Chocolate Ice?

Best on black.

As the Antarctic ice sheet heads toward the ocean it grinds across the underlying rock, in the process being worn to the profile of the rock it crosses while also gathering powdered rock dust which causes this chocolate discolouration. This berg (larger than it may appear, at about 20M high) has capsized on reaching the ocean, making the colours and diagonal wear from rocks visible.

Glaciers often pick up rocks known as "erratics" and transport them for considerable distances where, on land, they are deposited into moraines. When they are picked up by ice that becomes icebergs, they become "dropstones" and eventually fall to the bottom of the ocean - potentially thousands of kilometres from their origin. The closer shot in the insert note shows one.

Explored.