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DION BRANDT WOLF UWE REMOLD ALAN J. FRANZSEN CHRISTIAN KOEBERL LUTZ WENDORFF 《Meteoritics & planetary science》1998,33(3):447-453
Abstract— New gravity and magnetic data were obtained along ground profiles across the Roter Kamm impact crater in the southern Namib desert of Namibia. As the traverses of previous studies did not extend sufficiently beyond the crater rim, it had not been possible to adequately determine the regional background values. The gravity results of this study are similar to those obtained by Fudali in 1973, in that a negative, near-symmetrical anomaly was obtained over the crater center. This anomaly conforms to the results expected for a sediment and impact breccia-filled, simple bowl-shaped crater. The magnetic results of this study, however, are different to those previously reported, which is most probably as a result of the longer profiles used in this new study. A slight positive magnetic anomaly was obtained over the crater interior. Short-wavelength, high-amplitude anomalies observed in the vicinity of the crater rim reflect magnetization contrasts that are probably related to brecciation and block rotation. Modelling of the positive magnetic anomaly indicates the possibility of a small magnetic body or lining at the crater floor-breccia interface in the interior of the crater. Also presented is a 10 m contour digital elevation model of the crater and its environs. 相似文献
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FRIEDRICH-WILHELM HAAKE UWE PFLAUMANN 《Boreas: An International Journal of Quaternary Research》1989,18(4):343-356
Quantitative studies of foraminiferal faunas and isotope ratios have been done in two gravity cores from the Vøring Plateau. Core 23199 from about 2000 m water depth included sediments younger than oxygen Stage 7. Core 23205 from about 1400 m ended in sediments from Stage 5. According to the transfer temperatures, the onset of abundances of Cibicidoides wuellerstorfi and the δ13 C values of Neogloboquadrinapachyderma , the Vøring Plateau was covered by pack-ice during Stages 6,4,2 and, to some extent, also during Stage 3. Ice-free sea-surface conditions prevailed from late Substage 5e throughout Stage 5 and during stage 1. The transition from Stage 6 to Stage 5 (Termination II) took place in two steps: Ila is defined by the δ18 O signal of N. pachyderma (reduced global ice volume) and lib by the increased occurrence of C. wuellerstorfi (melting of local pack-ice). A contemporaneous development of an interglacial deep-water circulation system is indicated. 相似文献
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Geographers have recognized that trade fairs and other temporary spaces function as centers of knowledge, but we have a weak understanding of how fairs are themed spaces, similar to parades, festivals, and built environments, that produce cultural and political meanings. In this article we analyze the morphology, iconography, and performance of a large agricultural fair in Brazil, the Bahia Farm Show, which produces a regional identity of highly productive, leading‐edge, and globally competitive agriculture in a former economic backwater. We discuss the production of themes in terms of power relations, cultural processes, relations with nature, and sociotechnological norms for agriculture. Omissions from the Farm Show indicate tension and accommodation between elites at different geographical scales. Brazil's high‐input, high‐output agriculture relies in part on the meanings that events such as agricultural fairs sustain and reproduce. 相似文献
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A trace-gas climatology above Zotino, central Siberia 总被引：1，自引：1，他引：1
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DAVID W. KICKLIGHTER MICHELE BRUNO SILKE DÖNGES GERD ESSER MARTIN HEIMANN JOHN HELFRICH FRANK IFT FORTUNAT JOOS JÖRG KADUK GUNDOLF H. KOHLMAIER A. DAVID McGUIRE JERRY M. MELILLO ROBERT MEYER BERRIEN MOORE III REAS NADLER I. COLIN PRENTICE WALTER SAUF ANNETTE L. SCHLOSS STEPHEN SITCH UWE WITTENBERG GUDRUN WÜRTH 《Tellus. Series B, Chemical and physical meteorology》1999,51(2):343-366