CENTENNIAL-SCALE SOLAR(?) FORCING OF LAST GLACIAL MAXIMUM CLIMATE IN THE ESTANCIA BASIN OF NEW MEXICO

X-ray fluorescence (XRF) and X-ray diffraction analyses of sediments from the Estancia Basin of central New Mexico reveal previously unknown centennial-scale oscillations in the volume of closed basin Lake Estancia during last glacial maximum (LGM) time. LGM sediments consist of a mixture of authigenic carbonates, detrital quartz, and gypsum. Quartz originated in the Manzano Mountains on the western edge of the basin and was delivered to the lake in stream flow pulses that spread across the surface of the saline lake during freshening events. Gypsum precipitated in mud flats exposed during lake lowstands and was blown into the lake. XRF measurements of calcium abundance show ~17 regular oscillations between 20,080 and 15,130 ¹⁴C years b.p. Multi-taper method spectral analysis of these variations yields dominant periods of 355, 312, and 275 calendar years, similar to cycles in ¹⁴C production reported by Damon and Peristykh (2000) and Damon and Jirikowic (1992). As such, Lake Estancia sediments may record variations in solar activity during LGM time. Confirmation of these results awaits additional age control.