Pole cover (3,3)

I believe the answer is:

ice cap

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'cover' is the definition.
(I have seen 'permanent cover' mean 'ice cap' so perhaps 'cover' could also mean 'ice cap')

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for ice cap that I've seen before include "mountain peak, perhaps?" , "Frozen polar region" , "Permanent covering of frozen water" , "Permanently frozen mountain-top mass" , "polar area" .)

I've seen this clue in the Sydney Morning Herald.

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