Algarve ; Boulder ; Coastal environment ; Eighteenth Century ; Hydrodynamics ; Modelling ; Palaeogeography ; Portugal ; Sediment transport ; Tsunami
A remarkable accumulation of marine boulders located above the present spring tide level has occurred in 2 coastal lowlands of the Algarve (Portugal). The spreads of boulders extend several hundred meters inland and well beyond the present landward
limit of storm activity. The marine origin of the boulders is demonstrated by well-developed macro-bioerosion sculpturing and in situ skeletal remains of endolithic shallow marine bivalves. The good state preservation of the fossils within the boulders
indicates that abrasion during transport and redeposition was not significant. The AA. envisage boulder deposition as having taken place during the Lisbon tsunami of AD 1755. The AA. use numerical hydrodynamic modeling of tsunami (and storm) waves to test
the observational data on boulder dimensions (density, size, distribution) on the most likely processes of sediment deposition. This work demonstrates the effectiveness of the study of boulder deposits in tsunami reconstruction.
Aerial photography ; Alluvial cone ; Arid area ; Base level ; Boulder ; Dead Sea ; Digital elevation model ; Drainage ; Erosion ; Israel ; Longitudinal section ; Photogrammetry ; Watershed
, on its incision. Longitudinal profiles of the fan-delta and of its entrenched channel were measured in the field. Sedimentary facies changes (fluviatile, shallow lacustrine and beach) were followed along exposures. The existence of large boulders provided
an opportunity to examine the uncertain role of armouring and boulder flux on incision. The field study was combined with digital elevation models (DEMs) that were extracted from pairs of overlapping aerial photos. Maps of erosion and deposition were prepared
Boulder ; Comparative study ; Debris flow ; Experimentation ; Glacial surge ; Model ; Natural hazards ; Norway ; Numerical model ; Rheology
, the presence of large boulders and the higher normal pressure inside the natural debris flow requires the introduction of a novel rheological model that distinguishes between mud-to–clast supported material.
Three exposure ages in the range 80-90 ka, obtained from large dolerite boulders, indicate landslide movement during the last interglacial period; as the deposits show no evidence of movement since first accumulating the deposits must have formed
The changing geography of violence in Russia's North Caucasus, 1999-2011 : regional trends and local dynamics in Dagestan, Ingushetia, and Kabardino-Balkaria : Violence and armed conflicts in the Caucasus
2011
[b1] Institute of Behavioral Science and Dept. of Geography, Univ. of Colorado, Boulder, Etats-Unis
flutes is enriched in δ18O relative to overlying glacier ice and debris-rich basal ice. These properties are interpreted to reflect the formation of flutes by the squeezing of till into basal cavities associated with boulders beneath warm-based ice
Les AA. analysent le développement économique, la dépendance à l'égard des ressources et le bien-être socio-économique des villes minières de Kalgoorlie-Boulder, de Port Hedland et de Karratha-Dampier dans l'Ouest de l'Australie. Ils détaillent les