Determination of design hydrological characteristics with consideration of historical maxima

Application of information about the historical maxima in hydrological computations allows one to improve design hydrological performances and to pass in some cases from extrapolation to interpolation as a more reliable solution. In this paper, an analytical solution is given for a task of determination of empirical probabilities and parameters of distribution function taking into account any historical maxima, which are located inside as well as outside the time series of observations and for their mixed location. For particular case studies, an advantage of consideration of the historical maxima is shown in comparison with computations without these maxima. It has also been shown that the exponential function between maximum discharges in order of their reduction and ordinates of standard normal distribution are effective enough for fitting the upper part of empirical distribution function.     

Middle Devonian Paleomagnetism of Geological Complexes of Central Tuva

New paleomagnetic data are obtained for Middle Devonian rocks of Central Tuva. The rocks contain one-, two-, or three-component magnetization. The low-temperature (LT) components of magnetization are close to the directions of the present-day or Cenozoic magnetic field in Tuva. Based on the directions of the high-temperature (HT) components of magnetization, which were distinguished in the magnetite spectrum of blocking temperatures of up to 580оС, we revealed a prefolding magnetization of different polarity. The time when Middle Devonian rocks acquired the prefolding HT component of magnetization almost does not differ from the time of rock formation. Middle Devonian sequences were formed at low latitudes (19°–25° N). We calculated the Middle Devonian paleomagnetic pole (Φ =–13°, Λ = 106°, A₉₅ = 7), which can be used to describe the movement of the Caledonian block in Central Asia, and probably Siberia, if these blocks had been tectonically coupled by the Devonian.     

Submesoscale eddies in Peter the Great Bay of the Japan/East Sea in winter

Ocean Dynamics - Cold-core (T < 0 °C) domes of dense water σθ > 27.24 kg/m3 were observed in the near-bottom layer at the...     

The Mg-carbonate-Fe interaction:Implication for the fate of subducted carbonates and formation of diamond in the lower mantle

The fate of subducted carbonates in the lower mantle and at the core-mantle boundary was modelled via experiments in the MgCO3-Fe^0 system at 70-150 GPa and 800-2600 Kin a laser-heated diamond anvil cell.Using in situ synchrotro n X-ray diffraction and ex situ transmission electron microscopy we show that the reduction of Mg-carbonate can be exemplified by:6 MgCO3+19 Fe=8 FeO+10(Mg0.6Fe^0.4)O+Fe7 C3+3 C.The presented results suggest that the interaction of carbonates with Fe^0 or Fe^0-bearing rocks can produce Fe-carbide and diamond,which can accumulate in the D"region,depending on its carbon to Fe ratio.Due to the sluggish kinetics of the transformation,diamond can remain metastable at the core-mantle boundary(CMB)unless it is in a direct contact with Fe-metal.In addition,it can be remobilized by redox melting accompanying the generation of mantle plumes.     

Features of the propagation of pseudorandom pulse signals from the shelf to deep water in the presence of gyre formation on the acoustic track

Doklady Earth Sciences - The paper discusses the results of an experiment conducted in the Sea of Japan in March 2016 on an acoustic track 194 km long in winter hydrological conditions. The most...     

Placer diamond potential of the siberian craton: possible sources and ages

Many diamond placers in the Siberian craton are heterogeneous consisting of several components that differ in origin and ages of the source. The diamonds are either kimberlite-hosted or are exotic varieties which occur mostly in the northeastern craton periphery and come from primary deposits of unknown types and ages. The two groups of diamond placers in the area represent two evolution trends: those found in Middle Paleozoic kimberlites originated in the Famennian and the exotic diamond groups became involved in sedimentation in the Carnian. The trends have been associated with successive weathering of older diamond hosts and redeposition of the minerals into younger sediments. Having joined since the Late Triassic, the two trends eventually produced a polygenetic and multistage mixture of diamond groups in placers.     

Hydrochemical Study of Academy Bay (Sea of Okhotsk)

Oceanology - The hydrological and hydrochemical data of surface and bottom waters of Academy Bay were obtained on two POI FEB RAS cruises carried out from July 11 to 14, 2016 and from September 15...     

Integral Deep Models of the Pechenga and Onega Ore Regions

A new interpretation of the geological and seismic data demonstratd a correlation between the surface structures of endogenic ore regions of the Baltic Shield, the Moho surface relief, and local heterogeneities in the Earth’s crust. As a result, based on consistent analysis of the geological and seismic data, models of the deep structure of the Pechenga and Onega ore regions were constructed and compared.     

Composition of Fluids Responsible for Gold Mineralization in the Pechenga Structure of the Pechenga–Imandra–Varzuga Greenstone Belt,Kola Peninsula,Russia

This study presents the first fluid inclusion data from quartz of albite–carbonate–quartz altered rocks and metasomatic quartzite hosting gold mineralization in the Pechenga structure of the Pechenga–Imandra–Varzuga greenstone belt. A temperature of 275–370°C, pressure of 1.2–4.5 kbar, and the fluid composition of gold-bearing fluid are estimated by microthermometry, Raman spectroscopy, and LA-ICP-MS of individual fluid inclusions, as well as by bulk chemical analyses of fluid inclusions. In particular, the Au and Ag concentrations have been determined in fluid inclusions. It is shown that albite–carbonate–quartz altered rocks and metasomatic quartzite interacted with fluids of similar chemical composition but under different physicochemical conditions. It is concluded that the gold-bearing fluid in the Pechenga structure is similar to that of orogenic gold deposits.