Biased witnesses: crystal thermal records may give conflicting accounts of magma cooling

Culha, C., Keller, T. and Suckale, J. (2022) Biased witnesses: crystal thermal records may give conflicting accounts of magma cooling. Journal of Geophysical Research: Solid Earth, 127(5), e2021JB023530. (doi: 10.1029/2021JB023530)

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Crystals retain an imprint of the dynamic changes within a magma reservoir and hence contain invaluable information about the evolving conditions inside volcanic plumbing systems. However, instead of telling a single, simple story, they comprise overprinted evidence of numerous processes relating to temperature, pressure and composition that drive crystal precipitation and dissolution in magmatic systems. To decipher these different elements in the story that crystals tell, we attempt to identify the observational signatures of a simple, yet ubiquitous process: crystal precipitation and dissolution during magma cooling. To isolate this process in a complex magmatic system with intricate dynamic feedbacks, we assume that synthetic crystals precipitate and dissolve rapidly in response to deviations from thermodynamic equilibrium. In our crystalline-scale simulations, synthetic crystals drag along the cooler-than-ambient melt in which they precipitated and can drive a temperature-dependent, crystal-driven convection. We analyze the non-dimensional conditions for this coupled convection and record the heterogeneous thermal histories that synthetic crystals in this flow regime experience. We show that many synthetic crystals dissolve, loosing their thermal record of the convection. Based on our findings, we suggest that heterogeneity in the thermal history of crystals is more indicative of local, crystal-scale processes than the overall, system-wide cooling trend.

Item Type:Articles
Additional Information:This work is 693 supported by NSF grant 1744758 awarded to JS. CC acknowledges support from the NSF’s GRFP, Stanford University’s McGee Grant and Stanford University’s Lieberman Fellowship. TK acknowledges support from the Swiss National Science Foundation’s Post doc.Mobility Fellowship 177816.
Keywords:Reactive, crystal-driven convection, crystal records, fluid dynamics, thermodynamics, downwelling.
Glasgow Author(s) Enlighten ID:Keller, Dr Tobias
Authors: Culha, C., Keller, T., and Suckale, J.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:Journal of Geophysical Research: Solid Earth
ISSN (Online):2169-9356
Published Online:20 April 2022
Copyright Holders:Copyright © 2022 The Authors
First Published:First published in Journal of Geophysical Research: Solid Earth 127(5): e2021JB023530
Publisher Policy:Reproduced under a Creative Commons License
Data DOI:10.5281/zenodo.4393097

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