Age and palynological characteristic of the Dongning Formation (Eastern Heilongjiang,China)

The taxonomic composition of the palynological assemblage of the Dongning Formation is supplemented. The palynological assemblage corresponds to those from the Lipovtsy Formation (Aptian) in the Razdolnaya Basin of Primorye (Russia) and the Muling Formation (Aptian) in the Jixi Basin of eastern Heilongjiang (China). It is found that the age of the Dongning Formation is Aptian. The palynological assemblage is characterized by dominance of spores of Gleicheniaceae; they are accompanied by spores of Cyatheaceae. The most important feature of the palynological assemblage of the Dongning Formation is the presence of angiosperm pollen (Tricolpites sp., T. micromunus, T. vulgaris, Retitricolpites georgiensis, R. vulgaris, Clavatipollenites hughesii, Quercites sparsus, Fraxiniopollenites variabilis).     

Shallow depth extent of the Lesutoskraal granophyre dike in the Vredefort impact structure: Geophysical surveys and trenching data

Recent observations and geophysical studies at the Vredefort impact structure have indicated that the impact melt dikes in the central uplift of the structure have small depth extents. In this study, we performed magnetic and electrical resistivity tomography (ERT) surveys of the Lesutoskraal granophyre dike (LGD) and trenched to confirm its depth extent. The ERT survey showed that outcrops of the LGD are associated with shallow resistive zones with <3 m depth extent, but such zones do not occur where outcrops are absent. Visual observations in the trench confirmed that the dike has a small depth extent (~0.75 m) at this location. However, the magnetic survey revealed anomalies along the entire strike of the dike, even where no outcrops occur. We suggest that remagnetization of the host rock within a metamorphic contact aureole could explain the presence of magnetic anomalies in the absence of outcrops. Considering the results of the ERT survey, the observations made in the trench, and the surface distribution of outcrops of the LGD, we confirm that this dike has a small depth extent (<3 m) along its entire length and propose that outcrops represent the intersection of the dike terminus with the current erosional surface.     

Variable binaries and variables in binaries in the Binary star DataBase

The Binary star DataBase(BDB, http://bdb.inasan.ru) combines data from catalogs of binary and multiple stars of all observational types. There is a number of ways for variable stars to form or to be a part of binary or multiple systems. We describe how such stars are represented in the database.     

Binary Star Population with Common Proper Motion in Gaia DR2

Astronomy Reports - We describe a homogeneous catalog compilation of common proper motion stars based on Gaia DR2. A preliminary list of all pairs of stars within the radius of 100 pc around the...     

Assessing the trophic state of water bodies by high-resolution remote spectrometry in visible band

Analysis is presented of many-year spectrometric data in the visible band of electromagnetic spectrum collected for the Don R., including the Tsimlyansk Reservoir in 2010–2013 with a period of ~15 days. An algorithm has been proposed for separating spectral brightness coefficient of the rising radiation from water into six categories. A nomenclature scale of the trophic status of water bodies has been constructed. The obtained scale coincides with the nomenclature scales constructed by chlorophyll a concentration for water bodies under different physiographic conditions. The unquestioning advantage of remote sensing methods for assessing water body (WB) trophic status is emphasized, i.e., the possibility to carry out real-time studies within minutes at high representativeness of the results with respect to the examined aquatic ecosystem.     

A new species of Platanus from the Cenomanian(Upper Cretaceous) in eastern Heilongjiang,China

The stratigraphic division and sequence of the Upper Cretaceous sediments in eastern Heilongjiang Province,China,have been ambiguous and controversial,mainly due to a lack of biostratigraphically useful fossils and related radiometric dating.A new species of angiospermous fossil plant.Platanus heilongjiangensis sp.nov.,from Qitaihe in eastern Heilongjiang has been found in sediments conformably above which zircons from a rhyolitic tuff has been dated by U-Pb radiometric methods as 96.2± 1.7 Ma.indicating that the Upper Houshigou Formation is of Cenomanian age.This discovery not only provides new data to improve our stratigraphic understanding of the Houshigou Formation,but also shows that Platanus flourished in the early Late Cretaceous floras of the region.This new study also indicates active volcanism taking place in the eastern Heilongjiang region during the Cenomanian of the Late Cretaceous.     

Transformation of the molecular and supramolecular structure of ozokerite under thermal effect

The transformation of the molecular and supramolecular structure under the thermal effect of ozokerites from the Yarega, Russia; the Borislav, Ukraine; and the Shorsu, Uzbekistan deposits was studied. The elemental analysis, infrared spectroscopy, thermal and X-ray diffraction analyses, gas-liquid and pyrolytic chromatography, gas chromatography-mass spectrosopy, and scanning electron and atomic force microscopy were used. Heating up to 500°C results, first of all, in a decrease in the relative amounts of normal paraffins. Significant transformations at the supramolecular level consist in the enlargement of previously existing structural elements and the formation of new supramolecular units.     

Age and metallicity estimates for moderate-mass stars in eclipsing binaries

We estimate the ages and metallicities for the components of 43 binary systems using a compilation of accurate observational data on eclipsing binaries for which lines of both components are visible in their spectra, together with two independent modern sets of stellar evolution models computed for a wide range of masses and chemical abundances. The uncertainties of the resulting values are computed, and their stability is demonstrated. The ages and metallicity are compared with those derived in other studies using different methods, as well as with independent estimates from photometric observations and observations of clusters. These comparisons con firm the reliability of our age estimates. The resulting metallicities depend significantly on the choice of theoretical model. Comparison with independent estimates favors the estimates based on the evolutionary tracks of the Geneva group.     

Early Cretaceous flora from coal-bearing strata of Markovsky Peninsula in South Primorye，Russia

The Early Cretaceous flora from the coal-bearing strata(Ussuri and Lipovtsy formations)in the Markovsky peninsula of South Primorye,Far East Russia,is reported in some detail in this paper.The flora containing over 80 species of about 50 genera can be divided into two assemblages.The paleofloristic characteristics and the comparisons of this flora with its coeval floras from the adjacent region of the eastern Heilongjiang of Northeast China,indicate the flora and its coal-bearing strata of the Markovsky peninsula can be compared to those of the Chengzihe and Muling formations of the Jixi area of Heilongjiang,representing probably the late Barremian and Aptian age,respectively.