A review of speleothems as archives for paleofire proxies, with Australian case studies
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Date
2023-03-22
Journal Title
Journal ISSN
Volume Title
Publisher
American Geophysical Union
Abstract
Wildfires affect 40% of the earth's terrestrial biome, but much of our knowledge of wildfire activity is limited to the satellite era. Improved understanding of past fires is necessary to better forecast how fire regimes might change with future climate change, to understand ecosystem resilience to fire, and to improve data-model comparisons. Environmental proxy archives can extend our knowledge of past fire activity. Speleothems, naturally occurring cave formations, are widely used in paleoenvironmental research as they are absolutely dateable, occur on every ice-free continent, and include multiple proxies. Recently, speleothems have been shown to record past fire events (Argiriadis et al., 2019, https://doi.org/10.1021/acs.analchem.9b00767; McDonough et al., 2022, https://doi.org/10.1016/j.gca.2022.03.020; Homann et al., 2022, https://doi.org/10.1038/s41467-022-34950-x). Here we present a review of this emerging application in speleothem paleoenvironmental science. We give a concise overview of fire regimes and common paleofire proxies, describe past attempts to use stalagmites to investigate paleofire, and describe the physical basis through which speleothems can record past fires. We then describe the ideal speleothem sample for paleofire research and offer a summary of applicable laboratory and statistical methods. Finally, we present four case studies from southwest Australia which: (a) explore the geochemistry of ash leachates, (b) detail how sulfate isotopes may be a proxy for post fire ecological recovery, (c) demonstrate how a catastrophic paleofire was linked to changes in climate and land management, and (d) investigate whether deep caves can record past fire events. We conclude the paper by outlining future research directions for paleofire applications. © 2023 The Authors. Open Access CC-By-NC Licence
Description
Keywords
Fires, Caves, Australia, Data, Climates, Geochemistry, Hazards, Earth planet, Ecosystems, Statistics
Citation
Campbell, M., McDonough, L., Treble, P. C., Baker, A., Kosarac, N., Coleborn, K., Wynn, P. M., & Schmitt, A. K. (2023). A review of speleothems as archives for paleofire proxies, with Australian case studies. Reviews of Geophysics, 61(2), e2022RG000790. doi:10.1029/2022RG000790