Magma dynamics of the phonolitic Diego Hernandez Formation, Tenerife, Canary Islands

The Diego Hernandez Formation (DHF; 600-196 ka) represents the products of the most recent complete cycle of phonolitic explosive volcanism on Tenerife (Canary Islands, Spain). Two distinct phonolite lineages have persisted, or have been regenerated, throughout the history of the DHF. During any one eruption a single phonolite type dominates, but detailed geochemical investigations show that both magmas did exist simultaneously, for example, in the Fasnia Member.; In this dissertation, Chapter 1 describes laser ablation ICP-MS methods developed to analyze in situ trace element contents in pumices and minerals from DHF deposits, data from which are presented in other chapters. Chapter 2 is summary of DHF stratigraphy, geochronology, and physical volcanological interpretation of the DHF that provides context for the geochemistry to follow. Chapter 3 is a detailed study of the geochemistry of the Fasnia Member in which the chemical heterogeneity of whole rocks and glasses are described. Chapters 4 and 5 describe the different clinopyroxene and titanite compositions, respectively, found in the Fasnia and their importance in understanding Fasnia magmatism. Chapter 6 describes geochemical relationships between the DHF chemostratigraphic units and provides an interpretation of magmatic events throughout DHF time relative to the geochemistry.