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The paper reports on the deep geophysical studies performed by the Geological Survey of Russia (VSEGEI) under the international project – Deep Processes and Metallogeny of Northern, Central and Eastern Asia. A model of the deep crustal structure is represented by a set of crustal thickness maps and a 5400-km long geotransect across the major tectonic areas of Northeastern Eurasia. An area of 50000000 km2 is digitally mapped in the uniform projection. The maps show the Moho depths, thicknesses of the main crustal units (i.e. the sedimentary cover and the consolidated crust), anomalous gravity and magnetic fields (in a schematic zoning map of the study area), and types of the crust. The geotransect gives the vertical section of the crust and upper mantle at the passive margin of the Eurasian continent (including submarine uplifts and shelf areas of the Arctic Ocean) and the active eastern continental margin, as well as an area of the Pacific plate.

Over a period of the past 15–20 years, the Russian Government implemented the Arctic Mega Project for geological and comprehensive study of the Arctic Ocean. In this paper we discuss the methods that were used in the implementation of this project. In the course of several expeditions, multiple types of data were acquired, which included: (1) seismic data of different types, (2) subbottom profiler data, (3) geological sampling on slopes of the Mendeleev Rise with the use of special equipment, (4) borehole drilling, (5) gravity and magnetic anomalies, (6) offshore geodetic data, (7) multi-beam bathymetry surveys, and (8) field surveys on multiple Arctic islands. Several nuclear icebreakers and a scientific research submarine were deployed in these operations. Specifically, more than 23,000 km of 2D multi-channel seismic lines and more than 4000 km of wide-angle refraction/reflection seismic lines were acquired, in addition to subbottom profiles for the Eurasia Basin and new bathymetric data of the Arctic Ocean. The new database is intended to facilitate the development of new insights into Arctic geology and geodynamics and contribute to a better understanding of the structure and tectonic evolution of the Arctic Ocean as a whole.

The Circum-Arctic terrains comprise series of complex geological structures, with fragments of Archaean to Paleoproterozoic shields and platforms, remains of orogenic belts of Neo-proterozoic to Cenozoic ages, Paleozoic and Mesozoic platforms and sedimentary basins, large igneous provinces, and Mesozoic-Cenozoic rift structures and basin fill in the northern North Atlantic and Central Arctic Ocean. Major orogenic events include the Neoproterozoic Timian Orogeny, the Mid Paleozoic Caledonian and Eurekean orogenies, the Late Paleozoic to Early Mesozoic Ellesmerian and Uralian orogenies, and the Late Mesozoic to Cenozoic Eurekan orogeny. The breakup of Arctida-II in the Mesozoic and Cenozoic, and the Cenozoic sea-floor spreading in the North Atlantic and Polar Ocean, led to significant redistribution of land masses and to the formation of the present Arctic Ocean shelves and basins. The central Arctic Ocean remains one of the more debated areas in terms of plate tectonic evolution. Most models include spreading in the Canada Basin (southern Amerasia Basin) at ca. 125–80 Ma, the Makarov-Podvodnikov Basin (northern Amerasia Basin) at around 80–60 Ma, and the Eurasia Basin at ca. 55-0 Ma. Different crustal and tectonic models for the Amerasia and Eurasia basins and their margins are discussed, and present knowledge of the basin fill histories briefly reviewed. The present paper serves as an introduction to the current Special Issue on the Geodynamics of the Arctic.

Fossiliferous carbonate rocks dredged during the “Arctic-2012” cruise on the Mendeleev Rise (eastern Arctic) provide proof of the presence of Upper Silurian(?)–Middle Devonian, Famennian–Tournaisian, Bashkirian–Kasimovian, Gshelian–lower Asselian(?) and Kungurian–Kazanian carbonate deposits. The wide spectrum of facies includes deposits of both photic zone (with fusulinids, algae, relicts of microbial and coral reefs) and deeper dysphotic areas (with trilobites, deep-water tentaculitids and ostracods). The results obtained suggest that there were at least three periods of carbonate platform sedimentation during the latest Silurian(?) to Permian. The Late Silurian?–Devonian biota do not show biogeographical differentiation, but rather are distributed globally. Shallow-water foraminifera and some algae of early Pennsylvanian–basal Cisuralian age belong to the warm-water province. These forms are unknown in the Moscovian–Permian of the Boreal Realm (Taimyr, New Siberian Islands, Verkhoyanie, Omolon Massif) but are typical for Alaska and Arctic Canada, Wrangel Island, Chukotka, Polar Urals and Svalbard. The disappearance of warm-water biota during late Artinskian-Kungurian times led to a subsequent predominance of smaller foraminifera: this assemblage with Protonodosaria is widely distributed in Permian deposits of Novaya Zemlya, Urals, Barents Sea and the eastern Arctic. The warm-water Bashkirian-Asselian biota suggests that the Mendeleev-Chukotka-Wrangel block was a low-latitude shallow basin with predominant carbonate sedimentation, being part of the Arctida supercontinent, connected temporarily with the eastern margin of Laurasia (Chukcha-Alaska block).

The results of local U–Th–Pb-SIMS-SHRIMP-II analysis of the collection of pyrochlores from Nb rare-metal deposits of the Ilmeny–Vishnevogorsky alkaline complex are discussed. Independently of the chemical composition, the host rocks, and the stage of carbonatite formation, the studied pyrochlores are characterized by an almost undisturbed U–Pb isotope system. This allowed to estimate the age of ore mineralization on three deposits (Vishnevogorsky, Buldymsky, and Potaninsky) with an accuracy of ±1–6 m. y. The U–Pb system of the studied pyrochlore samples suggests three epochs of the mineral formation: 380, 230–240, and 216–218 Ma. Convergence of the results obtained by the different methods of U–Pb dating for one of the samples from our collection (±0.5–1.0 Ma) allows to use it as an in-house standard for local dating.

Deep seismic studies of the Sea of Okhotsk region started in late 1950s. Since that time, wide-angle reflection and refraction data on more than two dozen profiles were acquired. Only five of those profiles either crossed or entered the deep-water area of the South-Okhotsk Basin (also known as the Kuril Basin or the South-Okhotsk Deep-Water Trough). Only P-waves were used to develop velocity-interface models in all the early research. Thus, all seismic and geodynamic models of the Okhotsk region were based only on the information on compressional waves. Nevertheless, the use of Vp/Vs ratio in addition to P-wave velocity allows discriminating felsic and mafic crustal layers with similar Vp values. In 2007 the Russian seismic service company Sevmorgeo acquired multi-component data with ocean bottom seismometers (OBS) along the 1700-km-long north-south 2-DV-M Profile. Only P-wave information was used previously to develop models for the entire profile. In this study, a multi-wave processing, analysis, and interpretation of the OBS data are presented for the 550-km-long southern segment of this Profile that crosses the deep-water South-Okhotsk Basin. Within this segment 50 seismometers were deployed with nominal OBS station spacing of 10–12 km. Shot point spacing was 250 m. Not only primary P-waves and S-waves but also multiples and P-S, S-P converted waves were analyzed in this study to constrain velocity-interface models by means of travel time forward modeling. In offshore deep seismic studies, thick water layer hinders an estimation of velocities in the sedimentary cover and in the upper consolidated crust. Primarily, this is due to the fact that refracted waves propagating in low-velocity solid upper layers interfere with high-amplitude direct water wave. However, in multi-component measurements with ocean bottom seismometers, it is possible to use converted and multiple waves for velocity estimations in these layers. Consequently, one can obtain P- and S-waves velocity models of the sedimentary strata and the upper consolidated crust. Velocity values in the upper consolidated crust beneath the South-Okhotsk Basin (Vp = 5.50–5.80 km/s, Vp/Vs = 1.74–1.76) allow interpretation of this 2.5–3.5-km-thick layer to be consistent with a felsic (granodioritic) crust. These results suggest that the Earth's crust in this region can be considered continental in nature, rather than previously accepted oceanic crust. Even though, the crust is thinned and stretched at this location.

The influence of the size of conjugated π-system on catalytic activity of cobalt complex with β-octaphenylporphyrin and its tetraaza-, tetrabenzo and tetrabenzotetraaza derivatives was studied in present work. It is found that catalytic activity for oxidation of sulfur-containing compounds increases under extension of conjugated macrocycle system according to the following series CoP < CoBP ≤ CoPz < CoPPz ≪ CoPc.

We present a new model of the crustal and tectonic structure of the Arctic region north of 60° N latitude, constrained as a part of the international Atlas of Geological Maps of the Circumpolar Arctic under the aegis of the Commission for the Geological Map of the World. The region is largely formed by (i) Archean–Paleoproterozoic shields and platforms, (ii) orogenic belts of the Neoproterozoic to the Late Mesozoic ages overlain by platform and basin sediments, (iii) Cenozoic rift structures formed in part as a consequence of seafloor spreading in the North East Atlantic Ocean with propagation into the Central Arctic Ocean along the Gakkel Ridge, (iv) deep-water ocean basins and shallow-water shelves of the North Atlantic and Arctic Oceans, and (v) associated large igneous provinces (LIPs). We present a series of maps for the Circumpolar Arctic which include maps of the depth to Moho and thickness of the sedimentary cover and presents tectonic regionalization based on 18 major crustal types (oceanic, transitional, and continental) recognized in the Arctic. A 7600 km-long crustal geotransect across the region illustrates the details of its crustal and tectonic structure. We discuss geological, geophysical and geochemical datasets on which the new regional model is based. These include magnetic and gravity maps of the Circumpolar Arctic and a wide range of existing and recently acquired bathymetric, geophysical (including seismic), geological, isotope and geochronological data (illustrated by new age data for seabed and bedrock samples from the New Siberian Islands). The analysis of these data in the framework of regional tectonic evolution allows for correlating onshore and offshore lithospheric fragments and for recognizing regions with oceanic, transitional, and continental crust in the Circumpolar Arctic.

We present a seismic and density model for the crust and the uppermost mantle of the Arctic Ocean off-shore Chukotka down to a 40 km depth along a 740-km long latitudinal (at ca. 77°N) “Arctic-2012” wide-angle/MCS profile. Joint seismic and gravity modeling indicates significant differences in the crustal velocity and density structure of the northeastern Vilkitsky Trough, the Mendeleev Rise, the Chukchi Basin, and the Chukchi Plateau. The Vilkitsky Trough and the Chukchi Basin have a thin crust (23 km and 18 km, correspondingly), 6–8 km thick sedimentary cover, 3–6 km thick upper/middle crust (with the smallest thickness of 3–4 km beneath the Chukchi Basin), and 9–10 km thick lower crust. The uppermost mantle of the Chukchi Basin has a high density (3.27–3.31 g/cm3) and a low velocity (Vp ∼ 7.8 km/s), which we explain by 5–10% serpentinization of mantle peridotite at a 22–35 km depth as a result of crustal hyperextension and seawater penetration. The Chukchi Plateau and the Mendeleev Rise have a thick crust (28–29 km and 33–34 km, correspondingly), underlain by a normal mantle (Vp ∼ 8.0 km/s). The Chukchi Plateau has a 2‐4 km thick sedimentary cover, a thick (15–18 km) upper/middle crust with low-Vp, low-density lenses interpreted as magmatic intrusions, and a 9–12 km thick lower crust. The Mendeleev Rise has a 3–7 km thick sedimentary cover (most of which is formed by metasediments with a possible presence of volcanic rocks), a 7–8 km thick upper/middle crust, and a thick (20 km) lower crust which includes a 3–4 km thick high-velocity (Vp ∼ 7.3 km/s) underplated magmatic material. The high density anomaly (at depths >35 km) below the Mendeleev Rise is interpreted as an eclogitic body in the upper mantle lithosphere. Seismic Vp and Vp/Vs structure of the crust along the “Arctic-2012” profile indicates its continental nature: a 3–18 km thick upper/middle crustal layer with Vp ∼ 6.0–6.8 km/s and Vp/Vs ∼ 1.70–1.73 typical of felsic-intermediate continental upper crust is present along the entire profile. Strong variability of the crustal structure along the profile reflects its significant modification by metamorphism and magmatism, possibly related to the High-Arctic Large Igneous Province and localized lithosphere extension beneath the Chukchi Basin.

Mathematical kinematic model of a wheeled robot, operating according to the algorithm to achieve the specified coordinates was developed. Model was designed in visual programming platform LabView. The problem of control of autonomous mobile wheeled robot moving in two dimensions without obstacles was considered. Applicability of this model to the real problems of motor control and drive wheel robots was analyzed and future research directions was defined. The efficiency and effectiveness of the algorithm described was illustrated in the graphs of the mathematical model of the robot.