1. Transport
This will cause a mixing of faunas from different environment
- Reworking of older sediments
- Contemporaneous transport
- As suspended load.The empty shells of dead foraminifera can be transported hundreds of miles offshore. Result:shallow water forms in deep water deposit
- By currents. This may be reflected in species or size sorted assemblages.
- By turbidity currents or slides.
- Vegetation. Attached living species may be transported over vast distances, when the vegetation is uprooted
- Wind. Empty shells of dead foraminifera may be blow land inwards
2. Bioturbation
The effect of bioturbation is rather minimal. Burrowing organisms may cause the mixing of different assemblages.
3. Diagenesis
Solution of calcareous test or the calcareous cement of arenaceous species can result in the complete absence of a fossil
4. Caving and contamination
Different preservation, colour or the degree of abrasion can be clue in determining transported or reworked faunas.
for more information please see foraminifera in http://regionalgeology.info
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