First Permian–Early Triassic zircon ages for tin-bearing granites from the Gemeric unit (Western Carpathians, Slovakia): connection to the post-collisional extension of the Variscan orogen and S-type granite magmatism     

Ulrike Poller  Pavel Uher  Igor Broska  Dusan Plasienka  & Marian Janák 《地学学报》2002,14(1):41-48

This study presents the first preliminary U–Pb zircon data on tin-bearing S-type granites from the Gemeric unit of the Western Carpathians (Slovakia). U–Pb single zircon dating controlled by cathodoluminescence suggests crystallization of the Gemeric granites during Permian to Early Triassic (303–241 Ma) time. Post-crystallization, low-temperature metamorphic overprint is reflected by partial Pb loss in zircons. These Gemeric granites are younger than the highly fractionated, S-type, tin- and rare-element-bearing leucogranites in the European Variscides. They may have resulted from partial melting, triggered by increased heat flow from the mantle below the continental crust, and most probably intruded during the post-collisional extension and initial rifting of the Variscan orogenic belt. During Alpine orogeny, the Gemeric granites were affected by a low-temperature deformation and metamorphism.  相似文献   

Induced planet formation in stellar clusters: a parameter study of star–disc encounters     

Ingo Thies  Pavel Kroupa †  Christian Theis 《Monthly notices of the Royal Astronomical Society》2005,364(3):961-970

  相似文献   

Partial mixing and formation of the ¹³C pocket by internal gravity waves in asymptotic giant branch stars     

Pavel A. Denissenkov  Christopher A. Tout † 《Monthly notices of the Royal Astronomical Society》2003,340(3):722-732

  相似文献   

On the origin of brown dwarfs and free-floating planetary-mass objects   总被引：1，自引：0，他引：1  

Pavel Kroupa †  Jerome Bouvier 《Monthly notices of the Royal Astronomical Society》2003,346(2):369-380

  相似文献   

Multi-Instrument Observations of Bright Meteors in the Czech Republic     

Pavel Spurný  Jiří Borovička  Pavel Koten 《Earth, Moon, and Planets》2004,95(1-4):569-578

We present detailed data on 8 bright meteors recorded simultaneously by different observational techniques. All meteors were recorded by all-sky cameras at the Czech stations of the European Fireball Network and by image intensified TV cameras placed at Ondrejov and Kunzak observatories. As well as direct photographic and LLLTV recordings, most of meteors were recorded also by the spectral TV camera and some also by photographic spectral cameras. For 6 cases, lightcurves from radiometers with very high time resolution (1200 s⁻¹) are also available. From all these detections we found a significant difference between TV and photographic beginning heights. TV beginnings are in average about 40 km higher than the photographic ones. We found that meteor brightness is up to 2 magnitudes higher in the photographic system than in the TV system. This difference for high velocity meteors is mainly caused by the presence of strong Ca⁺ lines in the blue part of the spectrum, where the image intensifier is only marginally sensitive. At heights above 110 km, the Na line is usually brighter than the Mg line, while at lower heights both lines have comparable brightness. In one of two captured spectra of short duration luminous trains, a small initial brightening of the Mg and Na lines caused by recombination processes was observed.  相似文献   

Fragmentation Model Analysis of EN270200 Fireball     

Pavel Spurn??  Zdenek Ceplecha 《Earth, Moon, and Planets》2004,95(1-4):477-487

  相似文献   

Late reionizations of the Universe and their manifestation in the WMAP and future Planck data     

Pavel Naselsky  Lung-Yih Chiang 《Monthly notices of the Royal Astronomical Society》2004,347(3):795-801

  相似文献   

Holocene marine terraces on two salt diapirs in the Persian Gulf,Iran: age,depositional history and uplift rates     

Ji&#x;í Bruthans  Michal Filippi  Milan Ger&#x;l  Mohammad Zare  Jaroslava Melkov  Anna Pazdur  Pavel Bosk 《第四纪科学杂志》2006,21(8):843-857

Slightly inclined Holocene marine terraces cover parts of two circular salt diapirs (Hormoz and Namakdan) in the Persian Gulf. Their relative altitude above present sea level results from a combination of general marine transgression/regression affecting the whole area, and of local uplift related to salt diapirism. Differential uplift rate of the studied diapirs in centre‐to‐rim profiles was calculated from results based on: (i) radiocarbon ages of skeletal remains of benthic faunas (19 samples), which originally grew close to sea level; (ii) original altitude of samples, estimated from general sea‐level oscillation curves for the last 10 kyr, and (iii) present sample altitude measured in the field. Calculated uplift rates increase from rim to centre on both diapirs in the range from: 2 mm yr^?1 at the rim to 5–6 mm yr^?1 at the interior of Hormoz, and 1–3 mm yr^?1 at the rim to 3–5 mm yr^?1 at the interior of Namakdan. Such uplift rate distributions fit into the parabolic profile of Newtonian fluid rather than to profiles typical for pseudoplastic fluids. The increase in uplift rate with distance from rim to centre of diapirs is gradual as demonstrated also by generally smooth surface of marine terraces. No tectonic dissections were found. The depositional history on both salt diapirs is similar although they are situated more than 100 km apart. Marine sedimentation started at about 9.6k cal. yr BP on Hormoz and at 8.6k cal. yr BP on Namakdan. Owing to rapid transgression, the sea partially truncated both salt diapirs and rapidly deepened, and carbonate mud was deposited on the peripheries of both salt diapirs. Between 7 and 5k cal. yr BP beach deposition replaced carbonate mud. Soon after 5k cal. yr BP, the sea retreated from most of the marine terraces on both salt diapirs. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Dwarf spheroidal satellites: are they of tidal origin?     

Manuel Metz  Pavel Kroupa 《Monthly notices of the Royal Astronomical Society》2007,376(1):387-392

  相似文献   

Preface to special issue on Northern Eurasia regional climate and environmental change     

Pavel Ya. Groisman   《Global and Planetary Change》2007,56(3-4):v

  相似文献