Evidence of submarine hydrothermal discharge to the northwest of Guadeloupe Island (Lesser Antilles island arc)     

B.G. Polyak  Ph. Bouysse  V.I. Kononov  G.Yu. Butuzova  A. Criaud  V.I. Dvorov  M.D. Khutorskoy  V.G. Matveev  V.I. Paduchikh  E.P. Radionova  A.A. Rot  I.N. Tolstikhin  A.I. Voznesenskiy  V.P. Zverev 《Journal of Volcanology and Geothermal Research》1992,54(1-2)

During the Soviet-French survey carried out on board of the R.V. Akademik N. Strakhov, between Guadeloupe and Montserrat island in the central Lesser Antilles, evidence of submarine hydrothermal activity was discovered on the southeastern tip of the Shoe-Rock escarpment. The latter is part of a large, 130 km long, transverse structure, the Montserrat-Marie Galante fault, which crosses the Guadeloupe archipelago. Another locus of activity, probably of subdued importance nowadays, is represented by the d'Entrecasteaux dome, a small faulted seamount, located about 25 km to the SW of the former area.The evidence for hydrothermal activity is: (a) a wide range of values of conductive heat flow (q=6–11 mW/m²) and regular vertical variation at some sites with extreme values located close to the two above-mentioned features (average regional value, q = 105 mW/m², s.d. = 32); (b) occurrence of secondary mineralizations (todorokite, nontronite, etc.) replacing locally the primary matrix of basal upper Pliocene deposits; (c) geochemical anomalies in seawater near the sea bottom, showing enrichment in mantle-derived ³He (δ³He up to 10.2%), correlated with a sharp Zn anomaly (content up to 523 ppb).Further investigations along the submerged segments of the Montserrat-Marie Galante fault should probably lead to other discoveries of hydrothermal venting and/or mineralizations.  相似文献   

Development of a technique for IR spectroscopic determination of nitrogen content and aggregation degree in diamond crystals     

Lin Fang  O. V. Kononov  A. S. Marfunin  A. V. Tarasevich  B. N. Tarasevich 《Moscow University Geology Bulletin》2008,63(4):281-284

A technique for IR spectroscopic determination of the total nitrogen content N _S in the form of A-and B ₁-defects is suggested. It provides for the computer processing and decomposition of IR spectra into constituent bands, calculation of the total absorption band area S _N and individual areas S _A and S _B1 and their normalization with respect to the total area of the diamond intrinsic absorption S ₀, with the normalization coefficients K _S , K _A , and K _B1 being calculated. Based on the analysis of the IR spectra of 60 octahedral diamond crystals from the Mir and Yubileinaya pipes (Sakha-Yakutiya), the empirical functions N _S = 911.85 K _S ^0.9919 ppm (R ² = 0.9859), N _A = 1185.6 K _A ^1.1511 ppm (R ² = 0.8703), and N _B1 = 911.85 K _S ^0.9919 ? 1185.6 K _A ^1.1511 ppm have been defined.  相似文献   

The matter-flow structure in the SS Cyg system in its quiescent state from comparisons of observational and synthetic Doppler tomograms     

D. V. Bisikalo  D. A. Kononov  P. V. Kaigorodov  A. G. Zhilkin  A. A. Boyarchuk 《Astronomy Reports》2008,52(4):318-326

Doppler tomograms are constructed for the quiescent state of the SS Cyg system based on Hβ and Hγ spectral-line observations carried out in August 2006 with the 2-m telescope at Terskol Peak. Gasdynamical simulations combined with the Doppler tomograms enable identification of the main features of the flow. Comparisons of synthetic tomograms with observations indicate that an accretion disk is present in the quiescent system. In the tomograms, the luminosity is maximum at the arms of the spiral tidal shock at the shock front due to the interaction between the gas of the circum-binary envelope and material in the stream issuing from the Lagrangian point L₁ (the “hot line”), and in the region behind the bow shock due to the motion of the accretor and disk in the gas of the envelope. The contribution of this last element results in appreciable asymmetry of the tomograms.  相似文献   

New Evidence on the Relief of the Southern Underwater Slope in the South Baikal Basin     

O. M. Khlystov  E. E. Kononov  H. Minami  A. V. Kazakov  A. V. Khabuev  N. A. Gubin  A. G. Chenskii 《Geography and Natural Resources》2018,39(1):33-38

A high-resolution bathymetric survey of the entire underwater slope in South Baikal was carried out for the first time by means of the multibeam echosounder. New elements were revealed in the underwater relief of the southern slope of the basin from the Kultuchnaya river to the Mysovka river, and a relevant regionalization was carried out into three areas according to the presence of ancient landforms and the intensity of the processes of their reworking, with the boundaries along the delta-front and the river fan of the Utulik and Pereemnaya. We reconstructed the formation process of the modern relief of this area of the underwater slope and determined a dominant role of the underwater-erosion processes in the formation of the modern relief, with the tectonic movements served as the “trigger” for them. The study revealed a direct correlation between the reworking of the ancient geomorphological surfaces and the occurrence of separate large underwater elevations or group ridges (remnants), canyons and linear depressions. It is determined that the pivotal role in the appearance of the modern relief of the underwater slope in the second area of extensive plano-convex (in section) and fan-shaped (in plan) delta-fronts of large rivers and debris fans enveloping the remnants. The existence of a steep underwater slope from the mouth of the Pereemnaya to the mouth of the Bol’shaya Tel’naya and of two large benches, and also the proximity of the maximum depths of the southern basin at the foot of this slope are explained by a more intense step-like lowering of this part of the lake when compared with the western part of the basin. This also accounts for the absence of large remnants in this part of the slope. The area of occurrence of lacustrine-fluvial and lacustrine-delta deposits of the Tankhoi paleobasin within the southern basin of Baikal is reconstructed. Four new hydrate-bearing structures associated with these deposits and morphologically pronounced in the vertex parts of the remnants were discovered. The morphological exploration indicators of the presence of new accumulations of gas hydrates on the underwater slopes of Baikal have been expanded.  相似文献   

Tin–rare-earth element greisens of the Solnechnoe cassiterite–silicate deposit,Russian Far East     

P. G. Korostelev  V. G. Gonevchuk  N. V. Gorelikova  N. I. Ekimova  V. V. Kononov  T. L. Krylova  A. A. Orekhov  B. I. Semenyak  V. I. Suchkov 《Russian Journal of Pacific Geology》2016,10(1):63-77

The paper considers for the first time the morphology, composition, and conditions of formation of the greisens of the Solnechnoe deposit (Komsomol’sk ore district), a typical cassiterite–silicate assemblage. The greisens are localized in the root parts of the deposit and represent a system of veins and veinlets formed in the contraction fractures of the metasomatically altered roof of the monzogranite intrusion (age of 94–92 Ma). The cassiterite–chlorite–carbonate–muscovite–quartz composition of the greisens with admixture of topaz, fluorite, and apatite reflects the composition of the monzogranites. The greisens are close in age (85.3 Ma on muscovite) to the granitic aplites (80–85 Ma on the whole-rock and biotite) of the final phase of the intrusive magmatism. The fluid regime of their formation differs from that of the economic ores in higher temperature, pressure, and salinity. One distinguishing feature of the greisens is elevated contents of LREE, U, and Th, which are incorporated in the REE fluorcarbonates, thorite, and uranothorite crystallizing together with cassiterite.  相似文献   

Estimates of the temperatures of hydrocarbon generation in the region of the Sea of Okhotsk     

E. V. Verzhbitsky  Yu. M. Berlin  M. V. Kononov  M. M. Marina 《Oceanology》2006,46(4):534-544

Particular features of the tectonic structure and anomalous distribution of the geothermal, geomagnetic, and gravity fields in the region of the Sea of Okhotsk are considered. On the basis of heat flow data, the ages of large-scale structures in the Sea of Okhotsk are estimated at 65 Ma for the Central Okhotsk Rise and 36 Ma for the South Okhotsk Basin. The age of the South Okhotsk Basin is confirmed by the data on the kinematics and corresponds to a 50-km thickness of the lithosphere. This is in accordance with the thickness value obtained by magnetotelluric soundings. A comparative analysis of the model geothermal background and the measured heat flow values on the Akademii Nauk Rise is performed. The analysis points to an abnormally high (by approximately 20%) measured heat flow, which agrees with the high negative gradient of gravity anomalies. The estimates of the deep heat flow and the basement age of the riftogenic basins in the Sea of Okhotsk were carried out in the following areas: the Deryugin Basin (18 Ma, Early Miocene), the TINRO Basin (12 Ma, Middle Miocene), and the West Kamchatka Basin (23 Ma, Late Oligocene). The temperatures at the boundaries of the main lithological complexes of the sedimentary cover are calculated and the zones of oil and gas generation are defined. On the basis of geothermal, magnetic, structural, and other geological-geophysical data, a kinematic model of the region of the Sea of Okhotsk for a period of 36 Ma was calculated and constructed.  相似文献   

Thermodynamic Properties of Natural Cuspidine     

L. P. Ogorodova  M. F. Vigasina  O. V. Kononov  N. N. Koshlyakova  D. A. Ksenofontov  D. A. Khanin  V. D. Shcherbakov  L. V. Mel’chakova 《Geochemistry International》2018,56(8):865-869

The paper reports pioneering data on the calorimetrically determined enthalpy of formation from elements of cuspidine, Ca fluordiorthosilicate Ca₄Si₂O₇F₂, from the Tyrny-Auz Mo–W deposit in Kabardino- Balkaria, Russia. The data were obtained by high-temperature melt solution calorimetry. The determined value is ΔfH_el° (298.15 K) =–5190 ± 13 kJ/mol. The paper reports estimated S°(298.15 K) and Δ_fG_el° (298.15 K) of cuspidine.  相似文献   

Comparative Geodynamics of Aleutian and Izu–Bonin–Mariana Island-Arc Systems     

Chekhovich  V. D.  Sukhov  A. N.  Kononov  M. V.  Sheremet  O. G. 《Geotectonics》2019,53(1):24-41

Geotectonics - We have performed a comparative analysis of geological structure and geodynamic evolution of the nearly synchronous Izu–Bonin–Mariana and Aleutian island-arc systems. The...  相似文献   

A geodynamic model of the evolution of the Arctic basin and adjacent territories in the Mesozoic and Cenozoic and the outer limit of the Russian Continental Shelf     

N. P. Laverov  L. I. Lobkovsky  M. V. Kononov  N. L. Dobretsov  V. A. Vernikovsky  S. D. Sokolov  E. V. Shipilov 《Geotectonics》2013,47(1):1-30

The tectonic evolution of the Arctic Region in the Mesozoic and Cenozoic is considered with allowance for the Paleozoic stage of evolution of the ancient Arctida continent. A new geodynamic model of the evolution of the Arctic is based on the idea of the development of upper mantle convection beneath the continent caused by subduction of the Pacific lithosphere under the Eurasian and North American lithospheric plates. The structure of the Amerasia and Eurasia basins of the Arctic is shown to have formed progressively due to destruction of the ancient Arctida continent, a retained fragment of which comprises the structural units of the central segment of the Arctic Ocean, including the Lomonosov Ridge, the Alpha-Mendeleev Rise, and the Podvodnikov and Makarov basins. The proposed model is considered to be a scientific substantiation of the updated Russian territorial claim to the UN Commission on the determination of the Limits of the Continental Shelf in the Arctic Region.  相似文献   

Two-Level Subduction in the Upper Mantle as a Mechanism for the Evolution of the Eastern Arctic Lithosphere for the Late Jurassic–Early Cretaceous     

Lobkovskiy  L. I.  Sokolov  S. D.  Sorokhtin  N. O.  Kononov  M. V. 《Doklady Earth Sciences》2021,500(2):809-815

Doklady Earth Sciences - The popular rotational hypothesis of the formation and evolution of the main structures of the Eastern Arctic lithosphere during the Late Jurassic–Early Cretaceous,...  相似文献