Geodynamic controls on magmatic arc migration and quiescence

Abstract

Reconfigurations of magmatic arcs through time have been recognized since pioneering works, describing inland and trenchward arc migrations or magmatic shut-off lasting for several millions of years. These modifications present variable magnitudes and rates of arc migration and magmatic broadening, and different arc quiescence time spans. The time-space behavior of magmatic arcs has been attributed to a diversity of geodynamic processes acting at convergent margins largely associated with modifications in the upper-plate or changes in plate kinematics. Identifying a geodynamic process responsible for a particular spatiotemporal arc history from the geological record is not straightforward. This task is further complicated where more than one process influencing arc position acted in concert. To assess these issues, it is essential to have a deep understanding of how each process influences the space-time arc behavior and modifies the geological context. To date, a joint comparison highlighting similarities and differences in how these phenomena impact arc dynamics and the associated geological framework is still missing from the literature. In this study, we provide a state-of-the-art synthesis of processes controlling arc migration and quiescence. Then, we extract diagnostic elements from the literature to build a synthetic table to aid in the task of discerning a dominant geodynamic process from the geological record. In this task, we considered the first-order characteristics of the space-time arc evolution and diagnostic features of the geological context associated with each geodynamic process. Finally, this synthesis stresses that the combination of both perspectives, understanding the space-time arc pattern and the associated geological framework, provides the best approach to unravel a dominant process controlling arc migration and shut-off.