MIS 5 sea-level markers and regional uplifting in the Strait of Gibraltar (North of Morocco)

Abstract

This study investigates the morpho-sedimentary evidence of two highstands registered and dated during MIS 5 stage by U-series dating in the North of Morocco (Strait of Gibraltar). Bioerosive notch and mixed siliciclastic and carbonate deposits, high energy beaches with algal bioherms, were formed in coastal environments during MIS 5a. A sea-level altitude of +10 m asl was inferred for this substage. The record of MIS 5e-2 substage is less complete, consisting in upper foreshore and storm deposits located some meters above the sea-level (+13-15 m asl). A tectonic uplift rate of ~0.1 mm/yr has been estimated for the last 130 ky. This data is consistent with models of coastal uplifts elaborated for the Gibraltar Strait.

Este trabajo analiza las evidencias morfosedimentarias de dos altas paradas del nivel marino datadas en el MIS 5 mediante series de U en el Norte de Marruecos. Durante el MIS 5a se formaron socaves bioerosivos (notches) y facies de playas de alta energía constituidas por depósitos mixtos siliciclástico-carbonatados. Una altura de 10 m snm ha sido estimada para esta etapa. El registro del MIS 5e-2 es menos completo, constituidos por depósitos de foreshore y de tormenta formados varios metros sobre el nivel del mar (+13-15 m snm). Se ha deducido una tasa de elevación tectónica de 0.1 mm/año para los últimos 130 ka. Estos datos son consistentes con los modelos previos de levantamiento tectónico elaborados para el Estrecho de Gibraltar.