Abstract
Long-term perspectives on past hydroclimate variability provide context for evaluating the potential future impacts of changes in Northern Hemisphere temperatures and oceanic-atmospheric circulation on the timing and distribution of precipitation in Central America. Here we use the isotopic composition of fine-grained (< 63 μm), endogenic CaCO3 (δ18Ocalcite and δ13Ccalcite) from Lake Kail, located in the western highlands of Guatemala, to infer multi-decadal to multi-centennial-scale variability in the balance between precipitation and evaporation (P/E) over the last ∼6000 years. The sediment age model is based on 210Pb and 41 14C ages, with chronological uncertainty estimated using Bayesian methods. A model that couples lake hydrology and isotope mass balance is applied to characterize the isotopic responses of lake water and calcite to changes in drought-controlling climate variables such as precipitation, temperature and relative humidity. The δ18Ocalcite variations indicate intermediate-to-dry P/E conditions during the late-middle Holocene from ∼6000 to ∼4100 cal yr BP. There was then a shift to drier conditions at the start of the late Holocene until ∼3050 cal yr BP, followed by a trend to wetter conditions until ∼1500 cal yr BP. The most recent ∼1500 years is characterized by high and relatively stable P/E, with particularly wet intervals from ∼1500 to 1170 cal yr BP and from 470 to 260 cal yr BP. Comparisons of the Lake Kail δ18Ocalcite record with Central American/circum-Caribbean proxy datasets spanning the late-middle and late Holocene indicate northern tropical hydroclimate changes were highly variable across space and time and were likely driven by regional oceanic-atmospheric responses with a secondary influence by insolation forcing.
Original language | English (US) |
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Article number | 116327 |
Journal | Earth and Planetary Science Letters |
Volume | 542 |
DOIs | |
State | Published - Jul 15 2020 |
Bibliographical note
Funding Information:We thank Mark Abbott, Silvia Cortes, Pauline Décamps, Matthew Finkenbinder and Osmin Vasquez. This project was supported by the National Science Foundation Paleo-Perspectives on Climate Change program ( EAR-1502989 , EAR-1503069 , EAR-1502740 ). Additional funding was provided by Northern Illinois University , the Las Vegas Isotope Science Lab at the University of Nevada, Las Vegas ( NSF , EAR-0521196 ), the University of Minnesota Duluth , and The Geological Society of America , Graduate Student Research Grants program. University of Delaware Precipitation, GPCC Precipitation, and NCEP_Reanalysis 2 data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their web site at https://www.esrl.noaa.gov/psd/ .
Funding Information:
We thank Mark Abbott, Silvia Cortes, Pauline D?camps, Matthew Finkenbinder and Osmin Vasquez. This project was supported by the National Science Foundation Paleo-Perspectives on Climate Change program (EAR-1502989, EAR-1503069, EAR-1502740). Additional funding was provided by Northern Illinois University, the Las Vegas Isotope Science Lab at the University of Nevada, Las Vegas (NSF, EAR-0521196), the University of Minnesota Duluth, and The Geological Society of America, Graduate Student Research Grants program. University of Delaware Precipitation, GPCC Precipitation, and NCEP_Reanalysis 2 data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their web site at https://www.esrl.noaa.gov/psd/.
Publisher Copyright:
© 2020 Elsevier B.V.
Keywords
- Central America
- insolation
- northern tropics
- oxygen isotopes
- precipitation