Chap.8: Mineral Ressources and Geology

Question 1

Earth Formed roughly ____ years ago

Answer 1

4.6 billions years ago

Question 2

Describe how the processes that formed Earth determined the led to distinct vertical zonation.

Answer 2

The early earth was a hot, molten sphere. As this molten material slowly cooled, the element within it separated into layers according to their mass. Heavier elements such as iron sank toward Earth’s center, and lighter elements such was silica floated towards it’s surface. For this reason, the planet is characterized by distinct vertical zonation.

Question 3

What is Earth Vertical Zonation?

Answer 3

If we could slice into Earth, we would see concentric, overlapping layers composed of various materials.
1. The Core: innermost zone composed of iron and nickel
2. The mantle: above the core. Contain magma (molten rock).
3. The asthenosphere: layer on the outerpart of the mantle.
5. Lithosphere: outermost layer, including the mantle and crust.
6. Crust: outermost layer of lithosphere.

Question 4

Are mineral ressources renewable? Why?

Answer 4

No. Earth contains only a finite supply of mineral.

Question 5

In 1912, Alfred Wegener publised a revolutionary hypothesis proposing that the world’s continents had once been joined in a single landmass.
What was the name he gave this landmass?

Answer 5

Pangaea

Question 6

What evidence did he use to support is theory?

Answer 6

1. identical rock formations on both sides of the Atlantic Ocean
2. fossil evidence that a single large continent existed in the past (ie, fossils of the same species now found on continent separated by oceans.

Question 7

What exactly does the theory of plate tectonic states?

Answer 7

The teaory states that Earth’s lithosphere is divided into plates, most of which are in constant motion.

Question 8

What is the tectonic cycle?

Answer 8

The tectonic cycle is the sum of the processes that build up and break down the lithosphere.

Question 9

What are the consequences of plate movement.

Answer 9

1. Continent drift and, as they do, their climates have changed and geographic barriers (ex: mountains) have formed or have been removed.
2. As a result, species evolved and adapted, or slowly or rapidly went extinct.
3. Sometimes, the movement of the plate broke apart continent, creating smaller continent or island (allopatric speciation).

Question 10

Explain how volcanos provide evidence that the plates are in motion.

Answer 10

As a plate moves over a geologic hot spot, heat rom the rising mantle plume melts the crust, forming a volcano: a vent in Earth’s surface. Over time, as the plate moves past the hot spot. ot ca leave behing a trail of extinct volcanic island (ex: Havaiian Islands).

Question 11

Do the math: How long will it take for a plate that moves at 20mm per year to travel the distance of one football field (a football field is 91.44 m long.

Answer 11

time= distance/rate
=91440/20
=4572 years

Question 12

The Richter scale, a measure of the largest ground movement during an earthquake is logarithmic. This mean that, on the logarithmic scale, a value increase by a factor of ___\ for each unit increase.
Thus a magnitude 7 earthquake is ___\ times greater than a magnitude 6 earthquake and ____ greater than a magnitude 4 earthquake.

Answer 12

1. A value increase by the factor of 10 for each unit increase
2. A magnitude 7 earthquake is 10 times greater than a magnitude 6
3. And 1000 time bigger that a magnitude 4.

Question 13

How does rock cycle “recycle” scarce mineral and element.

Answer 13

The rock cycle slowly but continuously breaks down rock and forms new rocks.
Take a moment to review the rock cycle diagram below:

Question 14

Subduction is
(a): The result of a hot spot moving near a plate boundary
(b): occurs when one plate passes under another
(c): occurs when oceanic plates diverge and form volcanoes
(d): is the process in transform boundaries that results in earthquakes.

Answer 14

The answer is (b).

Question 15

Explain how soil is formed

Answer 15

Soil is the result of physical and chemical weathering of rocks and gradual accumulation of detritus from the biosphere over hundreds of thousands of years.

Question 16

what are the soil horizons?

Answer 16

As soils form, they develop characteristic horizons, which are horizontal layers with distinct physical features such as color or texture. From the surface, they are labelled O,A,E,B,C

Question 17

All soil have horizons, whci vary depending on soil forming factors such as…

Answer 17

1. climate, organisms and parent material.
2. Another factor to consider: as the soil been mixed? Most soil have a O or a A horizon, but usually not both (in a soil that is mixed, the toplayer is called topsoil and correspond to the A horizon).
3. And another factor to consider: is the soil acidic: Some soils that have an O horizon also have a E horizon (a zone of leaching found in acidic soil).

Question 18

why is soil important?

Answer 18

⇨ medium for plant growth
⇨ carbon storage
⇨ filters water
⇨ habitat for organisms
⇨ breaks down organic material and recycled nutrients.

Question 19

Weathering: 2 general types.

Answer 19

physical weathering is the mechanical breakdown of rocks and mineral caused by water, wind or variation of temperature. biological agent can cause physical weathering (ex: roots of trees)
**chemical weathering **is the breakdown of rocks and minerals due to chemical reaction, the dissolving of chemical elements from rocks, or both.

Question 20

erosion

Answer 20

transport of weathered rock fragments by wind, rain carried to new location and deposited.

Question 21

The processes that form soil work in 2 directions simultaniously. Describe the process soil formation “from below”.

Answer 21

The breakdown of rocks and primary ineral by weathering provides the raw material for soil from below.

Question 22

Describe the process of soil formation “from above”

Answer 22

The deposition of organic matter form organisms and their wastes contributes to soil formation from above.

Question 23

Factors (5) that determine soil properties

Answer 23

1. parent material
2. topography
3. climate
4. soil organisms
5. time

Question 24

What is parent material?

Answer 24

A soil’s parent material is the underlying rock material from which it’s inorganic components are derived.

For exemple: a **quartz sand **(made of silicon dioxide) parent material will give rise to a soil that is nutrient poor. A soil that has calcium carbonate as it’s parent matieial will contain an abundant supply of calcium, a high pH, and ay also support high agriculture.

Question 25

effects on soil formation topography

Answer 25

Soil form on steep slope are constantly subjected to erosion.
Soils that formed at the bottoms of steep slopes continually accumulate material from higher elevation and can become quite deep.

Question 26

Effects on soil formation: climate

Answer 26

warmer climate = faster breakdown of organic matter
more precipitation = more weathering, erosion and deposition

Question 27

effects on soil formation organisms

Answer 27

plants removed nutriants and excrete organic acid (which cause weathering).
Animal tunnels and burrow and in the process mix the soil and distribute organic and mineral matter.
Soil organism recycle the soil matter in a way that is beneficial to plants.
Human use and overuse of land lead to soil erosion (plowing), compaction (heavy machinery), Intenive irrigation can deple soil of nutrients and application of pesticides pollute the soil.

Question 28

What is Soil degradation

Answer 28

the loss of the ability to support plant growth.
Human activities such as agriculture and forestry has led to significant soil degradation. A major cause of soil degradation is soil erosion by plowing.
It takes century for topsoil to be replaced.

Question 29

Describe the cause of soil compaction and it’s consequences.

Answer 29

compression of soil by machines (tractors) grazing, lifestock (cows), and humus reduces ability to hold moisture
- dry soil erodes more easily
- dry soil supports less plant growth, less root structure, leading to more erosion

Question 30

Describe nutrient depletion and it’s consequences

Answer 30

repeadingly growing the same crops on the same soil removes key nutrients (N, P, K, Na, Mg) over time
- reduces ability to grow future crops

Question 31

To understand and classify soil types, we need to understand the ___, ___ and ___\ properties of soil

Answer 31

1. physical
2. chemical
3. biological

Question 32

The relative abundances of sand, silt and clay in a soil determine its ____, which in turn determine soil ___

Answer 32

texture
permeability

Question 33

What is permeability and why does it matter

Answer 33

The permeability of a soil describe how quickly soil drains. How quickly a soil drain depend on it’s texture.

Sand, with it’s large, loosely packed particles, drains quickly. Clay- whose small particles can pack together much more tighly than sand particles, drains much more slowly. Silt particle are intermediate both in size and in capacity to retain water.

The best agricultural soil is a mixture of sand, silt and clay (loam), which promotes a balanced between water drainage and retention.

Question 34

Describe the chemical properties of soil with lot’s of clay.

Answer 34

Clay particules have a negative electrical charge. The negative electrical attracts positively charged minerals ions (cations). Clay helps maintains these cations near the surface, where they can better be access by plants.

Question 35

The ability of a soil to adsorb and release cations is called it’s ____ ___ ____, sometimes referred to as the **nutrient holding capacity. **

Answer 35

Cation exchange capacity

Question 36

Why are soils with a high cation exchange capacity (CEC) better for agriculture?

Answer 36

Soil with high CECs have the potential to provide essential cations to plants such as calcium (Ca++), magnesium (Mg++) and potassium (K+).

Question 37

Soil acids are generally detriental to plant agriculture. Soil base can neutralize or conteract soil acids such as aluminium and hydrogen.
What elements are consider “soil bases?

Answer 37

1. Calcium
2. Magnesium
3. potassium
4. sodium
   All of these except sodium are important plant nutrient.

Question 38

The overall CEC of a soil is a function of the amount and types of clay particles present. However, soil that are more than 20% clay is problematic. Why?

Answer 38

A soil with 20% or more clay has low permeability and therefore can become waterlogged. In waterlogged soils, plants roots are deprived of oxygen.

Question 39

Who are the organism populating the soil.

Answer 39

Bacteria, fungi and protozoans account for 80 to 90% of soil organism. Also present: snails, slugs, insects, earthworms and rodents.

Question 40

What do the living organism contribute the soil?

Answer 40

1. Soil mixing
2. Breaking large organic material into smaller pieces
3. Contributes to humus formation (earthworm)
4. Eat the plants and their roots (looking at you, slug!)
5. Consume dead plnanmt and animal tissues and recycle the nutrients they contain.
6. Lastly, some soil bacteria also fix nitrogen, which is enssential for plant growth.

Question 41

lithosphere

Answer 41

thin, brittle layer of rocks that includes solid upper mantle and crust (tectonic plates)

Question 42

subduction

Answer 42

The oceanic plates, which has a higher density, is slide under the continental plate.

Question 43

Strip mining

Answer 43

A surface mining technique where “strips” of soil and rock are remove to expose ore. It is used when the ore is relatively close to Earth’s surface and runs parallel to it, which is oftern the caes for deposit of sedimentary material, like coal and sand.

Question 44

Mine tailings

Answer 44

Unwanted waste material created during mining including mineral and other residues that are left behind after the desired metal or ore is removed. Mine tailing can be return to the hole created during the mining process - which is one strategy to restore the mined area to something close to it’s original condition.

Question 45

Open-pit mining

Answer 45

A surface mining technique that creates a large visible pit or hole in the ground. Is used when the resource is close to the surface but extens beneath the surface both horizontaly and vertically. Copper mine are often open-pit mine.

Question 46

Mountaintop removal

Answer 46

A surface mining technique in which the entire top of a mountain is removed with explosives. Large earth-moving equipment removes the ressource and deposits the tailings in lower elevations regions, often near rivers or streams.

Question 47

Placer mining

Answer 47

The process of looking for minerals, metals, and precious stones in river sediments.

Question 48

Subsurface mining

Answer 48

Mining techniques used when the desired resource is more than 100 m below the surface of the Earth.

Question 49

Does mining affect air quality? How?

Answer 49

Yes. With surface mining, Air quality is compromised by the dust from earth moving equipment.
With subsurface mining, the emission from fossil fuels use to power mining equipment can be significant.

Question 50

How does mining impact water quality.

Answer 50

Water get’s contaminated as it percolates through tailings.
Surface and surface water runoff in certain location can contain high concentrations of toxic metals and acides.

Question 51

Describe the effect mining has on biodiversity

Answer 51

Surface mining contributes to habitat alteration and destruction. Subsurface mining require building road, which fragment habitat. Consequently, certain native species may decrease.
However, when restoration is done properly, it is possible to see an increase in native species.

Question 52

Can mining make miner sick?

Answer 52

Yes, indirectly in the case of surface mining (see effect on water and air quality).
Subsurface mining comes with occupational hazards such as death and chronic respiratory disease.

Question 53

Describe what occurs at a divergent plate boundary

Answer 53

Two tectonic plates move away from each other. As magma from the mantle reaches Earth’s surface and pushes upward and outward, new rock is formed, a phenomenom called seafloor spreading.

Question 54

Seafloor spreading creates new ____ and brings important elements to the “surface” such as copper, lead, silver.

Answer 54

Lithosphere. Since the new rock typically lies under the deep ocean some of that material is hard to access.

Question 55

Describe what occurs at a convergent plate boundary

Answer 55

When two tectonic plates move toward each other. If the collision happen between 2 tectonique plates are of the same density, it can create mountain range such as the Hymalayas.

Question 56

What happens at a transform plate boundary?

Answer 56

When two tectonic plates slide past each other. Causes earthquakes.

Question 57

Mineral

Answer 57

A naturally occurring, inorganic solid that has a crystal structure & a definite chemical composition

Question 58

Ore

Answer 58

A rock that contains a large enough concentration of a mineral making it profitable to mine

Question 59

Reclamation

Answer 59

A process in which mined land must be recovered with soil and replanted with vegetation - returning land to its original condition

Question 60

Steps involve in reclamation after mining.

Answer 60

1. The mining company must fill in the hole or depression it has created in the landscape.
2. The fil material must be shaped to follow the original contours of the land that existed before the mining began.
3. Prior to beginning mining operations, the minig company usually scrape off the topsoil and put it aside. The topsoil will be returned and spread over the landscape after mining is completed.
4. The land must be replanted with vegetation native to the area.