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Slobodan A. Radosavljević Jovica N. Stojanović Ana S. Radosavljević-Mihajlović Nikola S. Vuković 《Mineralogy and Petrology》2014,108(1):111-122
Rujevac is a low-temperature hydrothermal polymetallic Sb-Pb-Zn-As vein-type ore deposit, hosted within a volcanogenic-sedimentary zone situated in the Rujevac-Crvene Stene-Brezovica Diabase-Chert Formation (DCF) of the Podrinje Metallogenic District (PMD), Serbia. It is located several kilometers SE from the Boranja contact aureole, which is an integral part of the PMD in Western Serbia. Genetically related to the Tertiary granodioritic magma, the mineral assemblages are characterized by specific features. The mineral association of this deposit consists of sulfides, Pb-Sb(As) sulfosalts, native metals, oxides, hydroxides and gangue minerals. Chemical composition of the ore is very complex, where contents of valuable metals range as follows: Sb (0.17–24.31 wt.%), Zn (0.21–6.29 wt.%), Pb (0.15–6.33 wt.%), As (0.06–1.28 wt.%), Cd (25–747 ppm), Ag (7–408 ppm), Hg (13–473 ppm), and Tl (<1–29 ppm). Electron Probe Microanalyses (EPMA) of native arsenic from both the Rujevac and Stragari deposits showed contents of As up to 98.8 and 97.1 wt.%, with impurity contents of Sb up to 1.3 and 6.6 wt.%, and Tl up to 2 and 1.3 wt.%, respectively. Rhombohedral unit-cell parameters for native arsenic from Rujevac and Stragari deposits amount to: a?=?3.760(2), c?=?10.555(3) Å, V?=?129.23(7) Å3 and a?=?3.763(1), c?=?10.560(5) Å, V?=?129.48(8) Å3, respectively. Mineral assemblages, deposition order and genesis of the Rujevac polymetallic deposit were also discussed in detail. Native arsenic mineralization here has been additionally compared with similar well-known global deposits. 相似文献
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François Bache Speranta‐Maria Popescu Marina Rabineau Christian Gorini Jean‐Pierre Suc Georges Clauzon Jean‐Louis Olivet Jean‐Loup Rubino Mihaela Carmen Melinte‐Dobrinescu Ferran Estrada Laurent Londeix Rolando Armijo Bertrand Meyer Laurent Jolivet Gwénaël Jouannic Estelle Leroux Daniel Aslanian Antonio Tadeu Dos Reis Ludovic Mocochain Nikola Dumurdžanov Ivan Zagorchev Vesna Lesić Dragana Tomić M. Namık Çağatay Jean‐Pierre Brun Dimitrios Sokoutis Istvan Csato Gülsen Ucarkus Ziyadin Çakır 《Basin Research》2012,24(2):125-153
The Messinian Salinity Crisis is well known to have resulted from a significant drop of the Mediterranean sea level. Considering both onshore and offshore observations, the subsequent reflooding is generally thought to have been very sudden. We present here offshore seismic evidence from the Gulf of Lions and re‐visited onshore data from Italy and Turkey that lead to a new concept of a two‐step reflooding of the Mediterranean Basin after the Messinian Salinity Crisis. The refilling was first moderate and relatively slow accompanied by transgressive ravinement, and later on very rapid, preserving the subaerial Messinian Erosional Surface. The amplitude of these two successive rises of sea level has been estimated at ≤500 m for the first rise and 600–900 m for the second rise. Evaporites from the central Mediterranean basins appear to have been deposited principally at the beginning of the first step of reflooding. After the second step, which preceeded the Zanclean Global Stratotype Section and Point, successive connections with the Paratethyan Dacic Basin, then the Adriatic foredeep, and finally the Euxinian Basin occurred, as a consequence of the continued global rise in sea level. A complex morphology with sills and sub‐basins led to diachronous events such as the so‐called ‘Lago Mare’.This study helps to distinguish events that were synchronous over the entire Mediterranean realm, such as the two‐step reflooding, from those that were more local and diachronous. In addition, the shoreline that marks the transition between these two steps of reflooding in the Provence Basin provides a remarkable palaeogeographical marker for subsidence studies. 相似文献
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GPS results for Macedonia and its importance for the tectonics of the Southern Balkan extensional regime 总被引：1，自引：2，他引：1
B. Clark Burchfiel Robert W. King Angel Todosov Valentin Kotzev Nikola Durmurdzanov Todor Serafimovski Bilbil Nurce 《Tectonophysics》2006,413(3-4):239-248
GPS results from 25 stations in Macedonia measured in 1996 and 2000 show that Macedonia moves SSE relative to Eurasia essentially as a single crustal piece along with parts of westernmost Bulgaria. Geological studies show active N–S normal faults and two NNW-striking right-lateral faults in western Macedonia, and NW-trending left-lateral faults SE Macedonia, with a region in central Macedonia essentially devoid of active faults. Distribution of seismic activity supports the geological studies. However, the GPS results cannot discriminate the active faulting, except perhaps in the northern part of Macedonia in the Skopje and adjacent areas, where active ~NS extension occurs. Slip-rates on the strike-slip faults must be low, in the range of 0–2 mm/year. There is a progressive increase in GPS velocities southward in northern Greece toward the North Anatolian fault zone, across which the velocities increase and change direction dramatically. 相似文献
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Bojan Lazar Romana Gračan Jelena Katić Dušan Zavodnik Andrej Jaklin Nikola Tvrtković 《Marine Ecology》2011,32(1):65-74
Molluscs are a diverse and ubiquitous group of organisms which contribute to the formation of biogenic sediments and are one of the major prey taxa for the neritic‐stage loggerhead sea turtles (Caretta caretta) worldwide. Here we investigated to what degree molluscs contribute to the diet of individual turtles, and what role the feeding strategy of loggerheads might play in bioturbation, one of the key processes in nutrient transport in marine ecosystems. We performed a detailed analysis of benthic molluscs from the digestive tracts of 62 loggerhead sea turtles (curved carapace length: 25.0–85.4 cm) found in the Northern Adriatic Sea. From 50 of the turtles that contained benthic molluscs, we identified 87 species representing 40 families and three classes (Gastropoda, Bivalvia and Scaphopoda), including 72 new dietary records for loggerhead turtle. Most of the identified molluscs were small‐sized species (shell length ≤ 3 cm) and were often found in a subfossil condition. Their intake may be considered a byproduct of infaunal mining, while larger molluscs were mainly found crushed into smaller fragments. Through such foraging behaviour loggerheads actively rework sediments, increase the surface area of shells and the rate of shells disintegration, acting as bioturbators in this system. We conservatively estimate that loggerheads in the neritic zone of the Adriatic Sea bioturbate about 33 tonnes of mollusc shells per year, and hypothesize about the possible effects of bioturbation reduction on environmental changes in the Northern Adriatic ecosystem. 相似文献
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Nikola Solarić 《Astrophysics and Space Science》1991,177(1-2):169-173
The paper presents the automatic time recording of transits of the image of a star across the hairs in the visual field of a telescope and the automatic reception of radio time signals for the determination of astronomical latitude and longitude of a station using an astrolabe. The automatization was achieved by an electronic calculator Hewlett Packard HP41CX and an especially constructed relay. The method proved very practical in the course of making the network of geoidal points more dense for the needs of geodesy. 相似文献
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Burazer Nikola Šajnović Aleksandra Kašanin-Grubin Milica Radisavljević Marija Jovančićević Branimir 《Journal of Paleolimnology》2021,66(3):187-205
Journal of Paleolimnology - The study investigated the influence of maturity, biomass type, and depositional settings on the distribution and relative abundance of polycyclic aromatic hydrocarbons... 相似文献
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Milica?G.?Radakovi? Ivana?To?i?Email author Nikola?Ba?evi? Dragan?Mladjan Milivoj?B.?Gavrilov Slobodan?B.?Markovi? 《Theoretical and Applied Climatology》2018,133(3-4):887-898
In this study, we apply De Martonne and Pinna combinative indices to analyze the aridity in Central Serbia. Our dataset consists of mean monthly surface air temperature (MMT) and mean monthly precipitation (MMP) for 26 meteorological stations during the period 1949–2015. MMT and MMP are used for calculating monthly, seasonal, and annual aridity indices for period of 66 years. According to the De Martonne climate classification, we determine five, three, and four types of climate on the monthly, seasonal, and annual basis, respectively. During the observed period, winter was extremely humid, spring and autumn were humid, and summer was semi-humid. Humid and semi-humid climate with Mediterranean vegetation are identified by the annual Pinna combinative index. We find that there is no change in aridity trend in Central Serbia for the period 1949–2015. Aridity indices are additionally compared with the North Atlantic Oscillation and El-Niño South Oscillation in order to establish a possible connection with the large-scale processes. Results are further compared with several earlier studies of aridity in Serbia. With this study, the analysis of aridity in whole Serbia has become complete. 相似文献