Geological Society of London
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Tracers of uplift and subsidence in the Cape Verde archipelago

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journal contribution
posted on 2016-06-21, 12:21 authored by R. Ramalho, G. Helffrich, D.N. Schmidt, D. Vance

Ocean islands are subject to vertical movements through their lifetime and these movements' origins are poorly understood. Tracking island freeboard provides insight into the mechanisms that cause these movements. The Cape Verde archipelago is the result of hotspot volcanism ranging from 26 Ma to the present, and constitutes a structural pile that has preserved a record of the palaeo-positions of mean sea level. These palaeo-markers, both sedimentary and volcanic, are datable and can be used to track the island's history of vertical movements when used in conjunction with a eustatic curve. We have studied the volcanostratigraphy of Cape Verde and mapped the palaeo-marker positions and features, and we provide the sea-level height information that can be estimated through them. Evidence exists for differential uplift histories throughout the archipelago, with substantial uplift in some of the islands synchronous with volcanism. Other islands, in contrast, exhibit evidence for stability or complex uplift–subsidence histories.