Geochemical evolution of large-volume silicic magmas from the Afro-Arabian Large Igneous Province

Large volcanic eruptions are perhaps the most destructive force in nature yet the mechanisms by which they are formed and erupted are still under debate. Magmas, which are mixtures of molten rock, crystals, and gas that form beneath the surface, record the depth and processes by which they form in the erupted products. Silicic magmas, whose eruptions are particularly violent because of their higher viscosities, are formed through a combination of complex processes such as the incorporation of rock surrounding the magma chamber and the addition of new magma, all of which affect their geochemical evolution and final composition. Large igneous provinces (LIPs) are the site of short-lived, high-rate, large-volume eruptive episodes that are among the most catastrophic events on Earth. The Afro-Arabian LIP, located in Yemen and East Africa, preserves voluminous (up to ~3100 km³ for individual eruptions) and laterally extensive (up to 30,000 km²) volcanic deposits that erupted 31 to 27 million years ago. These are among the largest known eruptions of silicic magma on Earth and the largest of these eruptions occurred within a timespan of 14,000 to 77,000 years. This raises the question as to how large volumes of silicic magma can be generated and erupted in such geologically short periods of time. This study helps to resolve this by tracking the geochemical evolution of these magmas prior to and during eruption and constraining the timing of events to understand the processes that lead to catastrophic volcanic eruptions.