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31.
F. Sipahi A. Kaygusuz Ç. Saydam Eker A. Vural İ. Akpınar 《International Geology Review》2018,60(3):382-400
The geochemical and Sr–Nd–Pb isotope properties, as well as the Laser Ablation Inductively Coupled Plasma and Mass Spectrometry (LA-ICP-MS) U–Pb zircon age, of E?rikar Monzogranite in the eastern Pontides, are primarily investigated in this study with the aim of determining its magma source and geodynamic evolution. The U–Pb zircon age obtained from E?rikar Monzogranite is 78 ± 1.5 Ma, thereby re?ecting the age of monzogranite. The I-type E?rikar Monzogranite comprises quartz, plagioclase (An35–45), orthoclase, muscovite, and biotite. The geochemical analyses of the E?rikar Monzogranite indicate being medium K calc-alkaline, peraluminous, and resembling magmatic arc granite. The E?rikar Monzogranite is enriched in large ion lithophile elements and light rare earth elements relative to high field strength elements. Chondrite-normalized rare earth element patterns have concave upward shapes (LaN/YbN 2.47–8.58) with pronounced negative Eu anomalies (EuN/Eu* = 0.29–0.65). Initial εNd(i) values vary between 1.85 and 2.18 and initial 87Sr/86Sr values between 0.7048 and 0.7067. Fractionation of plagioclase, hornblende, and apatite played an important role in the evolution of E?rikar Monzogranite. The crystallization temperatures of the melts ranged from 770°C to 919°C based on zircon and apatite saturation temperatures. The geochemical and isotopic data suggest being generated by the partial melting of ma?c lower crustal sources. 相似文献
32.
HD 193182 is one of the most interesting stable shell stars and presents stable shell features which seems to be constant over decades. In this research we analyzed optical, ultraviolet and near-infrared spectra of this little-studied shell star. In the meantime we applied model calculations to the measured spectral parameters of HD 193182 in order to present a more complete view of its stellar and envelope characteristics. 相似文献
33.
The multicolor light curves (UBVRI) of HU Vir have been analyzed to study starspots for epochs 1987 and 1989. The term 'photometric
imaging' has been used for predicting cool surface spots by photometric data. Assuming the number of spots and the area are
about the same for the two hemispheres, the distributive solar analogy is introduced as a tool to constrain free values of
spot parameters into unique values. Therefore, final fitting parameters are claimed unique in a sense that they are independent
of free initial guesses. The light and color variations of HU Vir are better explained without polar spots. Finally, the spots
are found to be ∼ 1600 K cooler than the T∼ 5000 K of this cool subgiant and cover ∼ %13.9 of the total surface at ±8.0 degrees
from the equator for the epoch 1987. The spots at the epoch 1989 are found to be ∼ 2040 K cooler covering ∼ % 12.7 area at
± 27°.7 latitudes. Problems of photometric imaging and possible solutions with distributive solar analogy have been discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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35.
Abolghasem Roohi Zulfigar Yasin Ahmet E. Kideys Aileen Tan Shau Hwai Ali Ganjian Khanari Elif Eker‐Develi 《Marine Ecology》2008,29(4):421-434
The invasive ctenophore Mnemiopsis leidyi (Agassiz), which was transported from the Black Sea into the Caspian Sea at the end of the 1990s, has negatively affected the ecosystem of the Caspian Sea. Zooplankton abundance, biomass and species composition were evaluated on the Iranian coast of the Caspian Sea during 2001–2006. A total of 18 merozooplankton (13 species composed of larvae of benthic animals) and holozooplankton (four Copepoda and one Cladocera) species were identified. The total number of zooplankton species found here was 50% less than in a previous investigation performed in the same region in 1996 before the introduction of Mnemiopsis leidyi into the Caspian Sea. Cladocera species seemed to be highly affected by the invasion of Mnemiopsis leidyi; only one species, Podon polyphemoides, remained in the study area, whereas 24 Cladocera species were found in the study carried out in 1996. Whereas among the Copepoda Eurytemora minor, Eurytemora grimmi, Calanipeda aquae dulcis and Acartia tonsa that were abundant before the Mnemiopsis leidyi invasion, only A. tonsa (copepodites and adults) dominated the inshore and offshore waters after the invasion. The maximum in zooplankton abundance (22,088 ± 24,840 ind·m?3) and biomass (64.1 ± 56.8 mg·m?3) were recorded in December 2001 and August 2004, respectively. The annual mean zooplankton abundance during 2001–2006 was in the range of 3361–8940 ind·m?3; this was two‐ to five‐fold less than the zooplankton abundance in 1996. During 2001–2006, the highest abundance and biomass of Mnemiopsis leidyi were observed during summer‐autumn months coincident with warm temperatures and generally when the abundance of other zooplankton organisms was low. 相似文献