ice sheet 
noun
A layer of ice covering an extensive tract of land for a long period of time.Several scientists have proposed that the southern part of the Greenland ice sheet disappeared during the period of maximum interglacial warmth....
- Younger cited evidence for extensive ground freezing in SE England during the Devensian, beyond the limit of the Devensian ice sheet.
- Later, as the permafrost melted and the ice sheet warmed as a result of climatic amelioration, the ice would have become wetbased.
- in (or into) the groove
- in orle
- in (or like) a flash
- in (or of) a twitter
- in (or on) form
- in (or out of) character
- in (or out of) circulation
- in (or out of) condition
- in (or out of) contention
- in (or out of) fashion
- in (or out of) favour
- in (or out of) keeping with
- in (or out of) key
- in (or out of) line with
- in (or out of) phase
- in (or out of) someone's hair
- in (or out of) step
- in (or out of) stock
- in (or out of) sync
- in (or out of) the betting
- in (or out of) the loop
- in (or out of) the running
- in (or out of) training
- in (or out of) tune
- in (or over) the course of time