Characteristic features of modern tidal flats in cold regions
Dionne, J.C. (1988). Characteristic features of modern tidal flats in cold regions, in: de Boer, P.L. et al. (Ed.) Tide-influenced sedimentary environments and facies. Extended versions of papers presented at the Symposium on Classic Tidal Deposits, held August 1985 in Utrecht, Netherlands. pp. 301-332 In: de Boer, P.L. et al. (Ed.) (1988). Tide-influenced sedimentary environments and facies. Extended versions of papers presented at the Symposium on Classic Tidal Deposits, held August 1985 in Utrecht, Netherlands. D. Reidel Publishing: Dordrecht. ISBN 90-277-2622-1. ix, 530 pp., more |
| Abstract | Modern tidal flats in cold regions differ significantly in many aspects from those of temperate and warm regions because they are influenced by ice and frost processes. A major sedimentary difference is the occurrence of coarse debris mixed with sand and silt; many tidal flats are even boulder-strewn. Shore ice produces several characteristic sedimentary features such as micro-relief, icepush ridges, grooves and furrows, circular depressions, polished and striated surfaces, skip, drag and roll marks, ribbed grooves, polygonal patterns, monroes, microcraters, and deformations. Under favourable conditions , most ice-made features can be buried or fossilized. Consequently, they could serve as valuable indicators of former environmental conditions of deposition for consolidated tidal deposits. Shore ice also plays an important role in tidal flat development, offering protection during the annual period of increased erosion by waves and currents, and also in controlling the sedimentary budget, for a significant percentage of the volume of fine-grained sediments is transported in-and-out by ice rather than by waves and currents. Frost processes also produce characteristic features and significantly influence the development of tidal flats. However, this aspect remains poorly documented. There exists a real zonation of cold-region tidal flats in relation to latitude. Those in southern areas are little influenced by frost, while those at high latitudes are dominated by frost action and little influenced by ice. In addition, differences are also explained by tidal range, geomorphological setting, nature of sediments, and climatic factors. |
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