Doklady Earth Sciences
Papers 6531
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#2P. L. Tikhomirov (MSU: Moscow State University)H-Index: 9
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Zircons from volcanic and plutonic rocks of Nembonda volcanic field (the part of Anadyr segment of the Okhotsk-Chukotka volcanic belt) yield the following SHRIMP U-Pb ages, Ma: 147,7 ± 2; 123,8 ± 1,7; 119,3 ± 1,7; 9,8 ± 0,5; 80,55 ± 0,96. These results confirm the hypothesis about the significant Aptian magmatic event in Verkhoyansk-Chukotka tectonic province, and give rise to the revision of the boundaries of the Okhotsk-Chukotka belt.
#1I. Yu. Badanina (RAS: Russian Academy of Sciences)H-Index: 6
#2Elena Belousova (Macquarie University)H-Index: 26
Last.Sergey F. Sluzhenikin (RAS: Russian Academy of Sciences)H-Index: 2
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This study presents the first results of oxygen isotope analyses (δ 18 O) collected on zircons from the Talnakh economic intrusion within the Noril’sk province. Zircons from gabbro-diorite, gabbroic rocks of the layered series and plagioclase-bearing wehrlite have similar mantle-like mean δ 18 O values (5,39 ± 0,49‰; 5,64 ± 0,48‰ and of 5,28 ± 0,34‰, respectively), which differ from δ 18 O in zircons from sulfide-bearing melanocratic troctolite with a taxitic texture in the lower part of the int...
#1G. A. Petrov (RAS: Russian Academy of Sciences)H-Index: 7
#2N. I. TristanH-Index: 3
Last.A. V. Maslov (RAS: Russian Academy of Sciences)H-Index: 14
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For the first time, the time of completion of the formation of calc-alkaline volcanic complexes of the Devonian Island Arc (Franian) in the Northern Urals was determined. It is shown that the late Devonian volcanic rocks of the Limka series have geochemical characteristics that bring them closer to the rocks of developed island arcs and active continental margins. The detected delay of the final episode of calc-alkaline volcanism in the Northern Urals in comparison with the similar event in the ...
#1N. A. Kanygina (RAS: Russian Academy of Sciences)H-Index: 2
#2A. A. Tretyakov (RAS: Russian Academy of Sciences)H-Index: 11
Last.J. V. Plotkina (RAS: Russian Academy of Sciences)
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U–Pb geochronological studies of detrital zircons from quartzite–schist sequences of the Akbastau Formation of the Chu Block (northwestern part of the Chu–Kendyktas terrane, Southern Kazakhstan) have been provided. The concordant ages of detrital zircons are predominantly within the intervals of 1672–2115 Ma with peaks at 1697, 1780, 1857, and 2066 Ma. Individual zircon grains display ages of 2291–2332 Ma with peaks at 2303 and 2322 Ma. Neoarchean ages of 2608–2747 Ma with a peak at 2681 Ma char...
#1A. G. Fatyanov (RAS: Russian Academy of Sciences)H-Index: 1
#2V. Yu. Burmin (RAS: Russian Academy of Sciences)H-Index: 3
It is generally accepted that PKP precursor waves arriving ahead of PKP-waves observed in real data are explained by scattering on small-scale inhomogeneities in the lower mantle. In this paper, a stable analytical solution (without interference) was obtained for the field of longitudinal waves in a layered (discrete) ball of planetary size. The calculations of the total wave field, rays, and travel-time curves of longitudinal waves for the spherical model of the Earth AK135 with a carrier frequ...
#1A. L. Sobisevich (RAS: Russian Academy of Sciences)H-Index: 7
#2R. A. Zhostkov (RAS: Russian Academy of Sciences)H-Index: 1
A numerical parametric study of the scattering features of Rayleigh waves that appear during the operation of a vibroseismic source on near-surface inhomogeneities (seismic barriers) is performed. To find new approaches to the problem of global sounding of the Earth with powerful vibroseismic sources, the conditions for increasing the efficiency of emission of bulk waves due to the design features of seismic barriers are analyzed.
#1D. P. Krylov (RAS: Russian Academy of Sciences)H-Index: 3
#2A. B. Kuznetsov (RAS: Russian Academy of Sciences)H-Index: 19
Temperature relations of β-factors for 18O/16O fractionations in TiO2 polymorphs have been determined using the density functional theory: 1000 ln βrt(18O/16O) = 6.93039x – 0.08158x2 + 0.00116x3 + 0.08305*P 1000 ln βant(18O/16O) = 7.34275x – 0.09906x2 + 0.00153x3 + 0.08027*P 1000 ln βbrk(18O/16O) = 7.19088x – 0.09157x2 + 0.00139x3 + 0.07601*P, x = 106/T(K)2, P is pressure (GPa). The deduced relations can be applied for isotope thermometry if combined with β-factors of coexisting phases.
#1E. I. Ryzhak (RAS: Russian Academy of Sciences)
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Stability of stratified elastic geosystems in a gravity field is studied analytically with regard for the shear stiffness of geomaterial. A sufficient condition for stability of a geomass clamped at the lateral boundaries, is obtained: for any ratios of dimensions of the geomass it is sufficient for stability that the rate of density increase with depth (in the loaded equilibrium state) exceed a certain positive value which depends on shear stiffness so that the greater the stiffness, the less t...
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