Natural bitumen fields in the northeast of the Siberian Platform (Russian Arctic sector)

In the northern and northeastern Siberian Platform, within the Anabar and Olenek zones, there are a number of hypergene bitumen accumulations (fields) and natural bitumen seeps, whose total resources are estimated at >5 bln tons. Bitumen fields are confined to a wide stratigraphic range from Precambrian to Mesozoic. A detailed geochemical study was performed for bitumens of the largest Olenek field, whose naphthides are localized mainly in Permian sandstones of deltaic and coast-marine genesis. Chromato-mass spectrometric analysis showed that normal alkanes are drastically reduced in the saturated fraction of the bitumens and most of terpanes are a homologous series of 25-norhopanes, which evidences the intense bacterial degradation of hydrocarbon pools. Identification of bicyclic sesquiterpenes, tetracyclic onocerane, and other biomarkers testifies that the organic matter of source rocks was rich in higher-plants remains. The concentrations of steranes are low, whereas those of earlier unknown 8-14-secosteranes are rather high. The set of geochemical data on the Permian bitumens of the Olenek field, including the isotopic characteristics of carbon (δ¹³C of ?25.8 to ?31.3‰), suggests that the coeval oil source rocks on the passive continental margin (at the place of the present-day Verkhoyansk fold belt) were the main source of hydrocarbons for the field. Assessment of oil and gas resources, including giant bitumen pools, and their exploration in the framework of “The fundamentals of Russian state policy in Arctic up to 2020” have become a top-priority problem. Petroleum refining products might be economically feasible raw materials in the eastern Russian Arctic sector to be supplied via the Northern Sea Route.     

Metacarbonate Rocks (Calciphyres) of the Lapland—Kolvitsa Granulite Belt, Baltic Shield

Geological, petrochemical, and geochemical data are presented on metacarbonate rocks (calciphyres) of the Lapland—Kolvitsa granulite belt, Baltic Shield. The normative mineral composition of source rocks of the studied calciphyres was first reconstructed. High contents of some indicator elements (Fe, Mn, Cr, Co, P, Pb, and others) suggest that material supplied to the paleobasin was derived from diverse rocks (ultramafic, mafic, intermediate, and felsic). Contents and correlations of some trace elements (Sr, Li, F, Ba, and others) indicate that primary sediments formed under humid-semihumid paleoclimate in a fresh-water paleobasin (lagoon) characterized by occasional increase in salinity.     

Metasedimentary Rocks of the Lapland–Kolvitsa Granulite Belt of the Baltic Shield: Primary Mineral Composition and Petrogeochemistry

The normative mineral composition is reported on source rocks of metasediments from the granulite belt of the Baltic Shield. The primary composition, CIA index, and position of data points of studied rocks in discriminant diagrams indicate that a significant part of the studied rocks formed from immature sediments (graywackes and subgraywackes). The material supplied to sedimentation paleobasins was obtained from different (ultrabasic, basic, intermediate, and acid) rocks. The paleobasin was characterized by organic activity and reducing environment in the bottom layer. Correlation found between some elements, e.g., (Rb, Ba, Pb)–K; Sr–(Na, Ca), and so on, is also typical of Phanerozoic deposits. The possible contents of OM (C_org) and U were reconstructed in source rocks of metasediments of the Lapland–Kolvitsa granulite belt of the Baltic Shield.     

Upward high-energy field-aligned electron beams above the polar edge of auroral oval: observations from the SKA-3 instruments onboard the Auroral Probe (Interball-2)

A new phenomenon was found at the polar edge of the auroral oval in the postmidnight-morning sectors: field-aligned (FA) high-energy upward electron beams in the energy range 20–40 keV at altitudes about 3 R_E, accompanied by bidirectional electron FA beams of keV energy. The beam intensity often reaches more than 0.5 · 10³ electrons/s · sr · keV · cm², and the beams are observed for a relatively long time (3 10²–10³ s), when the satellite at the apogee moves slowly in the ILAT-MLT frame. A qualitative scenario of the acceleration mechanism is proposed, according to which the satellite is within a region of bidirectional acceleration where a stochastic FA acceleration is accomplished by waves with fluctuating FA electric field components in both directions.     

The heating of the earth during its formation

The thermal state of the Earth accumulating from solid bodies is investigated. The conductivity equation is deduced for a growing spherically symmetrical planet which takes into account heating by impacts of bodies, by radioactivity, and by compression of its material. The cooling is produced mainly by impact mixing, which is approximated by extrapolating the parameters from known impact craters to larger sizes. The solution of a more simple conductivity equation for a uniformly heated plane parallel layer with moving boundaries is found. It can be considered as an approximate quasi-stationary solution for the temperature distribution in the outer parts of the growing Earth. The result depends substantially on the sizes of impacting bodies but almost not at all on the time scale of the accumulation. The latter only weakly affects the surface temperature and does not affect the temperature distribution in the layer. For bodies of small radii, r′ < r₁, where the size of the crater is not affected appreciably by gravitation (for the present mass of the Earth r₁ ≈ 1 km), the heating is small. For bodies with r′ > r₁, the heating of the layer is roughly proportional to the ratio $\text{r′}\text{r}{}_1$. Toward the end of the Earth's accumulation the melting point can be reached in the outer layer at r′_M ? 60 km, where r′_M is the radius of the largest body in the power law size spectrum of falling bodies. The estimates of the initial temperature of the Earth can vary within wide limits depending on the mass distribution of large protoplanetary bodies, which at the present time is not known correctly. The initial melting of an upper layer of the Earth a few hundred kilometers thick seems to be possible.     

Problems of origin of asteroids and comets

Abstract— Various hypotheses of the origin of asteroids and comets are briefly discussed. Interaction of planetesimals in the asteroid zone (AZ) with the gas, their perturbations by proto-Jupiter, and sweeping them out by more massive Jupiter zone bodies when they penetrated the AZ are considered. If the gas was turbulent, it could prevent a settling of dust particles to the equatorial plane of the disk and formation of dust condensations due to gravitational instability. Then particles grew by sticking upon collision. Gas moved radially due to turbulent viscosity and its dissipation. Small particles moved more-or-less together with the gas. As a result of gas drag, larger particles and bodies moved relative to the gas in the direction of increasing gas pressure. Gas would remove much of the solid material from the AZ if most bodies larger than a few km disintegrated by collisions into fragments smaller than a few tens of meters. Most of these fragments would then move into the Martian zone, and the small mass of Mars would have no explanation. Resonant perturbations of asteroids by Jupiter are discussed. In the model of a small mass disk they could scan through the asteroid belt due to changes in Jupiter's distance from the Sun that occurred when this planet accreted the gas and ejected the bodies from the solar system. Such a scanning considerably accelerated the removal of asteroids from the AZ. Massive Jupiter zone bodies with large orbital eccentricities that crossed the AZ were probably efficient at sweeping out bodies. Larger bodies increased the random velocities of the remaining asteroids at close encounters to the present values ～ 5 km/s. Restrictions on the runaway growth of giant planets, on the relative velocities of bodies and the disk surface density that follow from the consideration of the origin of the asteroid belt and the cometary cloud are considered.     

Carbon monoxide emissions in summer 2010 in the central part of the Russian Plain and estimation of their uncertainties with the use of different land-cover maps

This study is devoted to estimation of carbon monoxide (CO) emissions during the wildfires of the anomalously hot 2010 summer in the central part of the Russian Plain. CO emissions from the forest wildfires have been estimated with use of the Active Fires (AF) (MODIS MCD14ML) and Burned Areas (BA) (MODIS MCD45) methods for AVHRR/UDM, Global Land Cover 2000 (GLC 2000), GlobCover, and MCD12Q1 vegetation maps. A comparison of the vegetation maps and investigation of forest structure dynamics for the period from 2005 to 2009 have been carried out. It is shown that the major uncertainties during the estimation of CO in decreasing order are the following: distinctions in emission-calculation methods, differences in the vegetation maps used, differences in satellite data from Terra and Aqua, and the insufficient registration of forest structure dynamics. For additional comparison of estimations obtained by an independent method with the use of orbital (MOPITT, AIRS, and IASI) and ground-based (Moscow and Zvenigorod) spectroscopic measurements of CO content were presented.