layers of snow that react to different conditions.
Blue stripes are often created when a crevice in the ice sheet
fills up with meltwater and freezes so quickly that no bubbles form.
When an iceberg falls into the sea, a layer of salty seawater can
freeze to the underside. If this is rich in algae, it can form a
green stripe.
Brown, black and yellow lines are caused by sediment, picked up
when the ice sheet grinds downhill towards the sea.
