Our Research Project:
Magmatism in the eastern Northern Volcanic Zone of the Andes: Processes and timescales in a continental rear-arc setting
The goal of our research is to investigate magmatic processes in the Northern Volcanic Zone (NVZ) of the South American Andes, particularly in the far eastern region of the arc, called the rear-arc (Figure 1). These volcanoes are to the east of the main arc, and are therefore expected to have a a unique geochemical signature. This signature has been documented in other arcs like Kamchatka , Alaska [2,3], Central America [4, 5] and the Cascades . Comprehensive studies of volcanoes in Ecuador also show that the composition of lavas changes systematically from west to east across the volcanic arc [7, 8, 9]. The volcanoes that we are going to study during our expedition are El Reventador, Sumaco, Pan de Azucar and Yanaurcu.
Of particular interest to this study are El Reventador and Sumaco volcanoes, partially because they have contrasting geochemical characteristics, but also because El Reventador has been active since November 2002, after a repose time of 26 years . Sumaco volcano erupted most recently in 1933  and is currently inactive; however it is frequently used to illustrate the alkaline nature of NVZ rear-arc lavas [7, 8, 9]. The NVZ is ideal for this study because it is similar in many ways to other well-studied arcs, yet it exhibits characteristics that are unique to the NVZ.
This research is important because we have the opportunity to learn about the processes that mark the transition from dominantly subduction-influenced melting to the regime of MORB-type petrogenesis in South America. In addition to the primary objective, we will examine timescales of magma ascent and degassing in an active, calc-alkaline rear-arc volcano (El Reventador), which is important for constraining the timescales of magmagenesis in the rear-arc region. Our extensive data set will be used to test existing models of rear-arc magmatism, while developing new models that can be applied to future arc research.