Resolving problems with the origin of Las Canadas caldera (Tenerife, Canary Islands): Los Roques de Garcia Formation - Part of a major debris avalanche or an in situ, stratified, edifice-building succession?

Las Canadas caldera complex, on Tenerife, Canary Islands, truncated the construction of Las Canadas edifice, a central composite volcanic complex formed after a main period of basaltic shield construction. The origin of the present Las Canadas caldera complex is still a matter of considerable debate between two contrasting hypotheses, vertical (caldera forming) or lateral (landslide) collapse. However, there is increasing evidence that a long history of explosive phonolitic volcanism, including several caldera episodes, characterized the construction of Las Canadas edifice. Los Roques de Garcia forms a large spur that divides the Las Canadas caldera complex into two morphological depressions. The sequence of rocks exposed along the spur consists of several formations that from base to top include: Los Roques de Garcia Formation, Los Azulejos Formation, and the lower part of the Ucanca Formation. Los Roques de Garcia Formation occupies the main part of Los Roques de Garcia spur and includes proximal facies of pyroclastic (Lower Member) and sedimentary (epiclastic) (Upper Member) deposits, predominantly breccias, all of which are intruded by a dense network of phonolitic dikes and necks.