- Bouma sequence
The Bouma Sequence (after Arnold H. Bouma, 1962) describes a classic set of sedimentary beds (
turbidites ) deposited by a sediment-waterturbidity current . The Bouma Sequence specifically describes the medium grained variety, which are usually found in thecontinental 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.References
* Bouma, Arnold H., 1962, "Sedimentology of some Flysch deposits;: A graphic approach to facies interpretation", Elsevier, 168 pp.
* [http://www.glossary.oilfield.slb.com/Display.cfm?Term=Bouma%20sequence Schlumberger Oilfield Glossary]
* [http://www.geologyrocks.co.uk/glossary/bouma_sequence GeologyRocks Glossary Entry]
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