streams: transport to the ocean

Chapter 10: Chapter 10: Streams: Transport to the oceanStreams: Transport to the ocean

1. Hydrological cycle

2. Stream profile and erosion

3. Sediment transport and deposition

4. Meanders

5. Deltas

1) The hydrological cycleStreamsStreams

hydrological cycle:Continuous cycling of water between the atmosphere, oceans and land, due to gravity and energy from the Sun

Some factors: amount of rainfall rate of evaporation runoff

The hydrological cycleThe hydrological cycle

oceansoceans damsdams

rivers

rivers

soilsoil

lakeslakes

plantsplants

snowsnow

mountainsmountains

rainrain

evaporationevaporation

10 elements that are10 elements that areinterrelated in the hydrological cycleinterrelated in the hydrological cycle

2) Stream profile and erosion2) Stream profile and erosionStreamsStreams

longitudinal profile:Steep gradient at head and almost flat at mouth.

Base level:The downward limit to which a stream can cut/erode host rock (“bottom of the hill”).

See Figs 14.13,14,15

2) Stream profile and erosion2) Stream profile and erosionStreamsStreams

Over time streams can erode rock just like sandpaper

3) Sediment transport & deposition3) Sediment transport & depositionStreamsStreams

Stream transport mechanisms:Stream transport mechanisms: in solution (dissolved in water) in suspension bed load (along bottom)

See Fig. 14.2

3) Sediment transport & deposition3) Sediment transport & depositionStreamsStreams

Stream transport mechanisms:Stream transport mechanisms:

in solution (dissolved in water) in suspension bed load (along bottom)

3) Sediment transport & deposition3) Sediment transport & depositionStreamsStreams

Sediment deposition:Sediment deposition: channel deposits floodplain deposits alluvial fans & deltas Alluvial Fan (Death Valley, CA)

Fig. 14.17

4) Meanders4) Meanders

Floodplain:

Stream channel deposits left by meandering rivers.

Fig. 14.9

Oxbow lake

4) Meanders4) Meanders

5) Deltas5) DeltasStreamsStreams

Delta:Delta: depositional platform that forms at the mouth of a river

Distributaries:Distributaries: smaller streams that branch off downstream

Fig. 14.23

Salt marshes:Salt marshes: shallow bays between distributary channels

Multiple choiceMultiple choiceStreamsStreams

 Which of the following terms describes a curved, coarse-grained deposit that forms on the inside curve of a stream?

A. duneB. meanderC. oxbowD. point bar

Multiple choiceMultiple choiceStreamsStreams

Curves and bends in a stream channel are called ______.

A. alluvial fansB. braidsC. deltasD. meanders

Multiple choiceMultiple choiceStreamsStreams

 At a bend in a river, ______ occurs on the outside of the bend and ______ occurs on the inside of the bend.

A. deposition. . . depositionB. deposition . . . erosionC. erosion . . . deposition D. erosion . . . erosion

Multiple choiceMultiple choiceStreamsStreams

  Which of the following would be the most fertile area for crops?

A. a stream channelB. a floodplainC. a natural leveeD. an uplands area away from the stream

Multiple choiceMultiple choiceStreamsStreams

 Large, cone-shaped deposits of sediment at a mountain front are called ______.

A. alluvial fansB. deltasC. natural leveesD. terraces