Preferred orientation in experimentally deformed stishovite: implications for deformation mechanisms     

Pamela M. Kaercher  Eloisa Zepeda-Alarcon  Vitali B. Prakapenka  Waruntorn Kanitpanyacharoen  Jesse S. Smith  Stanislav Sinogeikin  Hans-Rudolf Wenk 《Physics and Chemistry of Minerals》2015,42(4):275-285

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Investigations of karstic springs of the Biokovo Mt from the Dinaric karst of Croatia     

Natalija Matić  Krešimir Maldini  Vlado Cuculić  Stanislav Frančišković-Bilinski 《Chemie der Erde / Geochemistry》2012,72(2):179-190

Ten gravity springs from the slopes of the Biokovo Mt, Adriatic coast of Croatia were investigated. Three of them are included in the regional water supply system. The aim of this study was to investigate hydrogeological and geochemical characteristics of watershed, presenting one of the most typical karstic areas in the world.Hydrogeological investigations were performed during two seasons with dye tracing, using Na-fluoresceine which was poured into two pits, observing springs at distances of 1.82–8.8 km. Apparent velocities were 0.21–0.51 cm s^?1. Dye tracing was first time partially effective and second time ineffective, what could be due to immanent ore mineralization, which presents a natural barrier and was discovered by geochemical and mineralogical methods.Concentrations of 17 dissolved and total trace elements were determined first time in groundwater samples. Their concentrations were extremely low, more than 3 orders of magnitude less than allowed by the Croatian directives for the first category of groundwater and drinking water. The mass fractions of 60 elements were determined in 3 representative spring sediments. Highest concentrations of some metals in sediments (mg kg^?1) are: lead 5440, chromium 118, manganese 935, zinc 116 and barium 238. Origin of some elements and mineralogy is discussed.  相似文献   

Scintillations and Interstellar Lévy Flights     

Stanislav Boldyrev  Carl R. Gwinn 《Astrophysics and Space Science》2004,292(1-4):147-153

We present the new model for interstellar scintillations, which assumes that the electron density fluctuations causing the scintillations obey Lévy statistics rather than Gaussian statistics, as was thought previously. Our model explains the observed anomalous scaling of the signal time-width with respect to the pulsar distance, which remained a puzzle for more than 30 years.  相似文献   

First geophysical and shallow ice core investigation of the Kazbek plateau glacier,Caucasus Mountains     

Stanislav S. Kutuzov  Vladimir N. Mikhalenko  Alexi M. Grachev  Patrick Ginot  Ivan I. Lavrentiev  Anna V. Kozachek  Victoria V. Krupskaya  Alexey A. Ekaykin  Levan G. Tielidze  Pavel A. Toropov 《Environmental Earth Sciences》2016,75(23):1488

First-ever ice core drilling at Mt. Kazbek (Caucasus Mountains) took place in the summer of 2014. A shallow ice core (18 m) was extracted from a plateau at ~4500 m a.s.l. in the vicinity of the Mt. Kazbek summit (5033 m a.s.l.). A detailed radar survey showed that the maximum ice thickness at this location is ~250 m. Borehole temperature of ?7 °C was measured at 10 m depth. The ice core was analyzed for oxygen and deuterium isotopes and dust concentration. From the observed seasonal cycle, it was determined that the ice core covers the time interval of 2009–2014, with a mean annual snow accumulation rate of 1800 mm w. eq. Multiple melt layers have been detected. δ¹⁸O values vary from ?25 to ?5‰. The dust content was determined using a particle sizing and counting analyzer. The dust layers were investigated using scanning electron microscopy and X-ray diffraction analysis. Dust can be separated into two categories by its origin: local and distant. Samples reflecting predominantly local origin consisted mainly of magmatic rocks, while clay minerals were a characteristic of dust carried over large distances, from the deserts of the Middle East and Sahara. The calculated average dust flux over three years at Kazbek was of 1.3 mg/cm² a^?1. Neither δ¹⁸O nor dust records appear to have been affected by summer melting. Overall, the conditions on Kazbek plateau and the available data suggest that the area offers good prospects of future deep drilling in order to obtain a unique environmental record.  相似文献   

Multi-methodological approach to evaluate trace elements and major components in wetland system with subsaline and freshwater characteristics     

Vlado Cuculić  Stanislav Frančišković-Bilinski  Halka Bilinski  Krešimir Maldini  Damir Tomas  Nenad Tomašić 《Environmental Earth Sciences》2016,75(20):1351

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Hermannjahnite,CuZn(SO4)2, a new mineral with chalcocyanite derivative structure from the Naboko scoria cone of the 2012–2013 fissure eruption at Tolbachik volcano,Kamchatka, Russia     

Siidra  Oleg I.  Nazarchuk  Evgeny V.  Agakhanov  Atali A.  Lukina  Evgeniya A.  Zaitsev  Anatoly N.  Turner  Rick  Filatov  Stanislav K.  Pekov  Igor V.  Karpov  Gennady A.  Yapaskurt  Vasiliy O. 《Mineralogy and Petrology》2018,112(1):123-134

Mineralogy and Petrology - A new mineral hermannjahnite, ideally CuZn(SO4)2, was found in the sublimates of Saranchinaitovaya fumarole, Naboko scoria cone, where the recent Fissure Tolbachik...  相似文献   

Exoplanet Transit Database. Reduction and processing of the photometric data of exoplanet transits     

Stanislav Poddaný  Luboš Brát  Ondřej Pejcha 《New Astronomy》2010,15(3):297-301

We demonstrate the newly developed resource for exoplanet researchers – The Exoplanet Transit Database. This database is designed to be a web application and it is open for any exoplanet observer. It came on-line in September 2008. The ETD consists of three individual sections. One serves for predictions of the transits, the second one for processing and uploading new data from the observers. We use a simple analytical model of the transit to calculate the central time of transit, its duration and the depth of the transit. These values are then plotted into the observed–computed diagrams (O–C), that represent the last part of the application.  相似文献   

Plant–Arthropod Associations from the Lower Miocene of the Most Basin in Northern Bohemia (Czech Republic): A Preliminary Report     

Jakub PROKOP  Torsten Wappler  Stanislav Knor  Zlatko Kva?ek 《《地质学报》英文版》2010,84(4):903-914

Terrestrial plants and insects currently account for the majority of the Earth's biodiversity, and approximately half of insect species are herbivores. Thus, insects and plants share ancient associations that date back more than 400 Myr. However, investigations of their past interactions are at the preliminary stages in Western Europe. Herein, we present the first results of our study of various feeding damage based on a dataset of nearly 3500 examined plant specimens from the Lower Miocene of the Lagerst?tte Bílina Mine in the Most Basin, Czech Republic. This site provides a unique view of the Neogene freshwater ecosystems. It has long been studied by scientists working in different branches of sedimentology, paleobotany, and paleozoology. The fossils are preserved in three characteristic horizons overlaying the coal seam (Clayey Superseam Horizon, Delta Sandy Horizon, and Lake Clayey Horizon), reflecting paleoenvironmental changes in a short time period of development. The trace fossils are classified as functional feeding groups or “guilds”, without searching for a direct cause or a recent analog host relation. Approximately 23% of specimens of dicotyledonous plant leaves were found to be damaged and associated with some leaf “morphotypes”. Deciduous plant–host taxa, and those with a chartaceous texture typical of riparian habitats, were frequently damaged, such as Populus, recorded with two species Populus zaddachii and Populus populina (57.9% and 31% herbivory levels, respectively), followed by Acer, Alnus, and Carya, averaging almost 30% of damaged leaves/leaflets. There has been evidence of 60 damage types (DT) representing all functional feeding groups recorded at the Bílina Mine, including 12 types of leaf mines and 16 gall-type DT. In total, Lower Miocene of the Lagerst?tte Bílina Mine exhibits a high level of external foliage feeding types (23.7%), and a low level of more specialized DT, such as galls (4.3%) and leaf mines (<1%). A broader comparison based on DT of the main sedimentary environments shows significance supporting different biomes by frequency of damage levels and DT diversities.  相似文献   

A new conglomerate test in palaeomagnetism   总被引：2，自引：0，他引：2  

Stanislav V. Shipunov  Anton A. Muraviev  & Mikhail L. Bazhenov 《Geophysical Journal International》1998,133(3):721-725

The conglomerate test is widely used in palaeomagnetism to date components of natural remanent magnetization with respect to deposition of conglomerates. It has been demonstrated, however, that this test may be positive even if the data are strongly contaminated by a secondary remanence, especially for the commonly used small number of clasts Starkey & Palmer 1970). Here we show with the aid of numerical simulations that different statistical procedures employed in this test have similar low sensitivities to remagnetization. We suggest a new conglomerate test which incorporates additional information on the direction of a secondary palaeomagnetic component which is isolated from either clasts themselves or their host rocks. Numerical simulations show that this new test is about twice as sensitive to remagnetization as the previous procedures and is robust with respect to small errors in the direction of a secondary component.  相似文献   

Asteroid 2002NY40 as a source of meteorite-dropping bolides     

Josep M. Trigo-Rodríguez  Esko Lyytinen  Daniel C. Jones  José M. Madiedo  Alberto J. Castro-Tirado  Iwan Williams  Jordi Llorca  Stanislav Vítek  Martin Jelínek  Blanca Troughton  Francisco Gálvez 《Monthly notices of the Royal Astronomical Society》2007,382(4):1933-1939

The existence of asteroidal meteoroid streams capable of producing meteorite-dropping bolides has long being invoked, but evidence is scarce. Recent modelling of previously reported associations suggests that the time-scales to keep the orbital coherence of these streams producing meteorites are too short. We present an unequivocal association between near earth object (NEO) 2002NY40 and at least one bright fireball detected over Finland in 2006 August. Another two additional fireballs recorded from Spain and Finland seem to be related, together producing a fireball-producing stream (β Aquarids). On the basis of historical data, the 2006 finding suggests the existence of a meteoroid complex capable of producing meteorites. Taking into account present time-scales for orbital decoherence, if 2002NY40 has large meteoroids associated with it, such behaviour would be the consequence of a relatively recent asteroidal fragmentation. Supporting our claim, the heliocentric orbits of two recently discovered NEOs, 2004NL8 and 2002NY40, were found to exhibit a good similarity to each other and also to the orbits of the three bolides. The fireball spectra of the two Finish bolides showed that the chemical abundances of these objects are consistent with the main elements found in chondrites. This result is consistent with the probable Low iron, Low metal (LL) chondritic mineralogy of asteroid 2002NY40. Consequently, this asteroid may be delivering LL chondrites to the Earth. Additional fireball reports found in the literature suggest that the associated β Aquarid complex may have been delivering meteorites to the Earth during, at least, the last millennium.  相似文献