203 Old and the New, Long and the Short: Perspectives on Integration of Timescales of Magmatic Processes: Special Session Related to MGPV Awards to Madison Myers and Anita Grunder
We encourage papers that challenge and give insights into the interplay between timescales, methodologies, and processes to build a cohesive understanding of the lifespan, evolution, storage, and eruption of magma, from plutonic to volcanic systems.
Tuesday, 21 October 2025
1:30 PM - 5:30 PM
HBGCC, 216AB
Petrological Constraints on Thermal Histories of Magma Storage in the Crust: Moving Beyond the “Cold” and “Warm” Storage Dichotomy
Paper number: 203-9
Program: Technical Sessions
Time: 3:45 PM – 4:00 PM
Authors
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Adam KentOregon State University, Corvallis, OR
Abstract
Understanding magmatic processes and forecasting eruptions requires understanding the physical behavior of magmas while they are stored and transported within the Earth’s crust. The mobility of magmas is fundamentally tied to their viscosity. While in detail controls on magma viscosity are complex, with effects from crystals, bubbles, temperature, and composition, the relationship between crystallinity and magma viscosity (and therefore mobility) is strong, and the rheological transition between liquid-dominated and mobile and crystal-dominated and relatively immobile occurs at similar temperatures for most silicic magmas. Therefore, magma storage temperature is a useful proxy for magma crystallinity and therefore mobility. We synthesize petrological and other constraints on the thermal histories that magmas experience during crustal storage. We also bring a common conceptual framework to the recent debate between “cold” and “warm” magma storage models which allows us to present a more coherent synthesis of magma storage conditions. Despite the popularity of the cold vs. warm storage paradigm, there is evidence supporting both cold and warm storage between different systems and over time within the same system. Nevertheless, when a common framework of terminology is applied, the majority of studies (~75%) suggest that long-term magma storage occurred predominantly in crystal-dominated but likely supersolidus conditions. This shows that most silicic crustal magmatic systems spend most of their time in a rheologically immobile state, but that this is not uniform across all systems at all times. Furthermore, mafic systems and some large dacitic systems may spend a higher proportion of time in hotter, more mobile conditions. This recognition of dominantly immobile but variable storage conditions allows us to move beyond a simple dichotomy and to ask more interesting questions about how these variations in magma storage occur and evolve.
Geological Society of America Abstracts with Programs. Vol. 57, No. 6
doi: 10.1130/abs/2025AM-414252
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