Golunvolo, thank you, the formation is natural. Wind, snow and water sculpt extraordinary shapes, and I also though this one was reminiscent of an Easter Island head.
Anirban, thank you, the colours vary according to the light, but also as a result of events at the time of formation of the ice - the saltiness of the water is important, and also the salt can sometimes leave the ice. They are much more complicated than I ever thought.
As for metering, Nikon matrix metering was surprisingly accurate, although sometimes I opened up the aperture a little. There was a lot of trial and error!
