Acceleration of Relativistic Protons During the 20 January 2005 Flare and CME     

S. Masson  K.-L. Klein  R. Bütikofer  E. Flückiger  V. Kurt  B. Yushkov  S. Krucker 《Solar physics》2009,257(2):305-322

The origin of relativistic solar protons during large flare/CME events has not been uniquely identified so far. We perform a detailed comparative analysis of the time profiles of relativistic protons detected by the worldwide network of neutron monitors at Earth with electromagnetic signatures of particle acceleration in the solar corona during the large particle event of 20 January 2005. The intensity – time profile of the relativistic protons derived from the neutron monitor data indicates two successive peaks. We show that microwave, hard X-ray, and γ-ray emissions display several episodes of particle acceleration within the impulsive flare phase. The first relativistic protons detected at Earth are accelerated together with relativistic electrons and with protons that produce pion-decay γ rays during the second episode. The second peak in the relativistic proton profile at Earth is accompanied by new signatures of particle acceleration in the corona within ≈1R _⊙ above the photosphere, revealed by hard X-ray and microwave emissions of low intensity and by the renewed radio emission of electron beams and of a coronal shock wave. We discuss the observations in terms of different scenarios of particle acceleration in the corona.  相似文献   

Internal structural geometry of the Paleozoic of Graz     

Deta Gasser  Kurt Stüwe  Harald Fritz 《International Journal of Earth Sciences》2010,99(5):1067-1081

The Paleozoic of Graz is an isolated nappe complex of about 1,500 km² size and belongs to the Austroalpine units of the eastern European Alps. Despite more than 500 publications on stratigraphy, paleontology and local structure, many aspects of the internal geometry of this complex as a whole remained unclear. In this contribution, we present integrated geological profiles through the entire nappe complex. Based on these profiles, we present (1) a simplified lithological subdivision into 13 rock associations, (2) a modified tectonostratigraphy where we consider only two major tectonic units: an upper and a lower nappe system and in which we abandon the traditionally used facies nappe concept, and (3) a modified paleogeography for the whole complex. Finally, we discuss whether the internal deformation of the Paleozoic of Graz is of Variscan or Eo-Alpine age and which of the published models best explain the tectonic evolution of the Paleozoic of Graz.  相似文献   

Sea level and shoreline reconstructions for the Red Sea: isostatic and tectonic considerations and implications for hominin migration out of Africa     

Kurt Lambeck  Anthony Purcell  Nicholas. C. Flemming  Claudio Vita-Finzi  Abdullah M. Alsharekh  Geoffrey N. Bailey 《Quaternary Science Reviews》2011,30(25-26):3542-3574

The history of sea level within the Red Sea basin impinges on several areas of research. For archaeology and prehistory, past sea levels of the southern sector define possible pathways of human dispersal out of Africa. For tectonics, the interglacial sea levels provide estimates of rates for vertical tectonics. For global sea level studies, the Red Sea sediments contain a significant record of changing water chemistry with implications on the mass exchange between oceans and ice sheets during glacial cycles. And, because of its geometry and location, the Red Sea provides a test laboratory for models of glacio-hydro-isostasy. The Red Sea margins contain incomplete records of sea level for the Late Holocene, for the Last Glacial Maximum, for the Last Interglacial and for earlier interglacials. These are usually interpreted in terms of tectonics and ocean volume changes but it is shown here that the glacio-hydro-isostatic process is an additional important component with characteristic spatial variability. Through an iterative analysis of the Holocene and interglacial evidence a separation of the tectonic, isostatic and eustatic contributions is possible and we present a predictive model for palaeo-shorelines and water depths for a time interval encompassing the period proposed for migrations of modern humans out of Africa. Principal conclusions include the following. (i) Late Holocene sea level signals evolve along the length of the Red Sea, with characteristic mid-Holocene highstands not developing in the central part. (ii) Last Interglacial sea level signals are also location dependent and, in the absence of tectonics, are not predicted to occur more than 1–2 m above present sea level. (iii) For both periods, Red Sea levels at ‘expected far-field’ elevations are not necessarily indicative of tectonic stability and the evidence points to a long-wavelength tectonic uplift component along both the African and Arabian northern and central sides of the Red Sea. (iv) The observational evidence is consistent with tectonic and isostatic processes both operating over the past 300,000 years without requiring changes in the time averaged (over a few thousand years) tectonic rates. (v) Recent bathymetric data for the Bab al Mandab region have been compiled to confirm the location and depth of the sill controlling flow in and out of the Red Sea. Throughout the last 400,000 years the Red Sea has remained open to the Gulf of Aden with cross sectional areas at times of glacial maxima about 2% of that today. (vi) The minimum channel widths connecting the Red Sea to the Gulf of Aden at times of lowstand occur south of the Hanish Sill. The channels are less than 4 km wide and remain narrow for as long as local sea levels are below ?50 m. This occurs for a number of sustained periods during the last two glacial cycles and earlier. (vii) Periods suitable for crossing between Africa and Arabia without requiring seaworthy boats or seafaring skills occurred periodically throughout the Pleistocene, particularly at times of favourable environmental climatic conditions that occurred during times of sea level lowstand.  相似文献   

Spatial Ecology of Pre –Euro‐American Fires in a Southern Rocky Mountain Subalpine Forest Landscape     

William L. Baker  Kurt F. Kipfmueller 《The Professional geographer》2001,53(2):248-262

Natural disturbances such as fires have been widely studied, but less is known about their spatial ecology than about other aspects of them. We reconstructed and mapped pre–Euro‐American fire history in a subalpine forest landscape in southeastern Wyoming, and analyzed the fires using GIS. Mean fire interval varies little with topography (elevation, aspect, slope) and is spatially autocorrelated at distances of at least 2 km. Fires often spread downslope, and spread more than expected from the north and south and less than expected from the west, under the influence of particular synoptic climatic conditions. The landscape of 1868 a.d., at the time of Euro‐American settlement, was strongly influenced by fires. However, it contained large patches of connected forest and few high‐contrast edges, unlike the modern landscape, which is fragmented by industrial forestry and roads. The spatial ecology of the natural fire regime may be a useful guide for management.  相似文献   

MAJOR AND TRACE ELEMENT DETERMINATIONS ON NIST GLASS STANDARD REFERENCE MATERIALS 611, 612, 614 AND 1834 BY INDUCTIVELY COUPLED PLASMA-MASS SPECTROMETRY   总被引：1，自引：0，他引：1  

Kurt HOLLOCHER  Joaquin RUIZ 《Geostandards and Geoanalytical Research》1995,19(1):27-34

We report on the major and trace element composition and homogeneity of NIST (National Institute of Standards and Technology) glass standard reference materials 611, 612, 614, and 1834 for use as microanalytical trace element standards in laser ablation-inductively coupled plasma-mass spectrometry. The four analyzed NIST glasses were not designed as microanalytical standards, but their availability and careful preparation made them obvious candidates. Our data indicate that NIST 1834 is inhomogeneous on a scale of 100 mg with respect to several trace elements. Within analytical uncertainty, NIST 611, 612, and 614 are apparently homogeneous.  相似文献   

TRACE ELEMENT DETERMINATIONS FOR USGS BASALT BHVO-1 AND NIST STANDARD REFERENCE MATERIALS 278, 688 AND 694 BY INDUCTIVELY COUPLED PLASMA-MASS SPECTROMETRY     

Kurt HOLLOCHER  Ahmed FAKHRY  Joaquin RUIZ 《Geostandards and Geoanalytical Research》1995,19(1):35-40

Results are presented for 26 to 30 trace elements determined in four rock reference materials of geochemical interest: USGS Basalt BHVO-1, Rhyolite Obsidian NIST 278, Basalt NIST688, and Phosphate Rock NIST694. Determinations were made by inductively coupled plasma mass spectrometry (ICP-MS). Good agreement was obtained among solution standard comparison and standard addition analytical techniques, and among samples prepared with different dissolution methods. Generally good agreement was obtained between determined trace element values and values reported in the literature.  相似文献   

The boundary-value problem of physical geodesy and its solution     

Kurt Arnolr 《Studia Geophysica et Geodaetica》1965,9(2):113-119

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Ein Pyrrhotin-Gefüge aus der Grube Bayerland bei Waldsassen (Oberpfalz)     

Priv.-Doz. Dr. Kurt v. Gehlen 《Contributions to Mineralogy and Petrology》1962,8(5):315-322

The question of preferred orientation of the a-axes of pyrrhotite in metamorphic ores was studied on a fold of cm-dimension in pyrrhotite-ore from the Bayerland mine. A fabric with very good orientation of (0001) in a single s-plane appeared to be superimposed on the fold fabric. Nevertheless, also a weak preferred orientation of\([11\bar 20]\) (?)//B was found which could have been formed by translation with T = (0001) and\(t = [10\bar 10]\). In this favorable case a partial preservation of an older orientation is probable; the two orientations, however, seem to belong to a single orogenetic phase (main deformation with axis B II afterSpross 1954). The orientation of the c-axes of pyrrhotite was determined conoscopically from polarization figures in reflected light, that of the prism faces with an X-ray texture goniometer. The temperature of recrystallization was apparently about 450–500° C.  相似文献   

Der Küstenrückgang an der Insel Sylt     

Prof. Dr. Kurt Vollbrecht 《Ocean Dynamics》1973,26(4):155-170

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Arsenic in ocean floors   总被引：1，自引：0，他引：1  

Kurt Bostr  m  Sylvia Valdes 《Lithos》1969,2(4):351-360

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