Lecture 2- The physical environment of the north

Question 1

Why look at geology?

Answer 1

• It forms the basis of the topography
• Provides soil materials and drainage patterns
• Influences species occurrence
• Can influence socio-economics of the north

Question 2

What can the rock type influence?

Answer 2

How the rocks form, where they exist, their chemical composition can provide context for patterns observed (like why there are hills)

Question 3

What are the three types of rocks in the north?

Answer 3

1. Igneous rock
2. Sedimentary rock
3. Metamorphic rock

Question 4

How are igneous rocks formed?

Answer 4

Formed by cooling and solidification of molten rock

Question 5

What are igneous rocks comprised of?

Answer 5

Composed primarily of silicate materials (silicon and oxygen)

Question 6

What are some common types of igneous rocks?

Answer 6

Granite, basalt

Question 7

Igneous rock is the most common ______ material

Answer 7

Parent

Question 8

What type of plants grow on igneous rocks?

Answer 8

Most plants grow on derived soils

Question 9

True or False? Igneous rocks are limiting to plant growth

Answer 9

False (Not limiting and most plants will grow on it)

Question 10

How are sedimentary rocks formed?

Answer 10

• Accumulation of sediment
• Hardening of chemical solutes (iron, phosphate)

Question 11

What are some common types of sedimentary rocks?

Answer 11

Limestone, sandstone

Question 12

Landscapes formed by sedimentary rocks can easily be ______ and can ______ around

Answer 12

• Weathered
• Shift

Question 13

Sedimentary rocks form ______ soils

Answer 13

Calcareous (high in calcium carbonate)

Question 14

What type of vegetation grows on sedimentary rocks?

Answer 14

Favours specialists, calciphyte plants

Question 15

True or False? Sedimentary rocks can limit plant growth and plant diversity

Answer 15

True

Question 16

How are metamorphic rocks formed?

Answer 16

Modifying existing rocks with heat, pressure, mechanical stress (could be modified igneous, sedimentary or other metamorphics)

Question 17

What are some common types of metamorphic rocks?

Answer 17

Gneiss, slate

Question 18

Metamorphic rocks can be favorable for plant growth but depends on ______

Answer 18

The properties of the original rock

Question 19

The type of parent material impacts what?

Answer 19

Can impact the type of soils (textures, draining patterns, chemical leaching) and can impact distribution of plants and animals

Question 20

What is the Canadian Shield?

Answer 20

Refers to large area of exposed precambrian bed rock

Question 21

Describe properties of the Canadian Shield

Answer 21

• Originally large, tall mountains with high volcanic activity
• Now it is relatively flat
• Can be exposed rock with thin soil layer (poor sustainability for agriculture)
• Can be overlain by younger rock and sedimentary
• Very mineral rich
• Rolling topography (has lakes, lots of water on it)

Question 22

What is the interior platform?

Answer 22

Areas that are overlain with younger rocks (giant inland sea deposit)

Question 23

How was the interior platform created?

Answer 23

As the seas receded, it deposited sediments, sealife in weird places

Question 24

Describe properties of the interior platform

Answer 24

• Typically flat lying so flatter topography
• Less lakes cause less/no rolling topography
• More interactions with ground water (peatlands)
• Hydrologic patterns are interrupted
• Vegetation adapted to wetter conditions

Question 25

Where are diamonds most common?

Answer 25

Where basement rock is 1500+ million years old (in areas of exposed bedrock)

Question 26

Oil and gas deposits are deposits of ______

Answer 26

Devonian era fossils

Question 27

What are some ecological impacts of mining?

Answer 27

* Huge rates of habitat loss * Contamination by spills * Disruption to hydrology * Create seismic lines, effects species distribution and how they move around (some trees never grow back)

Question 28

What are some socio-economic impacts of mining?

Answer 28

* Alterations of traditional lands (hunting, sacred land) * Can provide income (often promised jobs, but dont deliver) * Some hunters use the seismic lines to get around * When they leave, they take the economic activity with them

Question 29

Why is everything where it is?

Answer 29

Because of glaciers

Question 30

When was the last glacial maximum?

Answer 30

18,000 years ago

Question 31

What do glaciers change?

Answer 31

Create massive changes in soil, topography, hydrology and species distribution

Question 32

Describe the last glacial maximum (LGM)

Answer 32

* Huge ice sheets * Similar configuration of vegetation zones * Tundra like band south of ice sheets * Conifer forests below tundra * Dry grassland pushed south * Tropics remained stable

Question 33

Describe the glaciers 13,000 years ago

Answer 33

* Ice sheets retreat and separate * Some migration through corridor between ice sheets * Ecozones move back north following the retreating ice * Still cold, harsh, moves back north * Allow species to move between two regions

Question 34

Describe the glaciers 11,000 years ago

Answer 34

* Ice sheets continue to retreat * Huge lakes of melt water pool up against the ice * Laurentide ice sheets scours soil and rock away to expose bedrock (Canadian Shield Pattern)

Question 35

What did proglacial lakes allow?

Answer 35

* Allowed for migration of fish and other aquatic biota * Many populations now separated by dried drainage divides * Facilitated movement of species, development of new species because became isolated

Question 36

What did the proglacial lakes do?

Answer 36

Fed river systems and led to formation of many large lakes (water pooled up against ice)

Question 37

Describe present day glaciers

Answer 37

* Ice sheets restricted to high arctic and high alpine * Vegetation zones are where we are now familiar with them * Continued warming will keep shifting zones north

Question 38

What evidence is there for glaciation?

Answer 38

* Glacial fluting, near borrow Alaska * Glacial moraines * Raised beaches, isostatic rebound * Eskers

Question 39

What is a glacial refugia?

Answer 39

Refers to un-glaciated refuges where species could persist

Question 40

What is the largest glacial refugia in North America?

Answer 40

Beringia

Question 41

What did Beringia allow?

Answer 41

Facilitated movement from Siberia across land bridge