The Experts below are selected from a list of 1380 Experts worldwide ranked by ideXlab platform
Bernadette Tessier - One of the best experts on this subject based on the ideXlab platform.
-
internal architecture and evolution of Bioclastic beach ridges in a megatidal chenier plain field data and wave flume experiment
Sedimentology, 2013Co-Authors: Pierre Weill, Dominique Mouaze, Bernadette TessierAbstract:Beach ridges in macrotidal environments experience strong multi-annual to multi-decennial fluctuations of tidal inundation. The duration of tide flooding directly controls the duration of Sediment reworking by waves, and thus the ridge dynamics. Flume modelling was used to investigate the impact of low-frequency tidal cycles on beach ridge evolution and internal architecture. The experiment was performed using natural Bioclastic Sediment, constant wave parameters and low-frequency variations of the mean water level. The morphological response of the beach ridge to water level fluctuations and the preservation of Sedimentary structures were monitored by using side-view and plan-view photographs. Results were compared with the internal architecture of modern Bioclastic beach ridges in a macrotidal chenier plain (Mont St. Michel Bay, France) surveyed with ground-penetrating radar. The experimentally obtained morphologies and internal structures matched those observed in the field, and the three ridge development stages identified in ground-penetrating radar profiles (early transgressive, late transgressive and progradational) were modelled successfully. Flume experiments indicate that flat Bioclastic shapes play a key role in Sediment sorting in the breaker zone, and in Sediment layering in the beach and washover fans. Water level controls washover geometry, beach ridge evolution and internal structure. Low water levels allow beach ridge stabilization and Sediment accumulation lower on tidal flats. During subsequent water level rise, accumulated Sediment becomes available for deposition of new washover units and for bayward extension of the beach ridges. In the field, low-frequency water level fluctuations are related to the 4·4 year and 18·6 year tidal cycles. Experimental results suggest that these cycles may represent the underlying factor in the evolution of the macrotidal chenier coast at the multi-decadal to centennial time scale.
Pierre Weill - One of the best experts on this subject based on the ideXlab platform.
-
internal architecture and evolution of Bioclastic beach ridges in a megatidal chenier plain field data and wave flume experiment
Sedimentology, 2013Co-Authors: Pierre Weill, Dominique Mouaze, Bernadette TessierAbstract:Beach ridges in macrotidal environments experience strong multi-annual to multi-decennial fluctuations of tidal inundation. The duration of tide flooding directly controls the duration of Sediment reworking by waves, and thus the ridge dynamics. Flume modelling was used to investigate the impact of low-frequency tidal cycles on beach ridge evolution and internal architecture. The experiment was performed using natural Bioclastic Sediment, constant wave parameters and low-frequency variations of the mean water level. The morphological response of the beach ridge to water level fluctuations and the preservation of Sedimentary structures were monitored by using side-view and plan-view photographs. Results were compared with the internal architecture of modern Bioclastic beach ridges in a macrotidal chenier plain (Mont St. Michel Bay, France) surveyed with ground-penetrating radar. The experimentally obtained morphologies and internal structures matched those observed in the field, and the three ridge development stages identified in ground-penetrating radar profiles (early transgressive, late transgressive and progradational) were modelled successfully. Flume experiments indicate that flat Bioclastic shapes play a key role in Sediment sorting in the breaker zone, and in Sediment layering in the beach and washover fans. Water level controls washover geometry, beach ridge evolution and internal structure. Low water levels allow beach ridge stabilization and Sediment accumulation lower on tidal flats. During subsequent water level rise, accumulated Sediment becomes available for deposition of new washover units and for bayward extension of the beach ridges. In the field, low-frequency water level fluctuations are related to the 4·4 year and 18·6 year tidal cycles. Experimental results suggest that these cycles may represent the underlying factor in the evolution of the macrotidal chenier coast at the multi-decadal to centennial time scale.
Dominique Mouaze - One of the best experts on this subject based on the ideXlab platform.
-
internal architecture and evolution of Bioclastic beach ridges in a megatidal chenier plain field data and wave flume experiment
Sedimentology, 2013Co-Authors: Pierre Weill, Dominique Mouaze, Bernadette TessierAbstract:Beach ridges in macrotidal environments experience strong multi-annual to multi-decennial fluctuations of tidal inundation. The duration of tide flooding directly controls the duration of Sediment reworking by waves, and thus the ridge dynamics. Flume modelling was used to investigate the impact of low-frequency tidal cycles on beach ridge evolution and internal architecture. The experiment was performed using natural Bioclastic Sediment, constant wave parameters and low-frequency variations of the mean water level. The morphological response of the beach ridge to water level fluctuations and the preservation of Sedimentary structures were monitored by using side-view and plan-view photographs. Results were compared with the internal architecture of modern Bioclastic beach ridges in a macrotidal chenier plain (Mont St. Michel Bay, France) surveyed with ground-penetrating radar. The experimentally obtained morphologies and internal structures matched those observed in the field, and the three ridge development stages identified in ground-penetrating radar profiles (early transgressive, late transgressive and progradational) were modelled successfully. Flume experiments indicate that flat Bioclastic shapes play a key role in Sediment sorting in the breaker zone, and in Sediment layering in the beach and washover fans. Water level controls washover geometry, beach ridge evolution and internal structure. Low water levels allow beach ridge stabilization and Sediment accumulation lower on tidal flats. During subsequent water level rise, accumulated Sediment becomes available for deposition of new washover units and for bayward extension of the beach ridges. In the field, low-frequency water level fluctuations are related to the 4·4 year and 18·6 year tidal cycles. Experimental results suggest that these cycles may represent the underlying factor in the evolution of the macrotidal chenier coast at the multi-decadal to centennial time scale.
Adam Vecsei - One of the best experts on this subject based on the ideXlab platform.
-
Bioclastic Sediment lobes on a supply dominated upper cretaceous carbonate platform margin montagna della maiella italy
Sedimentology, 1998Co-Authors: Adam VecseiAbstract:A thick Bioclastic Sediment wedge was deposited on the slope of the Maiella carbonate platform margin in the Late Campanian to Late Maastrichtian. The wedge consists of lobate depositional units (laterally and vertically convex structures). The complex internal geometries of the lobes combine characteristics of unidirectional sandwaves and the alternating point-sources of deltas. Excellent outcrop permits a detailed documentation and discussion of the depositional processes. The Sediment wedge constitutes a supersequence, which prograded along the platform margin as a result of high Sediment supply and forced regression. Within the supersequence, a hierarchy of higher-order stratigraphic units (sequence sets and sequences) are developed. The individual Bioclastic Sediment lobes are interpreted as systems tracts and parasequences of the sequences within the sequence sets.
O H Walliser - One of the best experts on this subject based on the ideXlab platform.
-
controls of mud mound formation the early devonian kess kess carbonates of the hamar laghdad antiatlas morocco
International Journal of Earth Sciences, 1992Co-Authors: Thomas C Brachert, Werner Buggisch, Erik Flugel, H M Hussner, Michael M Joachimski, F Tourneur, O H WalliserAbstract:The origin and development of Early Devonian (late Pragian to late Zlichovian; predominantly uppermost Zlichovian as indicated by conodont faunas) mud mounds of the Hamar Laghdad area in the eastern Antiatlas, Morocco, are controlled by extrinsic and intrinsic factors. Extrinsic factors include the existence of a paleohigh (Lochkovian volcaniclastics), unidirectional currents and repeated storm events as well as sea level fluctuations. Intrinsic, biologically induced factors are the preferred growth of organisms on the top and the flanks of the mounds because of more favourable ecological conditions, and a rapid synSedimentary lithification of the steep mound flanks by interskeletal cementation of auloporid tabulate corals. The mounds developed in an epicontinental basin below the wave base but within the range of storms. The formation of the mounds started within the uppermost part of the bedded crinoid facies of the Kess-Kess Formation with the hydrological accumulation of a Bioclastic pile. This elevation became settled by crinoids and high-diverse tabulate corals producing Bioclastic Sediment. Binding activities of the organisms were missing, calcareous algae and stromatoporoids are completely absent. Baffling by thamnoporid tabulate corals might have occurred locally but was not important for the development of the mounds. Steep slopes to the north and less steep slopes to the south may be the result of north-northwest to south-southeast trending currents, derived from orientation patterns of orthocone nautiloids in the uppermost beds of the Kess-Kess Formation. A synSedimentary cementation of the flanks, possibly triggered by submarine interskeletal cementation of patchily distributed auloporid colonies, protected the Bioclastic Sediment against redistribution by frequent storms (indicated by densely spaced eventstone intervals and partly also by the common >>Stromatactis<<-like structures within the mound facies). Accumulation of more parautochthonous Bioclastic Sediment within the mounds as compared to the intermound area, therefore, is caused by a self-sustaining system of hydrologic piling of Sediment triggered by storms, preferred settlement of organisms upon these piles, producing Bioclastic Sediment and coeval biocementation of the growing mound flanks. This model differs from existing mud mound models in the lack or only minor significance of binding and baffling, in the lack of mound facies sequences and in the greater importance of extrinsic control factors.