Hydrosphere - Landforms Flashcards
1
Q
waterfall
A
- hydraulic action = compression of air in river bank causing materials to be dislodged
- abrasion = force of water throwing bedload against rocks
- differential erosion where bands of more resistance, harder rock overlay less resistance, softer rock
- softer rock is eroded easier
- undercutting causing overhang of hard rock
- unsupported hard rock collapses to plunge pool over time
- waterfall retreats upwards
2
Q
oxbow lake
A
- meanders = large bends in middle course, w/ river cliffs on the outside bend & slip off slopes formed via erosion & deposition
- bend becomes more pronounced & neck narrows, bc lateral erosion
- lateral erosion = hydraulic action (define), abrasion (define)
- first flood bc rapid rainfall/snowmelt = water bursts banks of river = more direct route, cutting straight thru neck
- more floods = direct route more established bc more efficient = loop sealed of bc depostition at neck = oxbow lake
- oxbow lake can dry up unless theres high rainfall
3
Q
meander
A
- meander = large bend in middle course
- smaller river load bc abrasion (define) & attrition (define)
- water flows faster on outside bend = load will erode outside bend via abrasion = river bank undercut & collapses leaving river cliff
- river moves slowly on inside bend = larger pebbles deposited = slip-off slope
- helicoidal flow = corkscrew movement of deposition and erosion
- differential erosion = bands of hard & soft rock on river bed = pools and riffles = deeper and shallower areas
4
Q
v-shaped valley
A
- sources in mountains = quick downhill flow = fast vertical erosion
- vertical erosion = hydraulic action (define), abrasion (define)
- as river erodes down, valley sides exposed to freeze-thaw weathering = loosens rocks = steepends valley sides
- rocks that fell into river mean more abrasion
- rocks transported down stream via river = wider & deeper channel