QUATERNARY PALEOSEA-LEVELS IN CAPE VERDE ARCHIPELAGO

The aim of this work is to analyse the connections between vertical sea-level changes and horizontal displacements of physical and ecophysical sea-surficial conditions between the Atlantic tropical region, and the Mediterranean basin during the Quaternary, using the record of raised marine terraces in Cape Verde Archipelago.

These volcanic islands are located in the Central Atlantic area (17º12’-14º48’N, 25º28’-22º45’W), 450 km off the western African coast and 2000 km east of the Mid-Atlantic Ridge, in the pathway of the warm North Equatorial and Guinea currents.

The flat, low-relief Sal Island is particularly suitable for this study owing to the absence of vegetal cover, and its place at the eastern flank of the archipelago that faces the trade winds. The most complete marine sequences comprises seventeen terraces at elevations between 57 m (asl) and 0m.

Isotopic and paleomagnetic data, coupled with detailed mapping, suggest that at least ten of the raised marine terraces were deposited during interglacial or interestadial periods in the last 800 Kyr. Warm fauna (Strombus bubonius, Nerita senegalensis, Cantharus viverratus, etc.), the so called “Senegalese”, is common in all marine terraces. This fact points to the Cape Verde Archipelago as a main source region of “Senegalese” fauna that entered the Mediterranean Sea during some interglacials and particularly OIS 5e, instead of the Gulf of Guinea where no fossil marine terraces bearing this warm fauna have been cited so far.

Financial Support.- MCYT Projects, BTE 2002, 1065 and 1691