3.4 FLUID-SEDIMENT INTERACTION 1 SED MOTION & BEDFORMS Flashcards
1
Q
What forces are clays subject to?
A
Electrochemical inter-particle forces
2
Q
What are the total forces acting on a grain?
A
- lift component
- drag component
- fluid force
- gravity force
3
Q
What behaviour applies to muds/sand-mud mixtures with clay contents above a certain %?
A
Cohesive (sticky) behaviour ; >15-20%
4
Q
Stabilising biotic factors
A
- biofilms (EPS) or filamentous networks
- compaction by burrowing macrofauna increases density
- sediment armouring: orgs cover surface, shielding sediment
- biofiltration & biodeposition: filter feeding removes suspended sediment
5
Q
Destabilising biotic factors
A
- pelletisation enhances erodability
- grazing reduces stabilising influence of microphyto-benthos
- burrow cleaning results in ejected material
- blistering-bubble formation under biofilms results suspension
