Earth Science Exo/Endogenic

Question 1

is a process when rocks are breaking into smaller pieces whether physically or chemically.

Answer 1

Weathering

Question 2

happens when rocks break up into tiny pieces without a change in their composition.

Answer 2

Physical or Mechanical weathering

Question 3

joints originally form when decompression causes rocks to crack. This typically occurs as the forces of erosion remove the rock’s overburden (i.e. the stuff on top of it.) “Exploding rocks” in deep mineshafts are also fracturing as a result of uneven unloading.

Answer 3

Unloading

Question 4

when water gets inside the joints, alternate freezing and thawing episodes pry the rock apart.

Answer 4

Frost wedging

Question 5

process wherein tectonic forces lift deeply buried rocks close to the surface and then erosion removes overlying rock, removing the pressure, and causing the rock to expand and fracture

Answer 5

Pressure release

Question 6

a process that consists of the grinding and rounding of rock surfaces by friction and impact caused by waves and glaciers. (Takes longer compared to other physical weathering, when air,water passes(agi) through the rock and reacts to it)

Answer 6

Abrasion

Question 7

force exerted by salt crystal that formed as water evaporates from pore spaces or cracks in rocks can cause the rock to fall apart.

Answer 7

Salt crystal growth

Question 8

a process in which a crack in a rock is expanded by plant roots or broken by and animals (including humans).

Answer 8

Biological or Organic activity

Question 9

occur when temperature changes rapidly, causing the surface of the rock to heat or cool.

Answer 9

Thermal expansion and contraction

Question 10

happens when rocks break down into tiny pieces and changes rock’s composition or internal structure of minerals. Some of its causes are oxidation, leaching, hydration, and carbonation. The following are examples of chemical weathering.

Answer 10

Chemical weathering

Question 11

a process in which a mineral or rock dissolves in water forming a solution like halite (rock salt) dissolved in water. Dissociation of molecules into ions

Answer 11

Dissolution

Question 12

a process in which a mineral reacts with water to form a new mineral that has water as part of its crystal structure like feldspar to clay.

Answer 12

Hydrolysis

Question 13

a process in which a mineral decomposes when it reacts with oxygen like the rusting of iron.

Answer 13

Oxidation

Question 14

4 Main Exogenic Processes

Answer 14

(Mnemonics: W,E,D,M) Weathering, Erosion, Deposition, Mass Wasting

Question 15

5 Factors that affect the type, extent, and rate at which weathering takes place:

Answer 15

(Mnemonics: C, RT, RS, T, T) Climate, Rock Type, Rock Structure, Topography, Time)

Question 16

is the removal of rocks and soil. If a channel is composed of bedrock, erosion is accomplished by the abrasive action of water armed with sediment. If a channel is composed of loose material, considerable lifting and removal can be accomplished by the impact of water alone.

Answer 16

Erosion

Question 17

is when a stream slows down, its velocity decreases and its competence reduced and sediments begin to drop out, largest particles first and then begin to settle out. Particles of the same size are deposited together.

Answer 17

Deposition

Question 18

is the movement of rock, soil, and regolith downward due to the action of gravity. It occurs on both terrestrial and submarine slopes. It is called slope movement. It does not require transporting medium like erosion. (Examples: Mudflow, Avalanche, Landslide)

Answer 18

Mass wasting or slope movement

Question 19

7 Types of Physical/Mechanical Weathering

Answer 19

(Mnemonics: P,U,T,A,OA,FW,SCG) Pressure release, Unloading, Temperature, Abrasion, Organic Activity, Frost Wedging, Salt Crystal Growth

Question 20

3 Types of Chemical Weathering

Answer 20

(Mnemonics: D,H,O) Dissolution, Hydrolysis, Oxidation

Question 21

areas that are cold and dry tend to have slow rates of chemical weathering and weathering is mostly physical; chemical weathering is most active in areas with high temperature and rainfall.

Answer 21

Climate (More rainfall, increases rate of weathering, the hotter it is the higher rate of weathering)
(if a rock experiences both Hot & Cold Temperatures, and it expands and contracts again and again, this cycle causes the breakdown of rocks, it will exfoliate, and it will get smaller and smaller).

Question 22

• Cold and dry =
• High temperature and high rainfall =

Answer 22

= slow rate of chemical weathering
= high rate of chemical weathering

Question 23

The presence of ______ which is an important chemical weathering agent increases the rate of weathering. High temperature enhances chemical reactions.

Answer 23

Water

Question 24

the minerals that constitute rocks have different susceptibilities to weathering. The susceptibility of minerals (from high to low) roughly follows the inverse of the order of crystallization of minerals in Bowen’s reaction series.

Answer 24

Rock type
Examples: Halite (Rock Salt) is made of soluble materials, hence it will dissolve in water
Limestone can easily be affected by acid, because of it’s composition since it is made up of calcium-carbonate.

Question 25

• Weathering rates roughly follow the inverse of the order of crystallization.
• Temperature is an important factor of mineral formation/crystallization. Olivine crystalizes at high temperature while quartz at the lowest temperature as compared to the other minerals. Therefore, quartz is the most stable on surface conditions (low temperature conditions), while the other minerals in the series would be less stable. Olivine would be least stable. Limestone however will have a high susceptibility to weathering even though it is formed at surface temperature, because it can be easily dissolved by water (Bohol chocolate hills for example).

Answer 25

True

Question 26

rate of weathering is affected by the presence of joints, folds, faults, bedding planes through which agents of weathering enter a rock mass. Highly jointed/fractured rocks disintegrate faster than a solid mass of rock of the same dimension.

Answer 26

Rock structure (if a Rock is massive, it is more intact, hence, it’s not prone to weathering but if a rock has cracks, it is prone to weathering)

Question 27

• The presence of cracks where agents of weathering (water, plant roots, etc.) can enter enhances weathering.
• These cracks/structures facilitate the entry of weathering agents.

Answer 27

True

Question 28

(physical weathering) occurs more quickly on a steep slope than on a gentle one. On a gentle slope, water may stay longer in contact with the rocks, hence chemical weathering is enhanced.

Answer 28

Topography

Question 29

_______ weathering occurs more quickly on a steep slope than on a gentle one.

Answer 29

Physical Weathering

Question 30

Physical Weathering occurs faster when the slope is steep due to the higher slope’s susceptibility to mass wasting and the higher rate at which new materials are exposed to agents of mass wasting (rainwater can easily wash away weathered materials downslope). However, In gentle slopes, the rate of chemical weathering may be higher. This is because water which is an agent of weathering may stay longer in the gentle slopes.

Answer 30

True (The thicker the soil in a place, the higher the rate of WEATHERING, it’s because SOIL will bring more biological activity, and more organism present in an area, it increases also the rate of weathering.)

Question 31

length of exposure to agents of weather determines the degree of weathering of rock.

Answer 31

Time

Question 32

_____ time of exposure to agents of weathering means higher rate of weathering

Answer 32

Longer

Question 33

_____ time of exposure to weathering agents could mean a higher degree of weathering processes have occurred. The rock has been weakened, therefore easier to break.

Answer 33

Longer

Question 34

are internal processes that occur beneath the Earth. These result in reshaping of Earth’s landforms.

Answer 34

Endogenic processes