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 |
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Article number | e2020GL089154 |
Journal | Geophysical Research Letters |
Volume | 48 |
Issue number | 3 |
DOIs | |
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‐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 |
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National Science Foundation Arctic Social Science Program | AGS‐1554998 |
National Science Foundation Arctic Social Science Program | |
U.S. Department of Energy EPSCoR | |
Geological Society of America | |
Lawrence Livermore National Laboratory | DE‐AC52‐07NA27344, LLNL‐JRNL‐807062 |
Lawrence Livermore National Laboratory | |
National Geographic Society | NGS‐39815 |
National Geographic Society | |
Seventh Framework Programme | 307582 |
Seventh Framework Programme | |
Karst Waters Institute |
Keywords
- calcium isotopes
- climate whiplash
- speleothem
- strontium isotopes
ASJC Scopus subject areas
- Geophysics
- General Earth and Planetary Sciences