Glacier, king Haakon Bay

A Zodiac cruise along the snout of the glacier at the head of King Haakon Bay gave me a chance to sketch the basic forms; it took a bit of experimentation to try to capture the intense blue-greens that appear to emanate from a light source within the glacier itself. a first try, I'm keen to return to this subject and play around a bit more with the colours. This was a fairly clean glacier, but others have various bands of earth colours running through them. I'm not sure of the origin of these bands, any glaciologist reading this is welcome to provide an explanation.
On arches 300gsm rough paper again, 22x15"