Bouma sequence

The Bouma sequence (named after Arnold H. Bouma [nl], 1932–2011[1]) describes a classic set of sedimentary structures in turbidite beds deposited by turbidity currents at the bottoms of lakes, oceans and rivers.

The Bouma sequence specifically describes the ideal vertical succession of structures deposited by low-density (i.e., low sand concentration, fine-grained) turbidity currents.

[3] When energy within a flow is highest, it can carry the maximum amount of sediment and the largest grain sizes, but as energy decreases, the carrying capacity reduces, and the coarsest grains quickly settle out, sometimes almost instantaneously.

Ultimately, only clay particles remain, suspended in a stagnant water column with essentially no current movement.

[3] As flows move downslope the following processes take place to create the layers of the Bouma sequence.