To capture and describe the temporal and spatial evolution of magmatic systems, both within volcanic fields and at individual volcanoes, we require new methods and techniques involving many disciplines, including geochemistry, petrology, volcanology, geophysics, and numerical modeling. Temporal and spatial variations in magma evolution reflect a variety of processes, including changing mantle sources, crustal interactions, magma ascent dynamics, pathways, and storage. How do magmas move, through percolation or fracture propagation? What are the rates of magma ascent? How do melts avoid trapping by ductile upper crustal mush zones? Does the chemical stratigraphy of the crystal cargo, including the microlites, provide information about the history of the melt phase, or are crystals dominantly of antecrystic origin? Do magmatic volatiles drive magma ascent, and to what degree do they influence ascent rates and eruptive style? How reliable are melt inclusions in recording the volatile evolution of these melts from source to surface? How do along- or across-arc variations in magma geochemistry provide insights into changing mantle source region dynamics and crustal processing? We invite studies from all tectonic settings (ocean ridges, ocean islands, subduction zones, back-arc basins, petit-spots, intracontinental rifts, monogenetic volcanic fields) that utilize geochemistry and petrology to investigate temporal and/or spatial changes in magmatic systems to improve our understanding of magma sources and magma transport within volcanoes or volcanic fields. We particularly encourage cross-disciplinary studies and those that can provide constraints on how these variations relate to an understanding of volcanic and tectonic processes.

This session will be co-located in the Asia-Pacific, Europe/Africa and Americas regions, with one live session in each region, available to the other two regions as recordings. Each region will schedule twelve 12+3-minute recorded live oral presentation slots including live Q&A, followed by a recorded 1-hour live panel discussion. Depending on the number of submissions, there will also be the opportunity for elightening poster presentations. The oral sessions will run over 1.5 days (7-9 December, depending on the time zone), with the remainder of the meeting 9-11 December available for poster viewing and online Q&A within and across regions. Depending on the overall feedback, this session may form the basis for a special published volume to be prepared during 2021.

Invited/proposed presenters may be attending in person at centralized venues in remote locations, or fully virtual (e.g. through Zoom).