A nunatak is a mountain peak or rocky ridge that protrudes above a glacier or ice sheet. Nunataks are significant as they provide evidence of past glaciation, serve as refuges for plant and animal species during glacial periods, and are important markers in studying glacial dynamics.
Reference: Sugden, D. E., & John, B. S. (1976). “Glaciers and Landscape: A Geomorphological Approach.” Edward Arnold.