Tatiana Izquierdo

Spreading and potential instability of Teide volcano, Tenerife, Canary Islands

[1]xa0We analyze the role of low-strength materials in the potential structural instability related to volcano spreading at the active Teide stratovolcano (Tenerife, Canary Islands). To study the low-strength materials we took advantage of a network of large tunnels within the volcano, excavated for water supply, which allows the in situ inspection and reconstruction of both volcano and substratum structure. We identified two factors which are potentially important to Teides instability: 1) a dipping low-strength substratum breccia layer; and 2) a hydrothermally-altered weak core inside the volcano. Despite we do not find clear structural evidence for volcano substratum spreading, both Teide topographic shape and the summit faulting are features similar to those accepted as examples of volcano flank spreading over a weak core. The detected asymmetric deformation of the edifice makes the north flank of Teide a strong candidate for a potential failure.

Holocene palaeoenvironmental evolution of Saltés Island (Tinto and Odiel estuary, SW Spain) during the Roman period (1st century BC–5th century AD)

A multidisciplinary analysis of Holocene sediments from Saltés Island (Tinto-Odiel estuary, SW Spain) has allowed to differentiate eigth sedimentary facies, according to their textural characteristics, internal structure, paleontology and archaeological content. Its interpretation and the chronological datings carried out reconstruct a transition from a sandy tidal plain to a final occupation by a Roman salting (cetaria) between the 1st century BC to 5th century A. This evolution includes the deposit of washover fans derived from high-energy events between the 1st century BC to 3th century AD. The integration of these new data with others from previous research has allowed partially complete the palaeoenviromental reconstruction of the marine domain of the Tinto-Odiel estuary.ResumenEl análisis multidisciplinar de sedimentos holocenos procedentes de la isla Saltés, situada en el estuario de los ríos Tinto y Odiel (SO de España), ha permitido diferenciar ocho facies sedimentarias, de acuerdo a sus características texturales, estructura interna, contenido paleontológico y restos arqueológicos presentes. Su interpretación y las dataciones cronológicas efectuadas han permitido reconstruir una transición desde una llanura mareal arenosa a la ocupación final de la zona por una factoría romana de salazones (cetaria) entre los siglos I BC y V AD. Esta evolución incluye el depósito de washover fans derivados de la acción de eventos de alta energía entre los siglos I BC y III AD. La integración de estos nuevos datos con otros procedentes de investigaciones previas ha permitido completar parcialmente la reconstrucción paleoambiental del dominio marino del estuario de los ríos Tinto y Odiel.