History of Taylor Valley
Taylor Valley has been the site of extensive glaciation and deglaciation during the past 20,000 years, which has strongly affected lake water levels in the valley over time (Hall et al. 2000, Lawrence and Hendy 1989, Myers et al. 2021). Ice from the Ross Ice Shelf advanced into the valley during the Last Glacial Maximum (LGM) (28.5-12.8 years BP) when local air temperatures were 4-9 °C lower than modern (Steig et al. 2000). Ice sheet advance resulted in an ice dam at the mouth of Taylor Valley which reached elevations up to 300-350 meters above sea level (m.a.s.l.) and allowed the formation of a large paleolake, Glacial Lake Washburn (GLW), which filled all of Taylor Valley (Hall and Denton 2000, Lawrence and Hendy 1989, Myers et al. 2021). Lake levels in Taylor Valley have undergone drastic changes since the LGM; post-LGM ice dam retreat caused drainage of GLW and lowered lake levels to approximately 81 m.a.s.l. (Levy et al. 2017, Myers et al. 2021). Lake levels fell further as drainage into the Ross Sea continued, and high rates of evaporation likely resulted in the formation of a shallow brine pond in the Fryxell basin around 1000 years BP (Lawrence and Hendy 1989, Levy et al. 2017). Lake basins subsequently refilled with glacial melt waters, and lake levels have been rising since observations began during Robert Scott’s first expedition in 1903 (Doran and Gooseff 2022, Myers et al. 2021, Scott 1905).