An unusual type of flow feature occurs in the Cerberus plains south of Elysium and in Amazonis. These flows have a broken platey texture, consisting of dark, kilometer-scale slabs embedded in a light-toned matrix. They have been attributed to rafted slabs of solidified lava floating on a still-molten subsurface. Others have claimed the broken slabs represent pack ice that froze over a sea that pooled in the area after massive releases of groundwater from the Cerberus Fossae area.