Bouma sequence
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The Bouma Sequence (after Arnold H. Bouma, 1962) describes a classic set of sedimentary beds (turbidites) deposited by a sediment-water turbidity current. The Bouma Sequence specifically describes the medium grained variety, which are usually found in the continental slope or rise setting.
The Bouma Sequence is divided into 5 distinct beds labelled a through to e, with a being at the bottom and e being at the top and each bed is described by Bouma as having a specific lithology (see below). In a real Bouma Sequence, some beds may be missing - Bouma describes the ideal sequence.
The beds are:
- e: Muds, ungraded, often bioturbated.
- d: Parallel laminated silts.
- c: Cross laminated sands.
- b: Parallel laminated sands.
- a: Sands and any larger grains the turbidity current was carrying at the time of deposition.
[edit] References
- Bouma, Arnold H., 1962, Sedimentology of some Flysch deposits;: A graphic approach to facies interpretation, Elsevier, 168 pp.
- Schlumberger Oilfield Glossary
- GeologyRocks Glossary Entry
