sed‧i‧men‧ta‧tion /ˌsedəmenˈteɪʃən, ˌsedɪmenˈteɪʃən, -mən-/ noun [uncountable] technical
the natural process by which small pieces of rock, earth etc settle at the bottom of the sea etc and form a solid layer

[TahlilGaran] Dictionary of Contemporary English ▲