Lake Sediment Stable Isotope Record of Middle to late Holocene Hydroclimate Variability in the Western Guatemala Highlands
Earth and Planetary Science Letters
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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 (Ocalcite and Ccalcite) 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 Ocalcite 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 Ocalcite 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.
Central america; Oxygen isotopes; Northern tropics; Insolation; Precipitation
Earth Sciences | Geology | Physical Sciences and Mathematics
Stansell, N. D.,
Steinman, B. A.,
Lachniet, M. S.,
Shea, C. J.,
Lake Sediment Stable Isotope Record of Middle to late Holocene Hydroclimate Variability in the Western Guatemala Highlands.
Earth and Planetary Science Letters, 542