4.1.2c Fluvial Environment A-Level Geology OCR

What is the term used to describe a rivers point of origin

• source

• tributary

• mouth

• point bar

Tick all the sedimentary structures you might expect to find in a fluvial environment (channel, point bars and flood plains)

• Desiccation cracks

• X-bedding

• Imbricate structure

• Flute casts

Deposition in a fluvial environment is caused by...

• Moving water losing energy

• Particles in the water being too small

• An increase in river velocity

• Particles rubbing against the bed and banks

Which transport process involves large boulders and rocks being rolled along the river bed?

• Saltation

• Traction

• Suspension

• Solution

In which part of the river will erosion dominate with very little deposition?

• Upper course (i.e by the source)

• Middle course (central meandering system)

• Lower course (delta / estuary)

• On the floodplain

Name the type of river system shown in the diagram

• Meandering

• Braided

• Straight

• Anastomising

What is the general term for unconsolidated clay, silt, sand, gravel, and mineral fragments deposited by running water

• Alluvium

• Deposition

• Aggradation

• Degradation

Identify the sedimentary structure common in fluvial environments

• Flute casts

• Desiccation cracks

• Imbricate structure

• Cross bedding

Which of the following are true with distance from the source (tick all that apply)

• Grains become coarser

• Grains become more rounded

• Grains become finer

• Grains become more angular

Name a rock type deposited on a flood plain