Icebergs sometimes have stripes, formed by layers of ice deposited on different conditions. Blue stripes are created when a crevice in the ice sheet fills up with melted water and freezes so quickly that no bubbles form. Green stripes form when an iceberg falls into the sea and a layer of water rich in algae freezes onto the bottom. Brown, black and yellow lines are caused by sediment, picked up when the ice sheet grinds downhill towards the sea.
(Photos: Antarctica Series by Steve Nicol)