Minimal Antarctic sea ice during the Pliocene

• Published in: Geology
• Main Authors: Whitehead, JM, Wotherspoon, SJ, Bohaty, SM
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Society of America 2005
• Subjects: Earth Sciences; Physical Geography and Environmental Geoscience; Glaciology; Antarctic; Antarc*; Antarctica; Sea ice
• Online Access: https://doi.org/10.1130/G21013.1; http://ecite.utas.edu.au/34526

Antarctic sea-ice concentration at Ocean Drilling Program Sites 1165 (64.380S, 67.219E) and 1166 (67.696S, 74.787E) was lower than today through much of the Pliocene. The low sea-ice concentration is evident from the proportion of the diatom Eucampia antarctica with intercalary valves (Eucampia index). This sea-ice proxy was calibrated by using modern diatom data obtained from core-top samples and winter sea-ice concentration data (September average through 1979-1987). The modern relationship is expressed as a binomial generalized linear model (modern sea-ice model). This model was applied to the Pliocene Eucampia index within a 95% tolerance interval (obtained from bootstrap estimates). The results indicate that reduced winter sea-ice concentrations persisted through much of the Pliocene and at times were 78% and 61% relatively less concentrated than today at Sites 1165 and 1166, respectively. 2005 Geological Society of America.