| Term: | Polythermal glacier |
| Definition: | A glacier containing some cold ice and some temperate ice. Classically, as first described, a polythermal glacier has a basal layer of temperate ice overlain by a layer of cold ice (panel a in Figure 9), above which there may be a surface layer up to about 1015 m thick that warms to the melting point seasonally. See cold glacier, temperate glacier. |