Lithosphere I and II Flashcards

1
Q

What is soil?

A

It is weathered parent material (e.g. rock) that is capable of supporting life.

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2
Q

Describe the major components of soil and their percentages.

A

The soil is 50% solid and 50% pores. The pore space breaks down to 25% air and 25% water (total 50%). The solid space breaks down into 45% mineral particles and 5% OM (total 50%).

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3
Q

Describe the breakdown of organic matter in soil.

A

It breaks down to 80% dead organic material, 10% roots, and 10% organisms

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4
Q

What are mineral particles in soil comprised of?

A

Sand, silt, and clay.

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5
Q

What is the difference between primary and secondary minerals in soil.

A

Secondary minerals are primary minerals that have been broken down and decomposed.

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6
Q

What are the 4 major geological event that shaped Quebec?

A
  1. The formation of the Grenville province
  2. The formation of the St. Lawrence platform
  3. Magma instrusions
  4. Glaciation
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7
Q

The formation of the Grenville province occurred in the […] era. Explain what the Earth looked like at the time.

A

Pre-cambrian. At the time, present-day North America, then called Laurentia, was located near the equator.

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8
Q

Explain how the Grenville province was formed.

A

Laurentia (ancient North America) collided with the Grenville belt, another continental shelf. The heat and pressure formed a very large mountain range called the Grenville mountains.

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9
Q

The Grenville mountains later became […]

A

The Laurentians that we know today.

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10
Q

The Grenville mountains are […] rocks that are high in […] content.

A

Metamorphic, rare mineral

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11
Q

The Laurentian mountain range was formed by […]

A

Erosion

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12
Q

Explain how the formation of the St. Lawrence platform

A

A rift formed in the Grenville mountain range. This caused the Grenville range and Laurentia to split apart, creating the Lapetus ocean. In the Lapetus ocean, marine sediment accumulated along the shore of the Grenville continental shelf. The marine sediments formed limestone beds, which turned into calcium rocks, which became the bedrock of the St. Lawrence platform.

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13
Q

The St. Lawrence platform left […] behind. This occurred through the process of […]

A

Sedimentary rocks, erosion of limestone beds

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14
Q

What is Montreal greystone?

A

It is greystone that comes from limestone from the St. Lawrence linestone beds.

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15
Q

How long ago did the formation of the Grenville province occur?

A

Around 1 billion years ago

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16
Q

How long ago did the formation of the St. Lawrence platform occur?

A

Around 1 billion years ago

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17
Q

How long ago did magma intrusions occur?

A

125 million years ago

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18
Q

How long ago did glaciation occur?

A

35000-10000

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19
Q

The recent geological features are formed from […] and […] events.

A

Depositional and erosion

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20
Q

Is erosion a destructive or a creative force?

A

It is both. It is destructive in that it moves materials to other areas, but it creates new forms with those materials and exposes the materials underneath the original materials.

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21
Q

Is deposition a destructive or a creative force?

A

It is a creative force. It depots materials from geologic event.

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22
Q

Deposition and erosion lay the foundation of the […] of soil.

A

Parent material

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23
Q

What is parent material?

A

It is the unconsolidated mineral or organic material from which the true soil develops.

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24
Q

Describe the third geologic event: igneous intrusions

A

Magma rose from below the Earth’s crust. These underground magma chambers eventually cooled, forming igneous rock. The result was igneous intrusions below the limestone St. Lawrence platform. Since limestone is easily weathered and igneous rock is highly resistant, the igneous intrusions underneath were gradually exposed.

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25
Q

What did igneous intrusions leave behind?

A

The Monteregian Hills, which include Mount Royal, Mont St. Hilaire, Rougement, etc. They are uneroded igneous intrusions where sedimentary rock (limestone) was eroded away.

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26
Q

Explain the fourth geologic event. Include its 3 major consequences.

A

The fourth event was glaciation. Glaciers 2-3 km thick formed, which depressed the crust of the Earth . They:
1. Wore away and levelled the Grenvillian and Monteregian mountains
2. Left behind a trail of stones and rocks and glacial till
3. Created seas (Champlain sea) and deposited clays.

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27
Q

Describe the effect that glaciation has on the landscape.

A

Glaciers picked up rocks, stones, and eroded the landscape as they moved. Then, when the glaciers melt or retreat, this rock is left behind.

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28
Q

Glacial activity left behind […]

A

Glacial till in much of the St. Lawrence lowland, the Hudson bay and northern lowlands and peatlands, and the deposition of Leda clays.

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29
Q

What is glacial till?

A

It is accumulations of unsorted, unstratified mixtures of clay, silt, sand, gravel, and boulders.

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30
Q

Explain how glacial activity left behind the Hudson bay and northern lowlands and peatlands.

A

During peak glaciation, the weight of the glacier caused the Earth’s crust to sink and the mantle to be pushed outward and up. During deglaciation, the crust remains depressed and ocean water and glacial melt filled it. The crust then slowly comes back up, but it is still rebounding - these are the lowlands.

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31
Q

Explain how glaciation left behind Leda clays.

A

After the glaciers melted, water from the Atlantic flowed into the depressed land, forming the Champlain sea. As the crust rose again, the sea water became trapped from entering the ocean. The water eventually retreated and left behind (deposited) thick clay sediments, called Leda Clay.

32
Q

Describe the distinctive characteristic of Leda clay.

A

It is sensitive to disturbance - construction, earthquakes, or stream erosion can liquefy Leda clay and cause landslides.

33
Q

Explain why Leda clay is so structurally unstable.

A

When the Champlain sea was still around, the clay was able to stick together because the saltwater from the Atlantic contains position cations (Ca2+ and Mg2+) that held the negatively-charged clay particles together. But as the salt was gradually washed away by freshwater inputs over time, this left the clay structurally unstable, as the clay particles repel each other.

34
Q

Were the Monteregian hills a consequence of erosion or deposition?

A

Erosion

35
Q

Were limestone beds a consequence of erosion or deposition?

A

Deposition.

36
Q

Is the presence of Leda clay the result of erosion or deposition?

A

Deposition

37
Q

What are the three types of parent material resulting from the glaciers and Champlain sea?

A

Glacial till, marine sediments, and alluvial sand deposits.

38
Q

What are the characteristics of soils formed from Glacial till?

A

The soils contain little organic material and have a high abundance of stones and boulders. They are a clay and sand mixture with good drainage. They also tend to lack nutrients because they are young soils.

39
Q

Explain how the soils from sand deposits were formed.

A

After the glaciers melted, the waves of the Champlain sea sorted the nearby particles by weight. The finest particles, the clay, got deposited elsewhere or stayed in the water. Sand and gravel accumulated on the shoreline.

40
Q

What are the characteristics of soils formed from marine deposits?

A

They are very clay rich soils, coming from the marine beds of the old Champlain sea. They could also be deposited (alluvium) by running river water.

41
Q

What is the annual rate of soil formation?

A

<1 mm per year

42
Q

Describe the process of soil formation after a volcanic eruption.

A

After the eruption, most of the soil around gets covered and eroded. First, lichens colonize the area because they can get nutrients and don’t require soil. Then, they develop the soil until plants can grow on it.

43
Q

Soil formation is also called […]

A

Soil genesis

44
Q

What are the major factors influencing soil formation?

A

CLORPT(H)
Climate, organisms, relief (topography), parent material, time, human activity.

45
Q

How does topography affect soil formation?

A

Soil will typically not form as well on a steep slope vs on a flat field because materials will move downslope. There is often deposition at the bottom of the slope.

46
Q

Soil is formed by […] processes, which act on […]

A

Pedogenic, parent material

47
Q

Name the 4 types of pedogenic processes that can act on parent material.

A

Transformations, translocations, additions, and losses

48
Q

What is addition to soil? Give 2 examples.

A

Addition is when material that was not previously in the soil gets added to it. Ex: plant material, dust after a dust storm.

49
Q

What is translocation? Give an example.

A

Translocation is the movement of material from the surface down the soil profile without leaving the soil. Ex: transporation of clay from the surface to the lower soil profile, tilling soil

50
Q

What is transformation in soil? Give an example.

A

Transformations are typically chemical reactions int he soil. Ex: redox reactions.

51
Q

Explain losses in soil. Give an example.

A

Losses are when a material exits the soil profile. or example, if rain washed sediment down a hill and away from some soil.

52
Q

What are the two main types of parent material? Explain the difference between them.

A

In place: parent material is the same as the underlying bedrock
Transported: parent material is different from underlying bedrock

53
Q

What are the types of in place parent material? Explain the difference between them.

A

Bedrock (residual): parent material formed directly from the underlying bedrock
Organic deposits (i.e. peat): formed in place over a long period of time as organic material gets added and doesn’t decompose, usually in cold and wet environments.

54
Q

What are the types of transported parent material? Explain the difference between them.

A

By gravity (colluvium), by ice (till, outwash), aeolian, by water (alluvium)

55
Q

Explain what colluvium parent material is.

A

It is parent material that has been transported by gravity. You need a hill for this to be possible.

56
Q

Explain what parent material transported by ice is and how to recognize it.

A

It is parent material that has been transported by glaciers (either by glacial till or outwash). It is recognizable in that the sizes of the rocks are unsorted and seemingly random.

57
Q

Explain what aeolian parent material is and give an example.

A

This is parent material that has been transported by wind, such as in a dust storm. An example is loess, which is wind-deposited fine clay and silt.

58
Q

Explain what alluvium is and give 3 examples of how it could be formed.

A

It is parent material that has been transported by water. This could occur when a river dries up and leaves material behind, if there is a flood where water spills over river banks along with the material it contains, or a material could be left behind when water flows from upstream to a flat area, where there’s less energy.

59
Q

Alluvium replies on […] events

A

Deposition

60
Q

How does the parent material turn to soil? Can this process vary?

A

Parent material turns into soil via weathering over a long period of time. The amount of time this takes can vary depending on the type of parent material.

61
Q

Where is most of the colluvium found in Canada?

A

In the Rockies

62
Q

Where is peat most likely to be found in Canada? Why?

A

Northern Ontario, because this is where the glacier was the thickest. it therefore left the biggest indent and led to the formation of wetlands in that area.

63
Q

What is weathering?

A

Any of the chemical, biological, or mechanical processes by which rocks exposed to the weathering undergo chemical decomposition and physical disintegration.

64
Q

Rate of weathering depends on […]

A

Temperature, moisture, organisms, and strength of parent material.

65
Q

Weathering occurs from […] to […]

A

Top, bottom

66
Q

What are the two main types of weathering?

A

Mechanical and chemical

67
Q

What is mechanical weathering?

A

It is the physical breakdown of rocks without changing their chemical composition.

68
Q

What is chemical weathering?

A

It is the breakdown of minerals by chemical reactions with air (or oxidation), acids, or water.

69
Q

What is the most widespread weathering agent?

A

Water (both mechanical and chemical)

70
Q

Give 2 examples of mechanical (physical) weathering.

A

Wind abrasion and freezing/thawing

71
Q

Give 2 examples of chemical weathering. Explain them.

A

Hydrolysis: hydrogen ions react with rock minerals, weakening them.
Dissolution: water with carbonic acid reacts with limestone, pulling its minerals away and into solution to form calcium bicarbonate.

72
Q

Give an example of how organisms can cause chemical weathering.

A

Microbes and plants such as lichens produce organic acids, which dissolve rock and release nutrients for plant growth.

73
Q

Climate affects weathering through […] and […]

A

Temperature, precipitation

74
Q

Describe the relationship between weathering and climate.

A

The wetter the environment (more rainfall), the stronger weathering will be. The warmer the environment will be, the stronger chemical weathering will be (vs) mechanical). Overall, warm, wet climates produce chemical weathering, while cold, humid climates promote physical weathering. Dry climates give low rates of weathering.

75
Q

What is a regolith?

A

It is a layer of unconsolidated materials overlaying the hard, unweathered bedrock.

76
Q

What type of ecosystem do you usually get growing on top of glacial till parent material? Why?

A

Usually, you get grasslands, because soils formed by glacial till are quite young and are therefore nutrient and organic matter-poor.

77
Q

What type of ecosystem do you usually get growing on top of alluvial sand parent material from glaciation? Why?

A

The resulting soil is sandy, as the clay has been transported elsewhere. So, you often get plants that do well on sandy soil, like root crops and some fruit trees.