%0 Journal Article %T Ca isotopes record rapid crystal growth in volcanic and subvolcanic systems %+ Institut de Physique du Globe de Paris (IPGP (UMR_7154)) %+ Department of Earth and Planetary Science [UC Berkeley] (EPS) %+ School of Earth Sciences [Bristol] %+ University of Oregon [Eugene] %A Antonelli, Michael, A %A Mittal, Tushar %A Mccarthy, Anders %A Tripoli, Barbara %A Watkins, James, M %A Depaolo, Donald, J. %Z National Science Foundation (NSF)EAR100500Natural Sciences and Engineering Research Council of Canada National Science Foundation (NSF)EAR1615203 %< avec comité de lecture %@ 0027-8424 %J Proceedings of the National Academy of Sciences of the United States of America %I National Academy of Sciences %V 116 %N 41 %P 20315-20321 %8 2019 %D 2019 %R 10.1073/pnas.1908921116 %K crystal growth %K timescales %K Ca isotopes %K volcanic eruptions %K magma recharge %Z Sciences of the Universe [physics]/Earth Sciences/VolcanologyJournal articles %X Kinetic calcium isotope effects can be used as growth-rate proxies for volcanic and subvolcanic minerals. Here, we analyze Ca isotopic compositions in experimental and natural samples and confirm that large kinetic effects (>2‰) can occur during magmatic plagioclase crystallization. Experiments confirm theoretical predictions that disequilibrium isotope effects depend mainly on the rates for crystal growth relative to liquid phase Ca diffusivity (R/D). Plagioclase phenocrysts from the 1915 Mount Lassen rhyodacite eruption, the ∼650-y-old Deadman Creek Dome eruption, and several mafic subvolcanic orbicules and plagioclase comb layers from Northern California have disequilibrium Ca isotopic compositions that suggest rapid crystal growth rates (>1 cm/y to 15 cm/y). The Ca isotope results, combined with complementary crystal-size distribution analyses, suggest that magmatic rejuvenation (and eruption) events, as reflected in crystal growth times, can be as short as ∼10−3 y. Although mafic systems are predicted to have shorter magmatic rejuvenation periods, we find similarly short timescales in both mafic and silicic systems. These results are consistent with a growing body of evidence suggesting that dominantly crystalline volcanic magma reservoirs can be rapidly reactivated by the injection of fresh magma prior to eruption. By focusing on a common mineral such as plagioclase, this approach can be applied across all major magmatic compositions, suggesting that Ca isotopes can be used as a tool for investigating the dynamics and timing of volcanic eruptions. %G English %2 https://insu.hal.science/insu-02558381/document %2 https://insu.hal.science/insu-02558381/file/20315.full.pdf %L insu-02558381 %U https://insu.hal.science/insu-02558381 %~ INSU %~ AFRIQ %~ CNRS %~ IPGP %~ USPC %~ UNIV-PARIS