The three main types of erosion caused by glaciers are plucking, abrasion, and freeze thawing. Plucking forces rocks off of the back wall when glacier water melts and re-freezes around cracked and broken rocks. Abrasion occurs when rocks frozen to the base of the glacier scrape the bed rock. Freeze thawing occurs when melted water gets into the bed rock. An outwash plain is an area formed by sediments at the terminus of a glacier. Outwash plains may contain suficial braided stream complexes, and kettle lakes. The outwash plains originate from melting ice deposits.