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901.
Wilfried B. M. Ten Brinke Margriet M. Schoor Anne M. Sorber Henk J. A. Berendsen 《地球表面变化过程与地形》1998,23(9):809-824
Using aerial photographs and field measurements, sandy overbank deposits formed by the large-magnitude floods of 1993/94 and 1995 were quantified along two branches of the Dutch Rhine river system: the Waal (1993/94 and 1995) and the IJssel (1995). These deposits were laid down intermittently all along the length of these rivers on the top and landward slope of the natural levees, and covered about 4 per cent of the embanked floodplain on the Waal and about 1 per cent on the IJssel. The overbanks and transport mechanism is basically convective by nature. The spatial variability of overbank sedimentation points to the important role played by helicoidal currents in determining overbank deposition. The presence of embankments and training works appears to influence the sand transport to and morphological development of the floodplains along the Dutch Rhine river system. Overbank deposition volumes about equal present estimates of sand transport during a large-magnitude flood. It appears that studies on sand transport in the Dutch Rhine carried out so far underestimate sand transport during floods. © 1998 John Wiley & Sons, Ltd. 相似文献
902.
Asplin Lars Albretsen Jon Johnsen Ingrid Askeland Sandvik Anne Dagrun 《Ocean Dynamics》2020,70(8):1151-1167
Ocean Dynamics - Norway has complicated dynamics in the coastal ocean and in the fjords. In this area is also the largest salmon aquaculture industry in the world. The salmon industry is valuable... 相似文献
903.
All landscapes are subject to stress fields, conditioned by their formation and ongoing tectonic and geomorphic changes. With this ESEX Commentary we wish to stimulate a debate on this invisible but persistent stress control on landforms, processes and materials in geomorphology. We address the legacy of active and passive stress fields, which translates into the concept of ‘tectonic predesign’, in conjunction with a perspective of geomorphic processes being driven by subcritical stresses. These concepts complement each other as ‘subcritical processes’ are controlled by tectonic predesign and in turn modulate the stress fields. This offers new theoretical and practical perspectives on how landscapes evolve, processes form materials and how rocks break easily. © 2018 John Wiley & Sons, Ltd. 相似文献
904.
Marie Grace Pamela G. Faylona Claire E. Lazareth Anne‐Marie Smah Sandrine Caquineau Hugues Boucher Wilfredo P. Ronquillo 《Geoarchaeology》2011,26(6):888-901
Tridacnidae shells, a valuable archive of past environments, are common in the Balobok Rockshelter archaeological site on Sanga‐Sanga Island in the south Philippines. This site was occupied during the mid‐Holocene (ca. 5000–8800 14C yr B.P.), a period of Neolithic cultural expansion in the Philippines. This paper focuses on the preservation of two shell specimens, Hippopus hippopus and Tridacna maxima, unearthed from two mid‐Holocene layers within the rockshelter. The shells' mineralogy and microstructure (prismatic and crossed‐lamellar) were studied using micro‐Fourier transform infrared spectroscopy and scanning electron microscopy to determine if the samples were suitable as paleoenvironmental records. Both shells are still aragonitic but aragonite crystals of both microstructure types are partly dissolved. This dissolution, characteristic of meteoric water alteration, precludes their utility in paleoenvironmental geochemical studies. Nevertheless, these shells are abundant in archaeological sites in the region and may be better preserved in other depositional contexts; more studies on Philippine Tridacnidae shell diagenesis are needed. © 2011 Wiley Periodicals, Inc. 相似文献