This shuttle image shows a winter view of the Mistastin Crater, a heavily eroded complex structure. Eastward-moving glaciers have drastically reduced the surface expression of this structure, removing most of the impact melt sheet and breccias and exposing the crater floor. Glacial erosion has also imparted an eastward elongation to the crater that is particularly evident in the shape of the lake that occupies the central 10 kilometers of the structure. Horseshoe Island, in the center of the lake, is part of the central uplift and contains shocked Precambrian crystalline target rocks. Just beyond the margins of the lake are vestiges of the impact melt sheet that contains evidence of meteoritic contamination. Other evidence of impact includes shatter cones, planar deformation features in quartz and feldspar, and diaplectic glasses.
Space shuttle image STS61A-34-093.