Areas and sources of metasedimentary rocks in the Tukuringra terrane of the Mongolian–Okhotsk mobile belt: Results of Sm–Nd isotope study     

A. A. Sorokin  A. P. Sorokin  A. B. Kotov  V. P. Kovach  Yu. V. Plyaskin 《Doklady Earth Sciences》2016,470(1):961-964

The results of Sm–Nd studies of metasedimentary rocks from the Tukuringra terrane, one of the largest units in the structure of the eastern part of the Mongolian–Okhotsk mobile belt, are reported. Metasedimentary rocks of the Algainskaya, Garmakanskaya, and Teploklyuchevskaya formations are characterized by similar model ages t_Nd(DM) = 1.5–1.1 Ga. This shows that the major protoliths of metasedimentary rocks of the terrane are characterized by Mesoproterozoic estimates of the Nd model ages. The results obtained allow us to assume that introduction of terrigenous material into the sedimentary basin mostly occurred from the continental massifs united into the Amur superterrane, since their magmatic and sedimentary complexes are characterized by identical values of the Nd model ages.  相似文献   

Present state of the study of 160-minutes solar oscillation     

A. B. Severny  V. A. Kotov  T. T. Tsap 《Solar physics》1981,74(1):65-71

Global oscillation of the Sun with a period of 160 rain were first discovered in 1974 and since observed in Crimea during the last 6 years; they were confirmed, in 1976–1979, by Doppler measurements at Stanford (Scherrer et al., 1980) and quite recently by observations of Fossat and Grec at the south geographic pole. The average amplitude of the oscillation is about 0.5 m s^-1. The phase shows remarkable stability at the period 160.010 min and good agreement between different sites on the Earth; therefore, this oscillation should now be recognized as definitely of solar origin. It is probably accompanied by synchronous fluctuations in the IR brightness and radio-emission of the Sun, and exhibits a dependence of the amplitude on the phase of solar rotation (with a peak of power at 27.2 days).In agreement with results of the Birmingham group and the South Pole observation we also find evidence in favour of a discrete spectrum within the 5 min global oscillations of the Sun, with the average splitting of about 69.5 Hz in frequency.Strict gas-dynamical equations being solved in the adiabatic approximation for a polytropic sphere n = 3 display the pattern of radial oscillations with wave packets separated by 120 m time-intervals filled with high frequency (and split by 117 Hz) oscillations implying a similarity with the observed pattern.Proceedings of the 14th ESLAB Symposium on Physics of Solar Variations, 16–19 September 1980, Scheveningen, The Netherlands.  相似文献   

Mud volcanoes and gas vents in the Okhotsk Sea area   总被引：5，自引：0，他引：5  

Shakirov  Renat  Obzhirov  Anatoly  Suess  Erwin  Salyuk  Anatoly  Biebow  Nicole 《Geo-Marine Letters》2004,24(3):140-149

Gas emissions from mud volcanoes on Sakhalin Island and water-column gas flares arising from cold seeps in the Okhotsk Sea appear to be related. They are likely activated by tectonic movements along the transform plate boundary separating the Okhotsk Sea Plate from the Eurasian and Amur plates. Gas vents (flares) and methane anomalies occur in the waters offshore Sakhalin Island, along with NE-SW-trending mounds and fluid escape structures on the seafloor. The intersection of the NE-striking transverse faults on land with the Central Sakhalin and Hokkaido-Sakhalin shear zones apparently determines the sites of mud volcanoes, a pattern that continues offshore where the intersection with the East Sakhalin and West Derugin shear zones determines the sites of the submarine gas vents.  相似文献   

Climate-induced boreal forest change: Predictions versus current observations   总被引：4，自引：0，他引：4  

Amber J. Soja  Nadezda M. Tchebakova  Nancy H.F. French  Michael D. Flannigan  Herman H. Shugart  Brian J. Stocks  Anatoly I. Sukhinin  E.I. Parfenova  F. Stuart Chapin III  Paul W. Stackhouse  Jr. 《Global and Planetary Change》2007,56(3-4):274

For about three decades, there have been many predictions of the potential ecological response in boreal regions to the currently warmer conditions. In essence, a widespread, naturally occurring experiment has been conducted over time. In this paper, we describe previously modeled predictions of ecological change in boreal Alaska, Canada and Russia, and then we investigate potential evidence of current climate-induced change. For instance, ecological models have suggested that warming will induce the northern and upslope migration of the treeline and an alteration in the current mosaic structure of boreal forests. We present evidence of the migration of keystone ecosystems in the upland and lowland treeline of mountainous regions across southern Siberia. Ecological models have also predicted a moisture-stress-related dieback in white spruce trees in Alaska, and current investigations show that as temperatures increase, white spruce tree growth is declining. Additionally, it was suggested that increases in infestation and wildfire disturbance would be catalysts that precipitate the alteration of the current mosaic forest composition. In Siberia, 7 of the last 9 yr have resulted in extreme fire seasons, and extreme fire years have also been more frequent in both Alaska and Canada. In addition, Alaska has experienced extreme and geographically expansive multi-year outbreaks of the spruce beetle, which had been previously limited by the cold, moist environment. We suggest that there is substantial evidence throughout the circumboreal region to conclude that the biosphere within the boreal terrestrial environment has already responded to the transient effects of climate change. Additionally, temperature increases and warming-induced change are progressing faster than had been predicted in some regions, suggesting a potential non-linear rapid response to changes in climate, as opposed to the predicted slow linear response to climate change.  相似文献   

There are ten,not eight planets     

V. A. Kotov 《Bulletin of the Crimean Astrophysical Observatory》2007,103(1):75-81

In 1946, E. Sevin postulated the global vibrations of the Sun with a period P ₀ = 1/9 day and a “wavelength” L ₀ = c × P ₀ = 19.24 AU and predicted the tenth planet at a mean distance of 4.0 × L ₀ ≈ 77.0 AU from the Sun (c is the speed of light). The global vibrations of the Sun, precisely with the period of 1/9 day, were actually detected in 1974. Recently, the largest Kuiper Bell object 2003 UB₃₁₃, or Eris, with an orbital semimajor axis ≈ 3.5 × L ₀ ≈ 67.5 AU was discovered. We adduce arguments for the status of Eris as our tenth planet: (i) the object is larger and farther from the Sun than Pluto and (ii) the semimajor axis of Eris agrees well with the sequence of planetary distances that follows from the resonance spectrum of the Solar system dimensions (with the scale L ₀ and for all 11 orbits, including those of Pluto, Eris, and the asteroid belt). We point to a mistake of the Prague (2006) IAU Assembly, which excluded Pluto from the family of planets by introducing a new, highly controversial class of objects—“dwarf planets.”  相似文献   

Resolution of MRS applied to the characterization of hard-rock aquifers   总被引：4，自引：0，他引：4  

Legchenko A  Descloitres M  Bost A  Ruiz L  Reddy M  Girard JF  Sekhar M  Mohan Kumar MS  Braun JJ 《Ground water》2006,44(4):547-554

The performance of the Magnetic Resonance Sounding (MRS) method applied to the investigation of heterogeneous hard-rock aquifers was studied. It was shown using both numerical modeling and field measurements that MRS could be applied to the investigation of the weathered part of hard-rock aquifers when the product of the free water content multiplied by the thickness of the aquifer is >0.2 (for example, 10-m-thick layer with a 2% water content). Using a currently available one-dimensional MRS system, the method allows the characterization of two-dimensional subsurface structures with acceptable accuracy when the size of the subsurface anomaly is equal to or greater than the MRS loop. However, the fractured part of hard-rock aquifers characterized by low effective porosity (<0.5%) cannot be resolved using currently available MRS equipment. It was found that shallow water in the weathered part of the aquifer may screen MRS signals from deeper water-saturated layers, thus further reducing the possibility of investigating deeper fractured aquifers. A field study using the NUMIS(plus) MRS system developed by IRIS Instruments was carried out on an experimental watershed in southern India. A heterogeneous unconfined aquifer in a gneissic formation was successfully localized, and MRS results were confirmed by drilling shortly after the geophysical study. The top of the aquifer revealed by MRS was found to be in a good agreement with observed static water level measurements in boreholes.  相似文献   

The emptiness of voids: yet another overabundance problem for the Λ cold dark matter model     

Anton V. Tikhonov  Anatoly Klypin 《Monthly notices of the Royal Astronomical Society》2009,395(4):1915-1924

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Nd-Sr systematics of metamagmatic rocks of the Anginskaya and Talanchanskaya Formations,middle part of Lake Baikal     

V. A. Makrygina  I. V. Sandimirov  G. P. Sandimirova  Yu. A. Pakhol’chenko  A. B. Kotov  V. P. Kovach  A. V. Travin 《Geochemistry International》2010,48(10):979-987

The paper presents data on the Nd-Sr systematics of magmatic rocks of the Khaidaiskii Series of the Anginskaya Formation in the Ol’khon region, western Baikal area, and rocks of the Talanchanskaya Formation on the eastern shore of Lake Baikal. Geochemical characteristics of these rocks are identical and testify to their arc provenance. At the same time, the ɛ_Nd^tof rocks of the Khaidaiskii Series in the Ol’khon area has positive values, and the data points of these rocks plot near the mantle succession line in the ɛ_Nd^t-⁸⁷Sr/⁸⁶Sr diagram, whereas the ɛ_Nd^t values of rocks of the Talanchanskaya Formation are negative, and the data points of these rocks fall into the fourth quadrant in the ɛ_Nd^t-⁸⁷Sr/⁸⁶Sr diagram. This testifies to a mantle genesis of the parental magmas of the Khaidaiskii Series and to the significant involvement of older crustal material in the generation of the melts that produced the orthorocks on the eastern shore of the lake. These conclusions are corroborated by model ages of magmatic rocks in the Ol’khon area (close to 1 Ga) and of rocks of the Talanchanskaya Formation (approximately 2 Ga). The comparison of our data with those obtained by other researchers on the Nd-Sr isotopic age of granulites of the Ol’khon Group and metavolcanics in various structural zones in the northern Baikal area suggests, with regard for the geochemistry of these rocks, the accretion of tectonic nappes that had different isotopic histories: some of them were derived from the mantle wedge and localized in the island arc itself (magmatic rocks of the Anginskaya Formation) or backarc spreading zone (mafic metamagmatic rocks of the Ol’khon Group), while others were partial melts derived, with the participation of crustal material, from sources of various age (metagraywackes in the backarc basin in the Ol’khon Group and the ensialic basement of the island arc in the Talanchanskaya Formation).  相似文献   

Early cambrian ophiolites of the boshchekul zone (Central Kazakhstan): Structure of sections and age substantiation     

K. E. Degtyarev  A. V. Ryazantsev  A. B. Kotov  E. B. Sal’nikova  I. V. Anisimova  S. Z. Yakovleva 《Doklady Earth Sciences》2010,431(2):413-417

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Rare-metal granitoids of the Ulug-Tanzek deposit (Eastern Tyva): Age and tectonic setting     

Yarmolyuk  V. V.  Nikiforov  A. V.  Sal’nikova  E. B.  Travin  A. V.  Kozlovskiy  A. M.  Kotov  A. B.  Shuriga  T. N.  Lykhin  D. A.  Lebedev  V. I.  Anisimova  I. V.  Plotkina  Yu. V.  Yakovleva  S. Z. 《Doklady Earth Sciences》2010,430(1):95-100

Doklady Earth Sciences -  相似文献