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Eolian landforms in Estancia basin, central New Mexico, record two episodes of extreme drought and low groundwater levels during the middle Holocene (7000-5400 [sup 14]C yr B.P.), followed by a rise in the water table through the late Holocene. Blowouts and associated lunettes formed when water levels fell below the desiccated floor of pluvial Lake Estancia, allowing widespread deflation. Elevation of the water table in the basin is regulated by a balance between evaporation from playas that occupy the blowouts and recharge of aquifers in the adjacent Manzano Mountains. Isotopic analyses of modern precipitation and groundwater reveal that recharge originates primarily as winter moisture, which is amplified during El Niños and diminished during La Ni˜as. Thus, changes in the elevation of a reconstructed Holocene water table may reflect systematic changes in El Niño-Southern Oscillation (ENSO) circulation. [ABSTRACT FROM AUTHOR]

Examines the paleoclimatic information from Estancia basin, New Mexico. Indications of submillennial Pleistocene climatic oscillations provided by lake sediments in the basin; Reconstruction of changes in salinity and inferred episodes of wet and dry climate; Correlation of ostracode zones and carbon dating; Changes in hydrology and climate.

Abstract Newly acquired U Th dates on gypsum sands contained within Pleistocene lake sediments allow us to extend the record of climatic change in the Estancia Basin of central New Mexico back to ∼69 ka from a previous limit of ∼29 ka. Using a hydrologic balance index (HBI) that reflects variations in sediment mineralogy and bedding characteristics, we find strong similarities to speleothem oxygen isotopic records for the southwestern United States as well as to isotopic variations in Greenland ice cores. Intervals of wetter climate in the Estancia Basin generally appear to correlate to colder conditions in the North Atlantic and conversely. The existence of a pronounced dry period from 18.1 to 17 ka matches in timing the Extrapolar Climate Reversal of Asmerom et al. (2017) at Fort Stanton cave in southern New Mexico and confirms a different origin for this stadial-like event. Furthermore, the new U Th dates support the existing Estancia Basin interpretation of a dry Bølling/Allerød followed by a wet Younger Dryas, a result consistent with speleothem and wet meadow evidence from New Mexico and Arizona (Asmerom et al., 2010, 2017; Polyak et al., 2004; Hall et al., 2012; Wagner et al., 2010) but in conflict with an interpretation of speleothem evidence from central Texas (Feng et al., 2014). Highlights • U Th dates extend the record of climatic change in the Estancia Basin of New Mexico to ∼69 ka. • The dates were acquired from gypsum sands produced during lowstands of pluvial Lake Estancia. • A new U Th date provides support for a wet Younger Dryas interval in central New Mexico. • A dry period from 18.1 to 17 ka matches in timing the Extrapolar Climate Reversal at Stanton Cave. • An Estancia Basin hydrologic balance index shows similarities to the Greenland ice sheet record. [ABSTRACT FROM AUTHOR]