Arctic explorer who’s lost in ice formation (4)

I believe the answer is:

berg

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'ice formation' is the definition.
(I've seen this in another clue)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for berg that I've seen before include "ice in the drink" , "Viennese composer" , "African mount" , "Lump of ice" , "South African mountain - Austrian composer" .)

I've seen this clue in The Independent.

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