sapropel

From German Sapropel, corresponding to sapro- + Ancient Greek πηλός (pēlós, “mud, clay”).

• (UK) IPA^(key): /ˈsapɹə(ʊ)pɛl/

sapropel (plural sapropels)

1. (geology) An aquatic sludge-like sediment rich in organic matter formed in oxygen-free areas at the bottom of lakes, seas etc.
   • 2011, Chris Stringer, The Origin of Our Species, Penguin 2012, p. 47:

     Another instance in which Mediterranean sapropels have provided clues about events deep within the African continent is the ‘greening’ of the Sahara about 120,000 years ago.

• sapropelic

• prolapse, propales