Terrain in the study area, showing lakes Maruwan, Maruwan-minami, and Maruwan-kita and associated geomorphic features. The locations of the images are shown by labels a to g in Figure 1a (lower left panel). (a) Overall features of the study area, showing the proximity of the lakes to Rundvåg Glacier, and the overflow points of lakes Maruwan and Maruwan-minami. (b) Lateral moraine close to Rundvåg Glacier. (c) Outflow of L. Maruwan. (d) Possible subglacial erosion features (after Sawagaki and Hirakawa 1997). (e) Present-day microbial mat (dark area) and erratic boulders transported and deposited by past glaciers. (f) Exposed stratification in glacial ice. (g) Detail of (a), showing a cave-like structure beneath the glacier.