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
