The most common and most likely answer to this crossword clue is the 10 letter word GLACIATION
I've seen this crossword clue in Financial Times
G
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The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GLACIATION mean?
GLACIATION noun- The process of covering with a glacier, or the state of being glaciated; the production of glacial phenomena; an ice age
- A particular instance of glacier formation.
- The act of freezing.