Geoheritage conservation in the Cabo Verde Archipelago: An exceptional juxtaposition of last interglacial beach deposits and deep-sea MORB pillow lavas uplifted during the Cenozoic, on Maio Island

The palaeontological, geomorphological and geological heritage of the Macaronesian archipelagos is outstanding in both diversity and relevance. Some of these volcanic oceanic islands already possess geosites and palaeosites classified as of noteworthy international relevance. In contrast with the Azores and Canaries archipelagos that have state-of-the-art inventories, such an endeavour has not yet been initiated under a systematic framework in the Cabo Verde Archipelago. This study is a first effort to provide a quantitative assessment for the geoheritage relevance of Maio Island (Cabo Verde). Here, we report a unique outcrop of national relevance, where Cretaceous Mid-Ocean Ridge Basalts (MORB) initially formed on the sea floor and subsequently uplifted by ∼6 km, being exposed onshore on the southern and eastern coast of Maio Island. Incidentally, this piece of oceanic crust nowadays occurs side-by-side with abutting fossiliferous sediments from the warmest interval of the last interglacial period (Late Pleistocene, Marine Isotopic Substage 5e – MIS 5e), exposed up to 2 m above present sea level. Following a geoconservation framework, we propose that, along with other geo- and palaeosites from Maio currently under study, this MORB-MIS 5e geosite, located at Pedrinha da Areia bay, should be included in a future tourist “Fossil Route” to be developed on this island, offering clear economic benefits for the local tourist companies and promoting the sustainable use of the island's geoheritage.