Climate history of the southwestern United States based on Estancia Basin hydrologic variability from 69 to 10 ka.

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]