New geological and paleontological data on Alba Guyot (Magellan Seamounts, Pacific Ocean)

New materials obtained in the Pacific during cruises of the R/V Gelendzhik carried out by the State Scientific Center Yuzhmorgeologiya in 2000–2001 make it possible to specify the geologic and geomorphologic structure of Alba Guyot and clarify lithological and paleontological characteristics of lithotectonic rock complexes ranging from the Early Cretaceous to Pleistocene in age. Based on macro-and microfossils from sedimentary rocks several “transgressive” phases are distinguished in the guyot development: Cenomanian-Turonian, late Campanian-Maastrichtian, late Paleocene-middle Eocene, and Late Cenozoic. Finds of Paleogene molluscan and coral remains, together with planktonic foraminifers, imply relatively shallow sedimentation settings on Alba Guyot during the early Paleocene.     

Recent crustal movements and the Moneron earthquake of 1971

From the results of high-precision levelling conducted in the southern part of Sakhalin Island, the dynamics of the earth's surface have been determined before the Moneron earthquake in 1971, during its numerous aftershocks and in the following periods. Great subsidence, of up to 7–8 cm, preceded the earthquake, then a 3-year period of steady state followed and at the end of this period the earthquake happened. After this event vertical movements show an inherited character related to the very recent geological structures. Horizontal displacements of the triangulation net, 50 km distant from the earthquake epicentre, were also noted; they had a northeast direction and an amplitude of 7 cm.     

Electrodynamic coupling between ionospheric convection patterns in the northern and southern hemispheres

A numerical model of the high-latitude ionospheric electric field is presented. To perform the calculations, a model of the field-aligned current source is proposed. The electric field patterns are calculated consistently both in the northern and southern hemispheres. Effects of season, universal time, solar and geomagnetic activity, the neutral atmosphere winds, and of the IMF sector structure are considered. In particular, dynamics of the parameters of convection cells are investigated that depend on the action of these factors. Comparison of the results with experimental data is carried out.     

GPS–TEC response to the substorm onset during April 5, 2010, magnetic storm

We consider disturbances of total electron content (TEC) of the high-latitude ionosphere provided by the GPS global navigation satellite system before and during the magnetic storm on April 5, 2010. Simultaneously, we examine magnetic data from all available magnetometer arrays in the northern hemisphere, augmented with data from scanning photometers and riometers. The substorm onset, during both non-storm and storm periods, is found to cause significant enhancement of TEC scintillations characterized by the TEC time derivative dTEC. Comparison of 2D maps of the spectral power of magnetic fluctuations in the Pc5 band (1–10 mHz) and dTEC during substorms shows a good spatial and temporal correspondence between them. Both magnetic and ionospheric fluctuations tend to concentrate inside the auroral oval, the boundaries of which are determined from the OVATION model. The time–space evolution of TEC scintillations is rather similar to that of ultra-low-frequency magnetic fluctuations, but not to that of the ionospheric electrojet. GPS signal phase slips, resulting in non-physical TEC jumps (>1 TECu/min), occur predominantly inside the auroral oval and in the vicinity of its equatorward boundary.     

Fine spatial structure of the North Atlantic current's western boundary

The results of an analysis of the distribution of the thermohaline characteristics in the frontal zone of the North Atlantic current area near 46°00' N are reported, the spatial resolution being 2–2.5 miles. Minor structural features of the frontal zone have been observed, characterized by the occurrence of intrusions of diverse origin. The intrusive fine structure was found to be inherent only to the near-frontal area and is incapable of penetrating through the boundary of the current's main jet.Translated by Vladimir A. Puchkin.     

Deep-Water Glacial Plow Marks in the Western Margin of the Barents Sea

Doklady Earth Sciences - Data obtained from high-resolution multibeam echo sounding during the 26th cruise of R/V Akademik Nikolai Strakhov, maps of the Western Arctic bathymetry, the...     

Studying the Experience of Solving Water Supply Problems in the Medieval Crimea (Sudak XIV–XV Centuries)

Water Resources - Archeological and geological data on solving the problems of water supply and water use in the medieval Sougdeia (Sudak Town in the XIV–XV centuries) are generalized and...