sentences:  During glacial times, the lake was considerably larger, reaching a surface area of with water levels rising to about above present-day level; the lake was filled with freshwater at that time.A volcanic marker dated to 16,700 ± 2,000 years before present pre-dates the lake highstand; this volcanic marker is a tephra erupted by the Cerro Corona lava dome south of Lascar.Lake levels stayed high until the Holocene and then decreased; the timing of Holocene changes is unknown.