Melting ice cap close to Finnish social gathering (7)
I believe the answer is:
ceilidh
'social gathering' is the definition.
(I've seen this before)
'melting ice cap close to finnish' is the wordplay.
'melting' is an anagram indicator.
'cap' becomes 'lid' (eg the lid of a bottle).
'close to' suggests the final letters (the close of something is the end).
The last letter of 'finnish' is 'h'.
'ice' with letters rearranged gives 'cei'.
'cei'+'lid'+'h'='CEILIDH'
(Other definitions for ceilidh that I've seen before include "Irish party" , "Gaelic get-together" , "Scottish singing and dancing event" , "Irish or Scottish musical get-together" , "Gathering with Celtic folk music, singing and dancing" .)