Quaternary explosive volcanism of the Cape Verde Archipelago: On- and offshore tephrostratigraphy

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28 gravity cores up to 9 m long, collected during cruise M80/3 around and across the Cape Verde Archipelago, contain a total of 205 ash layers that document highly explosive eruptions from several of the islands since the late Pleistocene. This project aims to correlate ash layers between cores and with tephras on land in order to establish a tephrostratigraphic framework supported by absolute age dating. Geochemical, petrological and volcanological characterization of these mafic, felsic, and occasionally compositionally zoned, highly alkalic tephras will then be used to constrain temporal and spatial changes in eruption processes, magnitudes and frequencies as well as conditions of magmatic evolution. A special focus will be on the generation of the apparently abundant mafic Plinian eruptions. Comparison of our results on late Quarternary volcanism with data from a parallel project on seamounts and island flanks representing earlier growth stages will improve understanding of ocean island evolution. The stratigraphic framework of marker beds will also constrain ages and rates of other geological events (turbidity currents from island-flank instability, input of Saharan dust, diagenesis) as well as marine plankton evolution.