September GSA Today cover photo: National Elevation Dataset shaded relief image of Minnesota, USA, by Paul Morin of the University of Minnesota’s Polar Geospatial Center, showing the Lake Agassiz basin (NW), an ice stream path (SW), gullies along the Mississippi (SE), and Archean terrane (NE).
The linear streaks shown on this aerial photograph are believed to have been gouged by icebergs dragging on the bottom of wind swept Glacial Lake Agassiz. The streaks (Lat. 48 50′ 45″ N; Lon. 97 15′ 30 W) are up to several miles long, hundreds of feet wide and several feet deep. Credit: NRCS Web Soil Survey. (via AGU Blogosphere | terra central | Iceberg Drag Marks on the Bottom of Glacial Lake Agassiz)