ice field vs iceberg

ice field

noun
  • A large expanse of floating ice (several miles long). 

  • A network of interconnected glaciers or ice streams having a common source. 

iceberg

noun
  • A huge mass of ocean-floating ice which has broken off a glacier or ice shelf 

  • An aloof person. 

  • An impending disastrous event whose adverse effects are only beginning to show, in reference to one-tenth of the volume of an iceberg being visible above water. 

How often have the words ice field and iceberg occurred in a corpus of books? (source: Google Ngram Viewer )