A Progressively Wetter Early through Middle Holocene Climate in the Eastern Lowlands of Guatemala
Climate records from Central America and the Caribbean region reveal considerable spatiotemporal complexity in precipitation variability, with multiple hypotheses explaining the likely ocean-atmosphere processes influencing precipitation in the region. Here we report on findings from a 760-cm long sediment core from Lake Izabal, eastern Guatemala that affords insight on regional hydroclimate change over the last ∼9,500 years. We utilized a radiocarbon-based age-depth model integrated with lithological, XRF elemental abundances, and principal component analyses to infer changes in erosion/precipitation, lake productivity, and lake water chemistry. Abundance of elements commonly associated with terrigenous sources increase from the early to the latest mid-Holocene, from ca. 9,500 to ca. 4,800 calibrated years before present (cal yr BP), suggesting a progressive increase in erosion/precipitation. This is followed by relatively stable and high erosion/precipitation conditions until ca. 1,200 cal yr BP, with an abrupt decrease in erosion/precipitation ∼1,200 years ago. Comparison of the Izabal record with other paleoclimate records from Central America and the Caribbean region indicates substantial heterogeneity in hydroclimate, even across relatively short distances, likely due to a combination of topographic complexity and the combined influences of Atlantic and Pacific basin ocean-atmosphere dynamics. Our results suggest that the progressive increase in boreal autumn insolation throughout the middle and late Holocene may have driven an increase in Caribbean sea-surface temperatures (SST) during the late wet season, leading to increased moisture availability through enhanced evaporation and greater precipitation amounts associated with zonal convergence and orographic uplift along the eastern coast of Central America. However, other nearby records demonstrate hydroclimate changes that are at least partially at odds with the Izabal record, indicating that the modern SST relationships with atmospheric circulation, including Intertropical Convergence Zone dynamics, and precipitation alone cannot be used as a framework for explaining hydroclimate variability across Central America during the Holocene.
E. Duarte et al., "A Progressively Wetter Early through Middle Holocene Climate in the Eastern Lowlands of Guatemala," Earth and Planetary Science Letters, vol. 561, Elsevier, May 2021.
The definitive version is available at https://doi.org/10.1016/j.epsl.2021.116807
Geosciences and Geological and Petroleum Engineering
Keywords and Phrases
Lake Izabal; Elemental abundances; Precipitation; Autumn insolation; Sea surface temperatures
International Standard Serial Number (ISSN)
Article - Journal
© 2021 Elsevier, All rights reserved.
01 May 2021
This research was supported by two Geological Society of America Graduate Student Research Grants, an American Association of Petroleum Geologists Grants-in-Aid, and the Visiting Graduate Student Program from the National Lacustrine Core Facility and the Continental Scientific Drilling Coordination Office.