kettle hole

noun1

1. •
   A depression in the ground occurring as the result of a large block of ice getting buried by glacial outwash and subsequent melting of it.

   • An adult male mammoth and four juveniles, trapped about 14,500 years ago in a boggy ʽkettle holeʼ left by a retreating glacier in Shropshire, are the most recent record in the UK. — 2018