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761.
The reported systemic velocities of the low-mass X-ray binaries (=LMXBs) are found to be unreliable, because of intrinsic Doppler shifts. We argue that the non-globular-cluster LMXBs form a disk population, whose typicalz-velocities are unlikely to exceed 30 km s–1. They are moderately old and rare (among neutron-star sources) and have oscillated through the disk a number of times.  相似文献   
762.
The true orbit of a spacecraft differs from its reference orbit by small deviations due to erros in planetary and initial data, radiation and impact accelerations, and correction terms to Newton's theory of gravitation. These distortions are usually small enough to haveadditive effects on range, at the 10 m accuracy level, throughout the mission. Closed form expressions are derived (in cylindrical coordinates) for thedeviation inrange due to any given perturbing acceleration.  相似文献   
763.
Based on maps of the extragalactic radio sources Cyg A, Her A, Cen A, 3C 277.3 and others, arguments are given that the twin-jets from the respective active galactic nucleus ram their channels repeatedly through thin, massive shells. The jets are thereby temporarily choked and blow radio bubbles. Warm shell matter in the cocoon shows up radio-dark through electron-scattering.  相似文献   
764.
The 2003 Ml = 5.4 Rambervillers earthquake, north-east of France, is the largest seismic event recorded north of the Alps since the 1992 Ms = 5.3, I0 = VII, Roermond earthquake, Netherlands. With a maximum macroseismic intensity of VI-VII EMS-98, the 2003 event was broadly felt to a distance of 300 km from the epicentre. It provides a unique opportunity to test and compare the different procedures used in France, Germany and Switzerland when evaluating macroseismic intensities. The main purpose of this paper is to present a common transfrontier macroseismic map based on the EMS-98 intensity scale. Maximum horizontal accelerations recorded in the area are compared to the intensity values, and we propose to use a differential technique to re-estimate the magnitude of the 1682 Remiremont, I0 = VIII, earthquake, which occurred 40 km south of Rambervillers.  相似文献   
765.
The provenance of Cenomanian to Eocene flysch deposits accreted along the northern margin of the Eastern Alps has been investigated by means of zircon fission-track (FT) geochronology and zircon morphology. The Rhenodanubian flysch and Ybbsitz klippen zone comprise several nappes representing the Main flysch and Laab basins. The Laab basin received sediments of stable European provenance, indicated by pre-Variscan, Variscan, and Permian–Triassic zircon FT ages, and was thus located in the immediate south of the European margin. The Main flysch basin was supplied mainly from the evolving Eastern Alps and was therefore situated south of the Laab basin. Zircon populations with Permian to Jurassic cooling ages in the Main flysch basin are related to increased heat fluxes during the break-up of Pangaea and are probably derived from the northwestern part of the Eastern Alps. The dominant Cretaceous zircon FT cooling ages reflect Eoalpine metamorphism in the Austroalpine realm.  相似文献   
766.
767.
The Teplá Crystalline unit (TCU), western Bohemian Massif, proves highly suitable for studying the effects of differential metamorphic reworking on the U–Th–Pb systematics in monazite, as the overprint of Variscan regional metamorphism onto high-grade Cadomian paragneisses intensifies progressively towards the northwest. Although variably hampered by scarcity, small size, and low uranium contents of monazite, isotope dilution–thermal ionisation mass spectrometry of monazite from paragneisses from the garnet, staurolite, and kyanite zones of the TCU gives a narrow 206Pb/238U age range from 387 to 382 Ma for Variscan peak metamorphism. These data are supported by 382–373 Ma monazite ages derived from electron microprobe analyses. Inheritance of older components in grains from the central TCU imply major “resetting” of pre-Variscan monazite around 380 Ma, possibly due to widespread garnet growth during Variscan metamorphism, which led to the consumption of pre-Variscan high-Y monazite and subsequent growth of new low-Y monazite. Concordant 498–494 Ma monazite ages in a migmatitic paragneiss close to the adjacent Mariánské Lázně Complex (MLC) grew in response to metagabbro emplacement in the MLC from 503 to 496 Ma and not during either Cadomian or Variscan regional metamorphism. Backscatter imaging and electron microprobe analyses reveal that discordant monazite of the migmatite comprises a mix of various age domains that range from ca. 540 to 380 Ma. Combined evidence presented here suggests that instead of Pb loss by volume diffusion, the apparent resetting of the U–Th–Pb systematics in monazite rather involves new crystal growth or regrowth by recrystallisation and dissolution/reprecipitation.  相似文献   
768.
In this paper we present thermal characteristics of coal fires as measured during simulated fires under an experimental setting in Germany in July 2002. It is thus a continuation of the previously published paper “Thermal surface characteristics of coal fire 1: Results of in-situ measurement”, in which we presented temperature measurements of real subsurface coal fires in China [Zhang, J., Kuenzer, C., accepted for publication. Thermal Surface Characteristics of Coal Fires 1: Results of in-situ measurements. Accepted for publication at Journal of Applied Geophysics.]. The focus is on simulated coal fires, which are less complex in nature than fires under natural conditions. In the present study we simulated all the influences usually occurring under natural conditions in a controllable manner (uniform background material of known thermal properties, known ventilation pathways, homogeneous coal substrate), creating two artificial outdoor coal fires under simplified settings. One surface coal fire and one subsurface coal fire were observed over the course of 2 days. The set up of the fires allowed for measurements not always feasible under “real” in-situ conditions: thus compared to the in-situ investigations presented in paper one we could retrieve numerous temperature measurements inside of the fires. Single temperature measurements, diurnal profiles and airborne thermal surveying present the typical temperature patterns of a small surface-and a subsurface fire under undisturbed conditions (easily accessible terrain, 24 hour measurements period, homogeneous materials). We found that the outside air temperature does not influence the fire's surface temperature (up to 900 °C), while fire centre temperatures of up to 1200 °C strongly correlate with surface temperatures of the fire. The fires could heat their surrounding up to a distance of 4.5 m. However, thermal anomalies on the background surface only persist as long as the fire is burning and disappear very fast if the heat source is removed. Furthermore, heat outside of the fires is transported mainly by convection and not by radiation. In spatial thermal line scanner data the diurnal thermal patterns of the coal fire are clearly represented. Our experiments during that data collection also visualize the thermal anomaly differences between covered (underground) and uncovered (surface) coal fires. The latter could not be observed in-situ in a real coal fire area. Sub-surface coal fires express a much weaker signal than open surface fires and contrast only by few degrees against the background. In airborne thermal imaging scanner data the fires are also well represented. Here we could show that the mid-infrared domain (3.8 μm) is more suitable to pick up very hot anomalies, compared to the common thermal (8.8 μm) domain. Our results help to understand coal fires and their thermal patterns as well as the limitations occurring during their analysis. We believe that the results presented here can practicably help for the planning of coal fire thermal mapping campaigns — including remote sensing methods and the thermal data can be included into numerical coal fire modelling as initial or boundary conditions.  相似文献   
769.
New laser ablation-inductive coupled plasma-mass spectrometry U-Pb analyses on oscillatory-zoned zircon imply Early Miocene crystallization (18.64 ± 0.11 Ma) of the Pohorje pluton at the southeastern margin of the Eastern Alps (northern Slovenia). Inherited zircon cores indicate two crustal sources: a late Variscan magmatic population (~270–290 Ma), and an early Neoproterozoic one (850–900 Ma) with juvenile Hf isotope composition close to that of depleted mantle. Initial εHf of Miocene zircon points to an additional, more juvenile source component of the Miocene magma, which could be either a juvenile Phanerozoic crust or the Miocene mantle. The new U-Pb isotope age of the Pohorje pluton seriously questions its attribution to the Oligocene age ‘Periadriatic’ intrusions. The new data imply a temporal coincidence with 19–15 Ma magmatism in the Pannonian Basin system, more specifically in the Styrian Basin. K-Ar mineral- and whole rock ages from the pluton itself and cogenetic shallow intrusive dacitic rocks (~18–16 Ma), as well as zircon fission track data (17.7–15.6 Ma), gave late Early to early Middle Miocene ages, indicating rapid cooling of the pluton within about 3 Million years. Medium-grade Austroalpine metamorphics north and south of the pluton were reheated and subsequently cooled together. Outcrop- and micro scale structures record deformation of the Pohorje pluton and few related mafic and dacitic dykes under greenschist facies conditions. Part of the solidstate fabrics indicate E–W oriented stretching and vertical thinning, while steeply dipping foliation and NW–SE trending lineation are also present. The E–W oriented lineation is parallel to the direction of subsequent brittle extension, which resulted in normal faulting and tilting of the earlier ductile fabric at around the Early / Middle Miocene boundary; normal faulting was combined with strike-slip faulting. Renewed N–S compression may be related to late Miocene to Quaternary dextral faulting in the area. The documented syn-cooling extensional structures and part of the strike-slip faults can be interpreted as being related to lateral extrusion of the Eastern Alps and/or to back-arc rifting in the Pannonian Basin.  相似文献   
770.
In the sedimentary sequence of the Lower Himalayas monotonous geosynclinal deposits are overlain by various shallow-water deposits and a carbonate rock complex at the top. The age of this nonfossiliferous sequence is discussed. Transgressive Jurassic-Tertiary beds are evidence for a minimum thrust distance of 90 km of the Chail Nappes. The facies distribution points to the importance of an axis parallel to the Himalayan strike direction since Lower Paleozoic at least. The metamorphism of the overthrust units is described and the relation to the evolution of the orogen is discussed. An outline of the structure is given. The type of deformation and other features characteristic of the different tectonic units, as well as the relationship to the geology of the whole Himalayas are discussed. It is emphasized that structural development during the Himalayan orogenesis was largely determined by the earlier paleogeographic history. The picture of the structural development in successive stages is given.
Zusammenfassung In der Sedimentfolge des Niederen Himalaya folgen über einförmigen Geosynklinalsedimenten wechselhafte Scichtwassersedimente mit einem abschließenden Karbonatgesteinskomplex. Das Alter dieser fossilleeren Schichtfolge ist noch nicht endgültig gesichert und wird diskutiert. Darüber liegen transgressiv Jura-Tertiär, deren Vorkommen bis 90 km unter die überschobenen Einheiten nach N reichen. Aus der Faziesanordnung ergibt sich eine Anlage der Himalaya-streichrichtung schon mindestens seit dem Altpaläozoikum. Die Metamorphose der überschobenen Decken wird beschrieben und die Möglichkeiten des Zusammenhanges mit der Orogenentwicklung diskutiert. Es werden die Grundzüge des tektonischen Baues, der charakteristische tektonische Stil der einzelnen Einheiten und deren Beziehungen zur Geologie des gesamten Himalayas beschrieben. Die Entwicklung während der Himalayaorogenese ist stark von der paläogeographischen Ausgangssituation bestimmt. Ein Bild der tektonischen Entwicklung in aufeinanderfolgenden Stadien wird gegeben.

Résumé Dans la séquence sédimentaire du Bas Himalaya les sédiments géosynclinaux monotones sont couverts par des dépôts variables de faciès peu profond qui se terminent avec un ensemble de roches carbonatées. L'âge de cette séquence de couches non fossilifères n'est pas encore fixé et sera discuté. Audessus se trouvent des couches transgressives du Jurassique au Tertiaire qui s'étendent vers le N jusqu'à 90 km au-dessous des nappes chevauchantes. La position des faciès montre que la direction axiale du Himalaya existe au moins depuis le Paléozoique inférieur. Le metamorphisme des nappes charriées est décrit et les possibilités d'une connection avec l'évolution orogénique sont discutées. Les principaux traits de la structure et le style téctonique caractéristique des différentes unités ainsi que leur position dans l'ensemble géologique du Himalaya sont décrits. L'orogénèse du Himalaya est déterminée notamment par la situation paléogéographique. Enfin les différentes phases de l'évolution tectonique sont décrites.

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