174 resultados para Rheinisches Landesmuseum Bonn


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Primary and secondary mineral phases from Holes 1268A (11 samples), 1272A (9 samples), and 1274A (12 samples) were analyzed by electron microprobe in Bonn and Cologne (Germany). Bulk rock powders of these samples were also analyzed geochemically, including major and trace elements (Paulick et al., 2006, doi:10.1016/j.chemgeo.2006.04.011). Ocean Drilling Program (ODP) Leg 209 Holes 1268A, 1272A, and 1274A differ remarkably in alteration intensity and mineralogy, and details regarding their lithologic characteristics are presented in Bach et al. (2004, doi:10.1029/2004GC000744) and Shipboard Scientific Party (2004, doi:10.2973/odp.proc.ir.209.101.2004). Because of the least altered character of peridotite in Hole 1274A, abundant clinopyroxene, orthopyroxene, olivine, and spinel were analyzed at this site. In Hole 1272A, primary silicates are rare and analyses were restricted to some samples that contain traces of olivine and orthopyroxene. Because of the intensity of alteration, Hole 1268A is devoid of primary phases except spinel. Commonly, alteration is pseudomorphic and serpentinization of olivine and orthopyroxene can be distinguished. Accordingly, compositional variations of the alteration minerals with regard to the precursor minerals are one of the issues investigated in this data report.

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The east coast of the AP is highly influenced by cold and dry air masses stemming from the adjacent Weddell Sea. By the contrary, the west coast jointly with the South Shetland Islands are directly exposed to the humid and relatively warm air masses from the South Pacific Ocean carried by the strong and persistent westerly winds. Systematic glaciological field studies are very scarce on both sides of the AP, among them can be mentioned a mass-balance program performed continuously since summer 1998/99 by the Instituto Antártico Argentino (IAA) on Vega Island, James Ross Archipelago, on the northeastern flank of the AP. Another continuous plurianual glaciological research has been initiated in 2010 jointly by the University of Bonn and the IAA at the Fourcade Glacier on King George Island (KGI) within the framework of the ESF project IMCOAST (FK 03F0617B). Two transects of mass balance stakes were installed from the top of the Warszawa Ice Dome down to the border of the glaciers Fourcade and Polar Club, to serve for calibration and validation of modeling efforts. The stakes were measured at the beginning and end of each summer field campaign in November 2010, February - March 2011, January - March 2012, and especially during the austral winter 2012 up to March 2013 every 10 to 14 days depending on weather conditions. During the austral winter 2013 and until June 2014 the measurements were conducted every 20 to 30 days, weather permitting. Snow density was measured as well in every field trip from June 2012 until June 2104, establishing a rather homogeneous value along the different parts of the glacier. Snow density in late summer, rho_s is usually higher than the one in late winter, rho_w. Seasonal average values were calculated for the area covered by the mass balance stakes, being rho_s= 471 Kg/m**3 and rho_w = 363 Kg/m**3.

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Die Niederrheinische Bucht, ein altes tektonisches Senkungsgebiet, dessen Ausdehnung durch die Orte Aachen, Bonn, Duüsseldorf und Duisburg bestimmt ist, bildete während des jüngeren Tertiärs eine Meeresbucht am Südrande des Nordseebeckens. Noch zu Beginn des Pleistocäns erstreckte sich die Nordsee bis in den Raum von Nijmegen, und im Pliocän verlief die Kuüste etwa auf der Linie Maastricht-Kleve. Im Mittelmiocän reichte die Nordsee bis in die nördliche Niederrheinische Bucht. Marines Oberoligocän mit reicher Fauna findet sich noch in der Gegend von Köln. In Verbindung mit den marinen Transgressionen kam es in den inneren Teilen der Niederrheinischen Bucht zu mehr oder weniger ausgedehnten Vermoorungen, die zur Bildung von Braunkohlenflözen führten, unter denen das miocäne Hauptbraunkohlenflöz nordwestlich von Köln eine Mächtigkeit von mehr als 90 m erreicht. Nach NW spaltet sich das Hauptflöz in drei Teilflöze auf, die von oben nach unten als Flöz Garzweiler, Flöz Frimmersdorf und Flöz Morken bezeichnet werden. Diese Flöze können, wie neue Untersuchungen ergaben, eindeutig mit dem marinen Mittelmiocän in Verbindung gebracht werden.