The view from the summit of Uturuncu in Bolivia, looking across the Altiplano-Puna Volcanic Complex. What lies underneath the surface is one of the most volcanically-productive places on Earth. Image: Léo Guellec / Flickr. Geology is full of questions -- that is why it is such a vibrant science. There are so many questions about how the processes that make and destroy rocks on this planet work and, in many cases, we've only scratched the surface (literally and figuratively). Being a volcanologist/petrologist, I am especially interested in questions about the source of magma and where it is stored in the crust -- tricky things to quantify because all our evidence is circumstantial. We have a good idea of the general sources of magma in different tectonic settings:
At mid-ocean ridges and hotspots, magma is formed by upwelling mantle material that melts due to dropping pressure (adiabatic melting)
At subduction zones ...
