The 1.80–1.74-Ga gabbro–anorthosite–rapakivi Korosten Pluton in the Ukrainian Shield: a 3-D geophysical reconstruction of deep structure

The deep structure of the gabbro–anorthosite–rapakivi granite (“AMCG-type”) Korosten Pluton (KP) in the northwestern Ukrainian Shield was studied by 3-D modelling of the gravity and magnetic fields together with previous seismic data. The KP occupies an area of ca. 12,500 km² and comprises several layered gabbro-anorthositic intrusions enveloped by large volumes of rapakivi-type granitoids. Between 1.80 and 1.74 Ga, the emplacement of mafic and associated granitoid melts took place in several pulses. The 3-D geophysical reconstruction included: (a) modelling of the density distribution in the crust using the observed Bouguer anomaly field constrained by seismic data on Moho depth, and (b) modelling of the magnetic anomaly field in order to outline rock domains of various magnetisation, size and shape in the upper and lower crust. The density modelling was referred to three depth levels of 0 to 5, 5 to 18, and 18 km to Moho, respectively. The 3-D reconstruction demonstrates close links between the subsurface geology of the KP and the structure of the lower crust. The existence of a non-magnetic body with anomalously high seismic velocity and density is documented. Most plausibly, it represents a gabbroic stock (a parent magma chamber) with a vertical extent of ca. 20 km, penetrating the entire lower crust. This stock has a half-cylindrical shape and a diameter of ca. 90 km. It appears to be connected with a crust–mantle transitional lens previously discovered by EUROBRIDGE seismic profiling. The position of the stock relative to the subsurface outlines of the KP is somewhat asymmetric. This may be due to a connection between the magmatism and sets of opposite-dipping faults initially developed during late Palaeoproterozoic collisional deformation in the Sarmatian crustal segment. Continuing movements and disturbances of the upper mantle and the lower crust during post-collisional tectonic events between 1.80 and 1.74 Ga may account for the long-lived, recurrent AMCG magmatism.     

Hydraulic modeling of flood pulses in the Middle Bussento Karst System (MBSKS), UNESCO Cilento Global Geopark,southern Italy

Karst systems provide water for domestic and industrial uses and for generating hydropower, but they can also create fluvial hazards, such as upstream back‐flooding and downstream karst flash‐flood events. However, these hazards are difficult to foresee due to the complex recharge‐discharge processes as well as the lack of information on the inside of the system, which has often not been completely surveyed by speleologists or explored by boreholes. To overcome these difficulties, hydro‐chemical data from the monitoring system in the Middle Bussento Karst System (MBSKS), one of the first Experimental Karst Systems in southern Italy, were recorded and previously discussed. Based on shared background in flood karst hydraulic modeling, this paper describes the conceptual premises and rationale of a general‐purpose hydraulic model that is suitable both for the MBSKS and for other Mediterranean, multi‐recharge, mature, conduit‐dominated karst systems. To test the reliability of the model, simulations of time–space behavior and response are performed using natural and artificial flood pulses “as tracers”, considering a “pulse” as a significant variation in water quantity and/or quality. The results of the model explain the interactions between allogenic, autogenic, and anthropogenic recharges from differentiated sources and phreatic conduit systems. These results also clarify the overall response of karst springs at typical time scales of flood pulses. Table acronym name     

Steady-state double layer structures in the interstellar medium

A one-dimensional, self consistent theoretical model is constructed for double layers in a thermodynamically nonequilibrium astrophysical plasma. A steady state is maintained by an asymmetry in the fluxes from both sides. The range of possible values of the parameters is determined.     

Geodetic Rotation of Neptune’s Satellites

Solar System Research - The paper considers the most significant relativistic effects in the rotational dynamics of Neptune’s satellites (Triton (N1), Naiad (N3), Thalassa (N4), Despina (N5),...     

Construction of the semi-analytical and numerical solutions to the problem of rotational motion of the moon

New high-precision, semianalytical and numerical solutions to the problem of the rotational motion of the Moon are obtained, for use in the long 418.9-year time frame. The dynamics of the rotational motion of the Moon is studied numerically using the Rodrigues-Hamilton parameters, relative to the fixed ecliptic for the epoch J2000. The results of the numerical solution to the problem under study are compared with a compiled semianalytical theory of Moon rotation (SMR). The initial conditions for the numerical integration have been taken from the SMR. The comparative discrepancies derived from the comparison between the numerical solutions and the SMR do not exceed 1.5″ on the time-scale of 418.9 yr. The investigation of the comparative discrepancies between the numerical and semianalytical solutions is performed using the least squares and spectral analysis methods in the Newtonian case. All the periodic terms describing the behavior of the comparative discrepancies are interpreted as the corrections to the semianalytical SMR theory. As a result, the series are constructed to describe the rotation of the Moon (MRS2010) in the time interval under study. The numerical solution for the Moon’s rotation has been obtained anew, with new initial conditions calculated using MRS2010. The discrepancies between the new numerical solution and MRS2010 do not exceed 20 arc milliseconds on the time-scale of 418.9 years. The results of the comparison suggest that that the MRS2010 series describe the rotation of the Moon more correctly than the SMR series.     

Determination of Trace Elements (Ag, B, Ge, Mo, Sn, W, Tl) in Reference Samples of Soils and Bottom Sediments by Atomic Emission Spectrometry: A Traceability and Fitness-for-Purpose Study

Reference samples of soils from the Institute of Applied Physics, Irkutsk (RIAP), the Institute of Geochemistry, Irkutsk (IGI) and the United States Geological Survey, Reston (USGS) were analysed with the aim of determining Ag, B, Ge, Mo, Sn, Tl and W abundances by an atomic emission method with air-stabilised D.C. arc excitation. Two series of reference samples of soils and bottom sediments, GSS-1-8 and GSD-1-12 (IGGE), were used to ensure the traceability link for the analytical results. Traceability was also demonstrated through the comparison of measured results by AES and ICP-MS methods. It is shown that the reference samples GSS-1-8 and GSD-1-12 satisfied the "fitness-for-purpose" criterion (uncertainty U of the certified value should be one-third to one-tenth the magnitude of routine laboratory data uncertainty S (S/U > 3-10)) and can be applied for calibrating AES techniques.     

The Crati Submarine Fan, Ionian Sea

The Crati Fan is located in the tectonically active submerged extension of the Apennines chain and foretrough. The small fan system is growing in a relatively shallow (200 to 450 m), elongate nearshore basin receiving abundant input from the Crati River. The fan is characterized by a short, steep, channelized section (inner or upper fan) and a smooth, slightly bulging distal section (outer or lower fan). The numerous subparallel channels head in the shelf or littoral zone and do not form branching distributary patterns. Sand and mud depositional lobes of the outer fan stretch over more than 60% of fan length. Margin setting represents fan and/or source area     

Methods for reconstructing harmonic functions from the magnetic field ΔT and V.N. Strakhov’s function ΔS: A review

We give an overview of the methods designed for reconstructing close-to-harmonic functions from the magnetic field ΔT. The formula of Yu.P. Tafeev is refined. It is shown that this refined formula directly leads to the relation derived by V.M. Gordin and his colleagues that allows isolating the harmonic component in the function ΔT. V.N. Strakhov’s linearized representation of the function ΔT is immediately derived from the main approximate Tafeev formula for Q ΔT. The experience of using Strakhov’s ΔS function in the interpretation of the magnetic anomaly ΔT generated by the Krivoi Rog structure is described. It is noted that the problem of reconstructing the corresponding harmonic functions from the data of magnetic and gravity surveys has much in common. The specific features of measuring the magnetic field H and magnetic induction B in the material media are considered, and the physical interpretation of these fields is presented.     

Consideration of Relativistic Effects in the Rotation of Mars and its Satellites

Solar System Research - This study is dedicated to the consideration of the relativistic effects (geodetic precession and nutation that make up the geodetic rotation) in the rotation of Mars and...