EARTHSCI Flashcards
weathering, erosion, and mass wasting have a __________ process
exogenic
what does an exogenic process mean?
near the earth’s surface
what is weathering?
slow breaking down of rocks and other materials in the earths surface over a long period of time
what are the two types of weathering?
Mechanical and chemical
this type of weathering produces smaller pieces
mechanical
what are the 5 types of mechanical weathering
abrasion, exfoliation, frost wedging, salt wedging, action of all living things.
how would you describe an abrasion?
wearing off of rocks by solid particles carried by wind, water, and other agents.
explain how wind is an agent of abrasion
wind carries sand particles that breaks them down and leads to unusual rock formations.
explain how water is an agent of abrasion
water carries rock particles, tumbling against each other causing the rocks to be round and smooth.
how are plants, animals, and humans mechanical weathering?
plants: plant roots go underground to get needed nutrients. roots get bigger and longer causing them to break
animals: burrow animals create tunnels underground for living space
humans: actions like road construction, power plants, etc.
how would you explain frost wedging?
water seeps into small cracks and expands when it freezes. The temperature must be below freezing point so the water can exert pressure
how would you explain salt wedging?
On hot days, the water evaporates leaving behind minerals. The salt crystals grow through the cracks and pushes them apart.
how would you explain exfoliation?
repeated changes of temperature causes the surface of the rocks to peel off (large, flat, or curved)
This type of weathering changes the chemical composition due to its reaction with other substances
chemical weathering
5 types of chemical weathering
Carbonation
Oxygen
Hydrolysis
Dissolution
Hydration
what is carbonation
water + carbonic acid= dissolves minerals
is rainwater acidic
yes, slightly
what are the minerals affected by carbonation
calcite (marble and limestone)
what is hydrolysis
water + other substances. breaks down chemical bonds of minerals.
what happens in hydrolysis
acid seeps to the ground and reacts chemically with other common minerals. calcite dissolves completely
what happens in dissolution
when in water, reacts with acids in the water. dissolves and creates solution. small holes are present.
what happens in oxygen
iron + oxygen = rust. oxidation occurs. chemical composition might also change.
what happens in hydration
minerals absorb water and changes composition ex: feldspar turns into clay
weathered rocks are transported from one place to another
erosion
5 agents of erosion
wind, waves, gravity, ice, and running water
wind erosion:
hot and dry; easily carried; faster wind= more particles carried
wave erosion
erode and shape shorelines. large particles are deposited to other parts of the shoreline
erosion by gravity AKA mass wasting
gravity pulls rocks and soil down the slope; ultimate transportation to the sea by running water
WHAT ARE THE TYPES OF MASS WASTING
creep
slide
flow
fall
slumps
slow, active on the surface; gradual downhill movement
creep
free falls upon failure of undercutting, motion is rapid
falls; rockfalls
downward slide of mass rock or unconsolidated materials along a curved surface
slumps
weakening of supporting rocks
landslide
occurs after heavy rain; picks up rocks and boulders causing it to be thicker
mudflow
soil, containing large amount of water
debrisflow, avalanche
factors of MW
climate
moisture
steep slopes
weak rocks
existing failure surfaces
depositing sediments by water, wind, or ice
deposition or sedimentation
builds new land on earths surface
deposition or sedimentation
river flows into an ocean or lake to build landform. triangular shape
delta
fan-shaped deposit; streams down and enters flat plain
alluvial fan
moun/ridge formed by the wind in deserts, beaches, or other sandy areas
sand dune
elongated ridges of sand
spit
partly exposed ridges/ build by waves off shore
sandbar
