Results 1 - 10 of 626
Results 1 - 10 of 626. Search took: 0.021 seconds
|Sort by: date | relevance|
[en] This paper presents results on the concentration of 137Cs, 90Sr, 3H in water samples from 5 locations in NW Black Sea collected in 1999. In sediment samples, 137Cs, Pu radionuclides and 241Am were determined as well as some major and minor elements by X ray fluorescence. After chemical separation by applying a combined sequential procedure, 239+240Pu, 238Pu and 241Am were measured by high-resolution alpha-spectroscopy. Liquid Scintillation Counting was applied for measuring of 241Pu. For the surface water samples, 137Cs concentration varied between (26.3 ± 3.4) mBq/l and (41.2 ± 5.6) mBq/l. The concentration of 90Sr was of about 11 mBq/l. The concentration of tritium was low between 24 and 7 T.U. Higher radioactive concentrations in sediment were found in the samples collected from the stations located close to Danube river. For 137Cs values up to (128± 6) Bq/kg were found, in agreement to results for NW Black Sea in previous years. The measured concentrations of 239+240Pu, 238Pu radioisotopes are within the range of the values reported in earlier research for the Western Black Sea and Bulgarian Black Sea Coast
[en] Full text: The Western Black Sea region comprises parts of:East European platform, Scythian paltform, North Dobrogea orogen, Moesian paltform, Balkan orogen, Eastern Srednogorie, Strandzha orogen, Karkinit basin, West Black Sea basin, Bourgas basin and Thrace basin. The West Black Sea basin consists of two western branches; northern one-Histria sub-basin (in Romania) and southern one-Kamchia sub-basin (in Bulgaria).The eastern Mosian platform is fringed to North by North Dobrogea rift (Seghedi,2001) and to South by Eastern Srednogorie-Balkan rift zone (ESBRZ). These two rift basins were inverted into orogenic belts. Eastwards to the Western Black Sea basin only a broad transitional zone with complex structure can be outlined. To West the Moesian platforms surrounded by south Carpathian-Balkan thrust-fold belt. Both rift basins restricted the Eastern Moesian platform to north and south, are superimposed on the Hercynian sutures.The North Dobrogea rift basin-on the suture between the south-western edge of East Europen platform and Moesian block, and the ESBRZ-on the suture between Moesian block and peri-Gondwana derived Thracian block. The South Moesian platform margin was repeatedly affected by Mesozoic rifting cycles in the Eastern Srednogorie-Balkan zone (ESBZ), interrupted and followed by compressional events,causing strong platform margin shortening and ultimately its overprinting by the alpine orogen.
[en] Endemic goitre is still an important and underestimated health concern in Turkey. The overall prevalence had been calculated as 30.3% by palpation in a national survey conducted in 1995. However, direct evidence that iodine deficiency (ID) is the major cause of the endemic were lacking until now. We measured sonographic thyroid volumes (STV), urinary iodine concentrations (UIC) in 1226 school age children (SAC) (9-11 year old) from Ankara the capital of Turkey located in the central Anatolia, and three highly endemic goitre areas of the Black Sea region. A considerable number of school age children (SAC) were found to have STV exceeding the recommended upper normal limits for their age and gender obtained from iodine-replete European children (i.e. 26.7, 40.3, 44.8 and 51.7% of children from Ankara, Kastamonu, Bayburt and Trabzon respectively). UIC indicated moderate to severe ID in these areas with median concentrations of 25.5, 30.5, 16.0 and 14 μg/L respectively. This study showed severe to moderate ID as the primary etiological factor for the goitre endemic observed in Ankara and the Black Sea region of Turkey
[en] Complete text of publication follows. Baryatino magnetic anomaly is situated in the central part of the East-European craton, approximately 300 km to the south-west from Moscow. It is caused by ferrous quartzite bodies, occurring within the metamorphic basement. The basement is covered by sedimentary complex with total thickness of 500 m and more, which makes mining of iron ore impractical. However, studies of Baryatino area can provide information about the internal structure of the Archean-Proterozoic basement, which is still poorly understood. In 1992 a geophysical training ground for students of Moscow State University and other universities was established in Alexandrovka village, close to Baryatino area (Khmelevskoy et al., 1999). Since then electromagnetic, electrical, magnetic and gravity measurements are performed in the region. Besides, geological and geophysical information, previously obtained in the area, was collected and analyzed (for example, first magnetic exploration was performed here in 1934). The key method of deep investigations is magnetotellurics (MT). More than a hundred of MT soundings were performed in the region. They allowed to trace the top of metamorphic basement and revealed a conductive anomaly in the consolidated crust. Presumably, it is a northern continuation of Kirovograd crustal anomaly, traced from the Black sea to the North of the Ukraine. Currently, MT soundings are performed in the area between Ukraine and Baryatino anomaly to verify this hypothesis (Varentsov et al., 2008). Controlled-source electromagnetic and electrical methods were applied to study the sedimentary cover. In the lower part there is a conductive Devonian complex, consisting of terrigenous rocks, saturated by high-mineralized water. Above there is a resistive, mainly carbonate Carboniferous complex. Near-surface rocks are conductive quaternary moraine sediments, formed during the ice age. Magnetic and gravity and measurements along several profiles revealed intensive anomalies: magnetic ones reach 28 000 nanoTesla (Brodovoy et al, 2000). They are caused by Proterozoic ferrous quartzite and chlorite schist bodies, opened by deep borehole near Baryatino town. Density and magnetic susceptibility models of the upper part of metamorphic basement were constructed. We would like to thank our colleagues from Moscow State University and from Russian State Geological Prospecting University, who took part in geophysical studies. Our work is supported by RFBR grant 08-05-00327-a.
[en] Evaluation of the available information has shown that the amount of uranium in the several thousand years old sediments on the bottom of the Black Sea is 2 +- 0,5 million tons, i.e. only on third of the amount formerly presumed. Critical evaluation of the characteristics of the sediment (grain size, negative lower heating value, low uranium content appr. 11 ppm in the original conditions) and its effects in large-scale exploitation and use led to the conclusion that this uranium - if usable at all - can not be allocated to the known reserves at present. (The work has been finished in 1978.) (orig.)
[de]Durch Auswertung der verfuegbaren Informationsquellen wird nachgewiesen, dass die auf dem Grund des Schwarzen Meeres in den mehrere tausend Jahre alten Sedimenten vorhandene Uranmenge 2 +- 0,5 Milionen t Natururan betraegt, d.h. nur ein Drittel der urspruenglich vermuteten Menge. Die kritische Auswertung der bekannten Sedimenteigenschaften (Feinkoernigkeit, negativer unterer Heizwert, niedriger Urangehalt um 11 ppm im Lagerungszustand) und ihre Auswirkung auf die grosstechnische Foerderbarkeit und Verwertbarkeit fuehren zu dem Resultat, dass dieses Uranreserven gerechnet werden kann. (Die Arbeit wurde 1978 abgeschlossen.) (orig.)
[en] Cosmogenic 10Be (half-life: 1,5 x 106 years), like 14C, is formed by the interaction of primary and secondary cosmic rays in the earth's atmosphere. This 10Be is rapidly transfered to geophysical reservoirs. The deposition rate of 10Be at these geophysical reservoirs is dependent on the primary cosmic rays and the geomagnetic field intensities, and the solar activity. For this reason the concentration profile of 10Be in various geophysical reservoirs thus potantially contains a continuous record of cosmogenic events in the past 15 millions years. 10Be concentrations in geophysical samples such as polar ice, sea sediments etc., can be successfully measured using a new accelerator spectrometry technique. In this new technique the detection limit of 10Be is about 107 atoms. In this work 10Be concentrations in the Black Sea and the Indian Ocean sediments, have been measured using the Grenoble Cyclotron and it was found that 10Be concentration in the Black Sea sediments (average: 2.25x10810Be atoms/gr. sediment) is nearly 10 times lower than the Indian Ocean sediments (average: 1,95x10910Be atoms/gr. sediment). (author)
[en] The results of radioecological study carried out in the Danube mouth and north-western part of the Black sea in 1986-1988 are presented in comparison with 1960-1970 data. The dynamics of the behaviour of the radionuclides in the Black sea is studied
[en] Some aspects of the seismicity the Crime—Black Sea region are considered on the basis of the catalogued data on earthquakes that have occurred between 1970 and 2012. The complete list of the Crimean earthquakes for this period contains about 2140 events with magnitude ranging from −1.5 to 5.5. Bulletins contain information about compressional and shear waves arrival times regarding nearly 2000 earthquakes. A new approach to the definition of the coordinates of all of the events was applied to re-establish the hypocenters of the catalogued earthquakes. The obtained results indicate that the bulk of the earthquakes’ foci in the region are located in the crust. However, some 2.5% of the foci are located at the depths ranging from 50 to 250 km. The new distribution of foci of earthquakes shows the concentration of foci in the form of two inclined branches, the center of which is located under the Yalto-Alushta seismic focal zone. The whole distribution of foci in depth corresponds to the relief of the lithosphere.