SEDIMENTARY RECORDS OF HIGH ENERGY EVENTS, EXAMPLES OF THE ATLANTIC COAST OF RABAT-SKHIRAT (MOROCCO)

摘要

Holocene high energy deposits have been identified on the coastline near Rabat-Skhirat ( NW of Morocco). At El Harhoura, the massif of Pleistocene calcarenite is topped by a 2 m thick sand formation. This formation is onlap on residual silty clay deposit, and it consists of a succession of massif sandy deposits, incorporating large boulders. The successive unconsolidated units attest of event deposits caused by storms or by a tsunami. The C-14 age of this Holocene formation is bracketed between 9,700 and 2,300 cal. BP. At Skhirat, the morphology of the coastal ridge, the sedimentary structures and the grain-size reveal a prevailing storm dynamic. The C-14 dating bracketed its formation between 8,000 and 4,000 cal. BP. Along the Skhirat coastal ridge, the beach rock incorporates irregularly clustered mussels and pebbles at its base, as well as several generations of megaboulders. These elements also signed high energy deposits.