TY - JOUR

T1 - A Review of Speleothems as Archives for Paleofire Proxies, With Australian Case Studies

AU - Campbell, Micheline

AU - McDonough, Liza

AU - Treble, Pauline C.

AU - Baker, Andy

AU - Kosarac, Nevena

AU - Coleborn, Katie

AU - Wynn, Peter M.

AU - Schmitt, Axel K.

PY - 2023/6/30

Y1 - 2023/6/30

N2 - 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.

AB - 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.

KW - BIOGEOSCIENCES

KW - Paleoclimatology and paleoceanography

KW - Isotopic composition and chemistry

KW - GEOCHEMISTRY

KW - Stable isotope geochemistry

KW - Sedimentary geochemistry

KW - Major and trace element geochemistry

KW - ATMOSPHERIC PROCESSES

KW - Paleoclimatology

KW - OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL

KW - Stable isotopes

KW - PALEOCEANOGRAPHY

KW - Speleothems

KW - Commissioned Manuscript

KW - speleothem

KW - paleofire

KW - geochemistry

KW - paleoclimate

KW - stalagmite

U2 - 10.1029/2022rg000790

DO - 10.1029/2022rg000790

M3 - Journal article

VL - 61

JO - Reviews of Geophysics

JF - Reviews of Geophysics

SN - 8755-1209

IS - 2

ER -