glacial granite boulder花岗岩漂砾
glacial erratic boulder冰川漂砾
glacial boulder period冰川纪
glacial boulder drift冰碛
glacial boulder dispersion冰川分散
glacial boulder gravel冰成砾石
glacial boulder cycle冰川旋回
glacial boulder valley debris冰川谷岩屑
glacial boulder striae冰川擦痕