Fig. 1: Palaeotemperature reconstructions from Antarctica and globally.
From: 60 million years of glaciation in the Transantarctic Mountains
a Glacier-free cirques (n = 1292) in the Transantarctic Mountains coloured according to the sea level mean summer air temperature (SL MSAT) required for them to be occupied by temperate (warm-based) mountain glaciers. The inset histogram shows the frequency distribution of SL MSAT. Antarctic coastline data from the SCAR Antarctic Digital Database, accessed [2021]49 license: https://creativecommons.org/licenses/by/4.0/. b Global surface temperature data for the Cenozoic4, highlighting key climatic periods referred to in the text, and our interpretation of the glacial history of the TAM. c Cirques ordered by SL MSAT (grey area represents the ±2.5 °C MSAT uncertainty) required for them to be occupied by temperate mountain glaciers. Colours are based on the values in subplot (a). Antarctic temperature estimates for different time periods in subplot (c) are based on published data from biological proxies (Supplementary Table 1).
