Semiquantitative Estimates of Rainfall Variability During the 8.2 kyr Event in California Using Speleothem Calcium Isotope Ratios

Cameron B. de Wet; Andrea M. Erhardt; Warren D. Sharp; Naomi E. Marks; Harold J. Bradbury; Alexandra V. Turchyn; Yiruo Xu; Jessica L. Oster

doi:10.1029/2020GL089154

Semiquantitative Estimates of Rainfall Variability During the 8.2 kyr Event in California Using Speleothem Calcium Isotope Ratios

Cameron B. de Wet
, Andrea M. Erhardt
, Warren D. Sharp
, Naomi E. Marks
, Harold J. Bradbury
, Alexandra V. Turchyn
, Yiruo Xu
, Jessica L. Oster

Earth and Environmental Sciences

Research output: Contribution to journal › Article › peer-review

21 Scopus citations

Abstract

A multiproxy record from a fast-growing stalagmite reveals variable hydroclimate on the California coast across the 8.2 kyr event and a precursor event likely caused by initial drainage of proglacial Lake Agassiz. Using speleothem δ⁴⁴Ca, we develop the first semiquantitative estimates of paleorainfall variability for California through calibration with measurements of the modern climate and cave environment. We find that the magnitude of rainfall variability during the 8.2 kyr event approached the multiyear variability observable in the recent past (1950–2019) and the magnitude of variability during the precursor event likely exceeded this range. Additionally, we observe other instances of multidecadal variability comparable in magnitude to the precursor event during the record. Our work suggests that speleothem calcium isotope ratios are a powerful semiquantitative means to reconstruct paleorainfall, although numerous factors must be assessed in each cave system before applying this approach.

Original language	English
Article number	e2020GL089154
Journal	Geophysical Research Letters
Volume	48
Issue number	3
DOIs	https://doi.org/10.1029/2020GL089154
State	Published - Feb 16 2021

Bibliographical note

Publisher Copyright:
© 2020. American Geophysical Union. All Rights Reserved.

Funding

Funding was provided by the National Science Foundation (AGS\u20101554998) and the National Geographic Society (NGS\u201039815) (to Jessica L. Oster) and the Karst Waters Institute and the Geological Society of America (to Cameron B. de Wet). Calcium isotope analyses were supported through ERC StG 307582 CARBONSINK (to Alexandra V. Turchyn) and NERC NE/R013519/1 (to Harold J. Bradbury). We thank Mike Davies and Bruce Rogers of the Western Cave Conservancy for guidance in the field and the editor, Stacy Carolin, and two other anonymous reviewers for constructive feedback. Data are with the NOAA National Centers for Environmental Information Paleoclimatology Data repository ( https://www.ncdc.noaa.gov/paleo/study/32012 ). This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE\u2010AC52\u201007NA27344. LLNL\u2010JRNL\u2010807062. Funding was provided by the National Science Foundation (AGS-1554998) and the National Geographic Society (NGS-39815) (to Jessica L. Oster) and the Karst Waters Institute and the Geological Society of America (to Cameron B. de Wet). Calcium isotope analyses were supported through ERC StG 307582 CARBONSINK (to Alexandra V. Turchyn) and NERC NE/R013519/1 (to Harold J. Bradbury). We thank Mike Davies and Bruce Rogers of the Western Cave Conservancy for guidance in the field and the editor, Stacy Carolin, and two other anonymous reviewers for constructive feedback. Data are with the NOAA National Centers for Environmental Information Paleoclimatology Data repository (https://www.ncdc.noaa.gov/paleo/study/32012). This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-JRNL-807062.

Funders	Funder number
Geological Society of America
Engineering Research Centers
Karst Waters Institute
Stacy Carolin
European Commission
U.S. Department of Energy Oak Ridge National Laboratory U.S. Department of Energy National Science Foundation National Energy Research Scientific Computing Center
UK Industrial Decarbonization Research and Innovation Centre
U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China	AGS‐1554998
U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China
National Geographic Society	NGS‐39815
National Geographic Society
Lawrence Livermore National Laboratory	DE‐AC52‐07NA27344, LLNL‐JRNL‐807062
Lawrence Livermore National Laboratory
Natural Environment Research Council	NE/R013519/1
Natural Environment Research Council
Seventh Framework Programme	307582
Seventh Framework Programme

Keywords

calcium isotopes
climate whiplash
speleothem
strontium isotopes

ASJC Scopus subject areas

Geophysics
General Earth and Planetary Sciences

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10.1029/2020GL089154

Cite this

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title = "Semiquantitative Estimates of Rainfall Variability During the 8.2 kyr Event in California Using Speleothem Calcium Isotope Ratios",

abstract = "A multiproxy record from a fast-growing stalagmite reveals variable hydroclimate on the California coast across the 8.2 kyr event and a precursor event likely caused by initial drainage of proglacial Lake Agassiz. Using speleothem δ44Ca, we develop the first semiquantitative estimates of paleorainfall variability for California through calibration with measurements of the modern climate and cave environment. We find that the magnitude of rainfall variability during the 8.2 kyr event approached the multiyear variability observable in the recent past (1950–2019) and the magnitude of variability during the precursor event likely exceeded this range. Additionally, we observe other instances of multidecadal variability comparable in magnitude to the precursor event during the record. Our work suggests that speleothem calcium isotope ratios are a powerful semiquantitative means to reconstruct paleorainfall, although numerous factors must be assessed in each cave system before applying this approach.",

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AU - de Wet, Cameron B.

AU - Erhardt, Andrea M.

AU - Sharp, Warren D.

AU - Marks, Naomi E.

AU - Bradbury, Harold J.

AU - Turchyn, Alexandra V.

AU - Xu, Yiruo

AU - Oster, Jessica L.

PY - 2021/2/16

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N2 - A multiproxy record from a fast-growing stalagmite reveals variable hydroclimate on the California coast across the 8.2 kyr event and a precursor event likely caused by initial drainage of proglacial Lake Agassiz. Using speleothem δ44Ca, we develop the first semiquantitative estimates of paleorainfall variability for California through calibration with measurements of the modern climate and cave environment. We find that the magnitude of rainfall variability during the 8.2 kyr event approached the multiyear variability observable in the recent past (1950–2019) and the magnitude of variability during the precursor event likely exceeded this range. Additionally, we observe other instances of multidecadal variability comparable in magnitude to the precursor event during the record. Our work suggests that speleothem calcium isotope ratios are a powerful semiquantitative means to reconstruct paleorainfall, although numerous factors must be assessed in each cave system before applying this approach.

AB - A multiproxy record from a fast-growing stalagmite reveals variable hydroclimate on the California coast across the 8.2 kyr event and a precursor event likely caused by initial drainage of proglacial Lake Agassiz. Using speleothem δ44Ca, we develop the first semiquantitative estimates of paleorainfall variability for California through calibration with measurements of the modern climate and cave environment. We find that the magnitude of rainfall variability during the 8.2 kyr event approached the multiyear variability observable in the recent past (1950–2019) and the magnitude of variability during the precursor event likely exceeded this range. Additionally, we observe other instances of multidecadal variability comparable in magnitude to the precursor event during the record. Our work suggests that speleothem calcium isotope ratios are a powerful semiquantitative means to reconstruct paleorainfall, although numerous factors must be assessed in each cave system before applying this approach.

KW - calcium isotopes

KW - climate whiplash

KW - speleothem

KW - strontium isotopes

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JF - Geophysical Research Letters

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ER -

Semiquantitative Estimates of Rainfall Variability During the 8.2 kyr Event in California Using Speleothem Calcium Isotope Ratios

Abstract

Bibliographical note

Funding

Keywords

ASJC Scopus subject areas

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