15 Terrestrial records of hydroclimate variability from the Pleistocene through the Common Era

Landscapes respond to climatic variability, extreme hydrologic events, and long-term environmental change, informing water resource management. We invite terrestrial proxies of hydroclimate from perspectives in paleoclimatology, geomorphology, or hydrology. Submissions from early-career scientists are encouraged.

Monday, 9 March 2026
1:30 PM - 3:30 PM
RCC, 105

Preliminary results: An annually resolved lake sediment δ18O record from lowland Guatemala

Paper number: 15-2
Program: Technical Sessions
Time: 1:50 PM – 2:05 PM

Authors

Abstract

High-resolution climate reconstructions are scarce in Central America, limiting our ability to understand how precipitation patterns respond to changing climatic boundary conditions over long timescales. Establishing a robust isotope-precipitation calibration is necessary to improve paleoclimate interpretations and future hydroclimate projections in this region, which is highly vulnerable to hydroclimatic extremes. Of the paleoclimate records that exist in Central America, many are contradictory, highlighting the need for quantitative and local-scale records. To address this knowledge gap, we present an annually resolved record of bulk authigenic carbonate δ18O, developed from a varved sediment core recovered from Lake Lachuá in the tropical lowlands of Guatemala. Lake Lachuá is a steep-sided karstic lake that preserves continuous, annually laminated sediment, allowing oxygen isotope records to be directly linked to instrumental meteorological data. The Lake Lachuá water column and sedimentary δ18O archive are highly sensitive to changes in effective moisture (i.e., the ratio of precipitation to evaporation; P/E), reflecting variability in the degree of evaporative enrichment through time. Comparisons between our Lake Lachuá δ18O record and instrumental P/E data spanning the past ~100 years were used to quantify the relationships between P/E and sedimentary δ18O. These relationships will form the backbone of future paleo-hydrological calibrations, allowing δ18O values in older sediments extending beyond the instrumental record to be used to quantitatively reconstruct hydroclimate variability in the western Central American lowlands.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411684

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