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351.
P. Keller Eawag 《Aquatic Sciences - Research Across Boundaries》1964,26(2):628-641
Ohne Zusammenfassung 相似文献
352.
Volcanism in the Mediterranean fold belts is dominantly related to plate-convergence processes. The occurrence of highly potassic and often leucite-bearing lavas is a typical feature of many Neogene to Quaternary volcanic provinces in the Mediterranean area.The paper describes possible relationships between the Aeolian island arc and the Roman comagmatic region and presents petrological evidence for an ultrapotassic province within the Cypriot-Taurus arc of Turkey. It is thus a contribution to the controversy about tectonic setting and geodynamic significance of the highly potassic volcanism of the Mediterranean suite. 相似文献
353.
Jrg Keller 《Journal of Volcanology and Geothermal Research》1981,9(4):423-431
Extrusive carbonatites are described from the Miocene alkaline complex of the Kaiserstuhl, Rhinegraben, Western Germany. Agglutinated carbonatitic lapilli form pyroclastic rocks in which all components show forms acquired when a highly fluid melt was sprayed into the air by an explosive eruption: droplets, spherical and elliptical lapilli, rods, dumbbell and pear-shaped forms.Complete morphological analogies suggest a mechanism similar to the formation of “Pele's tears”, basaltic droplets formed by the eruption of the most fluid Hawaiian basaltic magmas. Evidence is provided by this example that CaCO3-carbonatitic magmas can exist in nature under surface conditions displaying extremely low viscosity. 相似文献
354.
Oceanology - The article presents data indicating the relationship of the bathymetric distribution of solitary endemic scleractinian corals inhabiting the Antarctic continental shelf and upper... 相似文献
355.
Lynchets are ridges formed by erosion and sediment accumulation downstream of agricultural plots and offer valuable insights into past agricultural activity. These microtopographies cover vast areas and serve as indicators of historical changes in land use. As a result, their ubiquity across Europe makes them particularly interesting. In this study, we propose a geoarchaeological approach to analyze six lynchets, four in the Vosges Mountains and two on the Lorraine Plateau (France). The lynchets can be considered soil archives with no stratigraphic organization or chronological sequence from bottom to top, making it difficult to determine the age of the lynchets and identify changes in land use over time. To this end, we propose the analysis of historical and geo-historical archives combined with the “pedosedimentary” archives of lynchets through charcoal identification and dating combined with near-infrared spectroscopy to determine the age, vegetation, and past land use changes associated with lynchet landscapes. By combining these multiple data sources, we are better able to show the chronological development of these ancient agricultural systems and uncover valuable information on landscape history. Charcoal dating suggests a higher frequency of fires from the Middle Ages. The dating aligns with the regional dynamics of anthropogenic fires, indicating a potential use of fire for cultural purposes. We also demonstrate the difficulty of extrapolating the dating of a lynchet to the entire lynchet system. Our results highlight the difficulties of interpreting the formation and dating of lynchets and the lynchet system on the sole basis of charcoal analysis. However, we highlight the value of applying pedoanthracology to lynchets to determine the dynamics of land use change in former fields. 相似文献