ESS Unit 3 Part 2 - Erosion

movement of weathered material

erosion

shapes and lowers Earth’s surface (moves sediment)

effect of erosion

energy for erosion comes from? (driving force)

gravity

gravity in erosion: ______ differences cause movement from ____ to ____

elevation, high, low

the Sun in erosion drives the ______ _______

water cycle

the Sun in erosion “fuels” ____ and creates ______ ______

winds, ocean currents

major agents of erosion

mass wasting (gravity), streams/rivers, wind, glaciers

when rocks, soils, sediment, and snow move (slide/flow/fall) down a slope

mass wasting

factors that control mass wasting

slope angle, material (harder), vibrations, vegetation, addition of weight, ground water

slope angle MW factor:

mass wasting INC, direct

material MW factor:

mass wasting DEC, indirect

vibrations MW factor:

mass wasting INC, direct

vegetation MW factor:

mass wasting DEC, indirect

addition of weight MW factor:

mass wasting INC, direct

ground water MW factor:

mass wasting INC, direct

Organize slowest to fastest:

Rock/land slide; Mudflow; Slump; Rock fall; Hillside Creep Glacier Movement; Debris/snow avalanche

Hillside creep glacier movement, slump, mudflow, rock/land slide, debris/snow avalanche, rock fall

types of MW

rockfall, creep, slumping, landslide/mudflow

creates “talus” slope

rockfall MW

slow down slope movement of soil

creep MW

slumping MW: ____ _____ of ____ material/rock layer “_____ ____” and moves _______

large mass, loose, breaks off, downhill

landslide/mudflow MW: triggered by ______, ______ ______, or ______ ______ and has potential to be ______

vibrations, tectonic activity, heavy rain, massive

basic characteristics of streams:

(1) All streams flow ____ __ _____, (2) water held within a _____/_____ ____, (3) well sorted/_____, (4) young streams produce ______ _______, (5) ______/drainage basins, (6) stream _____

head to mouth, channel/stream bed, fluvial, V-shaped valleys, watersheds, load

areas of land that stores/drains any one or multiple streams

watersheds/drainage basins

stream load; streams carry weathered material in four different ways:

solution, suspension, saltation, bedload (traction/rolling)

SL: smallest sizes, dissolved materials, incl. salts

solution

SL: small particles carried in the flow of water

suspension

SL: larger sizes (sand and greater) can be “bounced” along the streambed

saltation

SL: largest sediment (boulders) are rolled/slid along during heavy stream flow events

bedload

results form the top layers of rock eroding slower than bottom layers because they are more resistant to weathering

waterfalls

waterfall formation caused by ______ erosion/weathering or _______

differential, undermining

types of waterfalls

cascade, cap rock

stream flow factors

velocity, maturity, gradient, discharge, competence, capacity

SFF: distance water travels in a given amount of time (speed)

velocity

______ slows down the water close to the river banks, surface, and river bed

friction

stream velocity (when straight) fastest in the ______ just _____ ___ ______

middle, below the surface

velocity is fastest along ______ edge (____) at a ____/_____

outside, bank, bend/meander

S-shaped loops in streams/rivers called:

meanders

parts of a stream:

cut bank (outside), point bar (inside)

an ______ _____ forms when it takes too much energy to keep meandering

oxbow lake

SFF: streams naturally progress from youthful → mature → old

maturity

more meanders = ____ stream

older

SFF: steepness/slope of the streams

gradient

the steeper the slope, the ____ the stream

faster

SFF: total volume of water that passes a certain point in a given time (larger volume = faster velo)

discharge

SFF: a measure that describes the max size particles a stream can carry

competence

SFF: total amt of sediment a stream can carry (total vol)

capacity

usually found in dry, arid climates

loose small sediments carried along surface causing abrasion

moderately sorted aeolian

wind erosion

wind comes from the _____ side towards the _____ side to form ____ _____

windward, leeward, sand dunes

factors of glaciers:

(1) rivers of ___ that flow (___) _______. (2) sediments are _____ (____). (3) form ________ _____. (4) can move very large sediments; soil left behind is _____ NOT _______

ice, fluid, downhill, unsorted, till, U-shaped valleys, transported, residual

glacial features

polished rock, plucked erratics, drumlins, striations, U-shaped valleys

well sorted usually:

fluvial (water)

moderately sorted usually:

aeolian (wind)

not sorted usually:

till (glaciers)