on top of structure I hydrates in the K-2 mud volcano. 相似文献
8.
Multi-Wavelength Synchrotron Radiation XRF Determination of U and Th in Sedimentary Cores from Lake Baikal 总被引:1,自引:0,他引:1
Michael A. Phedorin Evgeny L. Goldberg Vladislav A. Bobrov Oleg M. Khlystov Michael A. Grachev 《Geostandards and Geoanalytical Research》2000,24(2):217-226
A new technique for the determination of uranium and thorium in lacustrine sediments is based on non-destructive synchrotron radiation X-ray fluorescence analysis (SR-XRF) of sediment samples using monochromatic beams of different energies as excitation sources, with the recording and subsequent iterative processing of the X-ray fluorescence spectra. The technique has a multielement capability and enables fast, simultaneous analysis of a few tens of elements. The proposed SR-XRF technique was tested against INAA and ICP-MS methods and showed a number of advantages with a generally good correlation of results by the three methods. Uranium and Th profiles have been measured at a time resolution of 2 kyr in a drill core (BDP-96) from Lake Baikal bottom sediments deposited between 780 and 40 kyr B P. During this time span, peaks in the U and U/Th concentration marked warm climates. Oscillations of U and U/Th in Baikal bottom sediments during the Brunhes chron reflect climate-induced global change in the volume of polar ice, controlled by long-term cyclicity of the Earths orbital parameters. The response of these warm periods is similar to that observed earlier in shorter cores that span the two last interglacials (220-0 kyr BP). 相似文献
9.
Akihiro Hachikubo Oleg Khlystov Masato Kida Hirotoshi Sakagami Hirotsugu Minami Satoshi Yamashita Nobuo Takahashi Hitoshi Shoji Gennadiy Kalmychkov Jeffrey Poort 《Geo-Marine Letters》2012,32(5-6):419-426
This study reports measurements of the Raman spectra of Lake Baikal gas hydrates and estimations of the hydration number of methane-rich samples. The hydration number of gas hydrates retrieved from the southern Baikal Basin (crystallographic structure I) was approx. 6.1. Consistent with previous results, the Raman spectra of gas hydrates retrieved from the Kukuy K-2 mud volcano in the central Baikal Basin indicated the existence of crystallographic structures I and II. Measurements of the dissociation heat of Lake Baikal gas hydrates by calorimetry (from the decomposition of gas hydrates to gas and water), employing the hydration number, revealed values of 53.7–55.5?kJ?mol–1 for the southern basin samples (structure I), and of 54.3–55.5?kJ?mol–1 for the structure I hydrates and 62.8–64.2?kJ?mol–1 for the structure II hydrates from the Kukuy K-2 mud volcano. 相似文献
10.
Akihiro Hachikubo Oleg Khlystov Alexey Krylov Hirotoshi Sakagami Hirotsugu Minami Yutaka Nunokawa Satoshi Yamashita Nobuo Takahashi Hitoshi Shoji Shin’ya Nishio Masato Kida Takao Ebinuma Gennadiy Kalmychkov Jeffrey Poort 《Geo-Marine Letters》2010,30(3-4):321-329
We investigated the molecular composition (methane, ethane, and propane) and stable isotope composition (methane and ethane) of hydrate-bound gas in sediments of Lake Baikal. Hydrate-bearing sediment cores were retrieved from eight gas seep sites, located in the southern and central Baikal basins. Empirical classification of the methane stable isotopes (δ13C and δD) for all the seep sites indicated the dominant microbial origin of methane via methyl-type fermentation; however, a mixture of thermogenic and microbial gases resulted in relatively high methane δ13C signatures at two sites where ethane δ13C indicated a typical thermogenic origin. At one of the sites in the southern Baikal basin, we found gas hydrates of enclathrated microbial ethane in which 13C and deuterium were both highly depleted (mean δ13C and δD of –61.6‰ V-PDB and –285.4‰ V-SMOW, respectively). To the best of our knowledge, this is the first report of C2 δ13C–δD classification for hydrate-bound gas in either freshwater or marine environments. 相似文献