Earth Sci - The G's

Question 1

weathering

Answer 1

the breakdown of rock into smaller and smaller pieces

Question 2

sediments

Answer 2

fragments of weathered rock

Question 3

erosion

Answer 3

the movement of rock fragments (may also cause further weathering of fragments into even smaller pieces)

Question 4

deposition

Answer 4

the drop off of rock fragments at a new location

Question 5

6 agents of erosion/deposition

Answer 5

(unsorted) gravity, groundwater, glaciers

(sorted) waves, wind, water

Question 6

gravity

Answer 6

force behind all erosion

Question 7

erosion vs deposition (which one is dominant)

Answer 7

erosion - kinetic energy/speed of agent is high

deposition - kinetic energy/speed of agent is low

Question 8

1. weathering (definition + when it occurs)

Answer 8

definition: breakdown of rocks at Earth’s surface

occurrence: occurs due to exposure of the lithosphere to air, water, chemicals, and organisms

Question 9

2. physical weathering (definition)

Answer 9

breakdown of rocks without change in the rock’s composition

Question 10

frostaction (physical weathering) (definition + climate)

Answer 10

definition: when water expands as it freezes (approx. 10%) and causes cracks in rocks to grow larger

climate: alternating between freezing/thawing (causes most damage) (temps above/below 0o), cold & wet climate

Question 11

abrasion

Answer 11

collisions and scraping between rocks as they move

Question 12

exfoliation

Answer 12

the “peeling away” of rock layers. the removal of overlaying rock layers reduces pressure and the rock expands upwards, resulting in exfoliation (like an onion)

Question 13

plantaction

Answer 13

when plants help to breakdown rock (root wedging)

Question 14

lichens

Answer 14

can cause both physical and chemical weathering of rocks

Question 15

3. chemical weathering (definition + occurrence)

Answer 15

definition: breakdown of rock with a change in the rock’s composition

occurrence: typically involves air, water, and/or chemicals

Question 16

oxidation

Answer 16

when oxygen combines with other elements to form a new compound (e.g. rust)

Question 17

carbonation

Answer 17

carbon dioxide can combine with water to form a mild acid which can weather rocks (can form from other pollutants as well).

calcite is particularly susceptible (H2O+CO2⟶H2CO3)

Question 18

hydrolysis

Answer 18

water can react with minerals in a rock (e.g. water reacts with feldspar to produce clay minerals)

Question 19

dissolving

Answer 19

when a rock becomes incorporated into liquid water to form a solution (solvene does dissolving, solute gets dissolved)

Question 20

4. factors affecting the rate of weathering

Answer 20

particle size, particle shape, rock hardness, climate

Question 21

particle size

Answer 21

• smaller particles have more surface area than an equal volume of larger particles
• small rocks weather faster than an equal volume of large rocks

Question 22

particle shape

Answer 22

• as rocks weather, their shape becomes more rounded
• angular rocks have more surface area than an equal volume of rounded rocks, therefore angular rocks weather faster than rounded rocks

Question 23

rock hardness

Answer 23

rocks have specific chemical and physical properties that influence the rate and manner in which they weather

Question 24

which rocks are resistant to weathering?

Answer 24

rocks that tend to be resistant will be
- higher in elevation
- jut out from a cliff
- steep cliff face

Question 25

climate

Answer 25

frost action: climate should be cold/wet (alternating between freezing and thawing)

most chemical weathering: climate should be hot/wet

Question 26

5. sediments and soils