Review Test Flashcards
In what climates does the fastest chemical weathering occur?
Warm & moist climates ☀️☔️
Types of Weathering?
Chemical & Physical
Where does chemical weathering typically occur in rocks?
On the surface of rocks rather than inside them
Oxidation
Iron+oxygen=rust
Hydrolysis
Minerals in rocks react with ions in water forming clays
Dissolution
Rocks (especially limestone) react with acids in water
Frost action?
Water gets into cracks- freezes- expands- enlarges the crack
Wave action
Waves pound against rocks- sand and rocks in the waves help to break up the shoreline
Stream abrasion
Rocks are rounded and smoothed from tumbling down the river. Such rocks downcut the streams V-shaped channel
Wind abrasion
Wind causes sand to blow against rocks causing pitting
What factors play into physical weathering?
Resistance (hardness) of the rock and the type of climate
What does weathering have to do with soil?
Without weathering, there would be no soil, none of the minerals in soil would be there
What causes erosion to occur?
Gravity- the driving force of erosion
Agent of erosion?
Running water is the #1 agent of erosion
How does running water transport particles?
- In suspension
- By floatation
- Rolling along the bottom (saltation)
- In solution
The faster the streams velocity…
…the higher the rate of stream erosion
Stream velocity depends on…
…slope, stream volume (more water=faster river), shape of channel (if it narrows velocity increases
Straight stream=?
Fastest and deepest in the center
Curved stream=?
Fastest and deepest on outside of curve
If a channel becomes narrow, does that increase or decrease the rivers velocity?
Increases it, if a channel widens or enters a lake or ocean, then the velocity will decrease
How do the sediments being carried by the river relate to its velocity?
Sediments carried in suspension always move more slowly than the water of the stream
In a straight stream water moves fastest…
…at the surface in the center
How does stream abrasion affect the rocks being carried?
They become rounder, smoother and smaller
How do streams sort sediment?
Biggest, densest and roundest settle fastest, and therefore are on the bottom of the stream