Passive magmatism on Earth and Earth-like planets

Abstract

Magmatism has occurred throughout Earth’s history. From the early Earth to the modern plate-tectonic Earth, the amount of magmatism has varied, but it has always occurred on multiple scales, in various tectonic environments and at various depths in the crust and mantle. Magma compositions also vary. In this paper, we argue that the mechanism of magma emplacement has generally been passive at all stages of Earth evolution. We conclude that most magmatism related to subduction, rifting, mid-oceanic spreading, flood basalts and large igneous provinces and related to mantle upwellings, magma underplating, slab windows, orogenic collisions as well as Archean TTG formation are predominantly passive from the lithosphere-scale to the crystal-scale. Our results weigh against the view that magmatism drives plate motions. Most of the magmatism on other Earth-like planets is also passive regardless of the tectonic environments.