Western Cordillera

“Geology”

3 Rock Types!

- Metallic Minerals: found in igneous rock. Ex. iron + silver
- Non-Metallic Minerals: some metamorphic and sedimentary Ex. potash + asbestos + mica
- Energy Minerals: California = offshore. Utah + Colorado = oil shale. Ex. Petroleum, coal, natural gas. 

1848-1849: Gold Rush in California. (49ers!)

1890’s: Klondike Gold Rush in Yukon. 

When the Western Cordillera was being settled, the mountains made land transport very difficult for Europeans. 

“Terms 2 Know”

- Pass: A continuous gap through a mountain range. Example: the Rogers Pass. A pathway through the western cordillera necessary for transport. 
- Intermontane Basin: Area of lower elevation between the Rocky Mountains on the east and the Coats Range on the west. Basin is between two mountains. 
- Plateau: A large, relatively high and level landform. An elevated plain in the western cordillera. 
- Fiord: A drowned valley at the coast that has been carved by glacial ice. Coastal areas. A triangle like shape that has been cut out of the coast. Ex. BC. 
- Temperature Range: The difference between the warmest and coldest temperature during a certain time. Difference between highest and lowest temperatures during a month. 
- Salinization: The accumulation of soil salts in the topsoil as heat evaporates soil moisture. 
- Lithosphere: The solid rock portion of the earth’s crust
- Mantle: The semisolid layer of rock just below the lithosphere.
- Plate(s): The immense slabs of the earth’s crust that move on top of the mantle.
- Flash Flood: Sudden flood usually due to very heavy and sudden rainstorms. Occurs in areas of low relief, and low precipitation, because the soil is hard. Occurs in the south-central. 
- Fault: A fracture in the earth’s crust along which ether vertical or horizontal movement takes place; violent movement is called an earthquake. Weakness in the earth’s crust. 
- Subduction: the process of thrusting an oceanic plate into the mantle. Tidal wave + mantle displaced travels up through fault and creates a volcano. West coast: large subduction earthquake expected. Subduction earthquake is when the plate springs back. 
- Volcanism: the process of creating a volcano. Molten material is forced to the surface where gasses and pressure is released, forming volcanoes. 
- Cinder cone volcano: a cone built of cinders and ash only. 
- Shield Volcano: a cone composed primarily of lava flows.
- Composite volcano: a cone built of ashes, cinders, and lava.
- Earthquakes: the breaking or sudden movement of rocks in the lithosphere that produces shock waves at the point of or along the fault line. 
- Fault Lines: the line between two tectonic plates; a fault. 
- Talus / scree: an accumulation of loose rock fragments that have fallen to the base of a slope from which they were weathered. 
- Abrasion: wearing away of rock surfaces by small particles of rock carried by water, wind, or ice. 

“Western Cordillera”

- Geographically very diverse
- Highest point in North America is Mt McKinley in central Alaska
- Highest point in Canada is Mt Logan in south-west Yukon
- Lowest point in North America is Death Valley in California at 90m below sea level.

Almost every type of climatic conditions exist in the Western Cordillera

- Snag, Yukon. –81 C
- Areas that do not experience temperatures below 0. 
- Areas that are continuously snow covered. 
- Very dry, desert conditions
- Very wet rain forests. 

Mauna Loa: - world’s largest mountain
        - shield cone volcano
Climate: 3 Patterns of Temperature

1. North-South:

- Go up in latitude, there is a drop in temperature. 
- Latitudinal position: 1.  Angle of sun’s rays 2. Surface area 3. Amount of atmosphere the rays have to travel through. 

2. East-West:

- Ocean (west) moderates temperature
- Temperatures tend to be much warmer and colder in the interior. They are influenced by land masses, rather than by the ocean.  

3. Elevation

- Environmental lapse rate: 6.4 C / 1000m

Contour map: shows elevation points. Lines can be 20m apart. 
Isotherms: connect lines of same temperature on a climatic map. 
“Precipitation Patterns”

1. Elevation:
- As elevation increase, precipitation increases, up to a certain point
- Cooler temperatures cause increased condensation

2. East-West:
- Precipitation levels are greatest in the west and generally decrease as one moves eastward in the WC. 
- This is because of the proximity to the ocean and the influence of the mountains. (Orographic precipitation and rain shadow). 

3. North-South
- Driest area is the extreme south-west but there is no general pattern of precipitation levels as one moves northward. 

“3 Types of Volcanoes”

1. Cinder Cone: 

- layers of cinder and ash
- falls down and sticks
- steep sided
- Mt. Peracutin (Mexico)

2. Shield Cone: 

- formed entirely of lava
- gently sloping; magma flows and cools slowly
- Mauna Loa (Hawaii)

3. Composite Cone 

- formed by layers of cinder, ash, and lava
- usually very large 
- Mount St Helens

“Mountain Building”

Lithosphere: the earth’s thin, brittle, outer crust. Subjected to “tectonic forces”. 

Tectonic Forces

1. Folding  
2. Faulting  
3. Volcanic Activity

Mantle: Unstable! Divided into plates like an eggshell or puzzle. 

Caldera:

- Pipe gets plugged
- Spews out, portion gets blow off
- Caldera is what’s left after chunks blow off

Note: Composite volcano is usually the largest. 

“Faults”

Normal Fault: The land on either side of a single fault can either rise or fall. When the forces pull apart, a normal fault occurs. This creates an escarpment. 

Thrust fault: If the tectonic forces push towards each other, thrusting occurs. One block of crust rides up and over the other block. Ex. Rocky Mountains

Rift Valley: Where two faults occur, and tectonic forces are pulling the crust apart, the block of crust between the faults drops, causing a rift valley. Ex. Death Valley and Rocky Mountain Trench.

Block Mountain: Where two faults occur, and tectonic forces are pulling the crust apart and pushing the center block upwards, a block mountain forms. Ex. Mountains in Utah and Coast Range of California.	

“Earthquakes”

- Movement of plates. 
- Earthquakes common between 2 tectonic plates. 
- Fault lines : weakness in the lithosphere
- Epi Center : point where the quake originates and the quake is most severe
- Richter Scale measures the intensity of earthquakes
- San Andreas Fault : a major fault line in California that runs from LA to an area north of San Francisco. 
- Subduction Quake : land snaps back. Huge tidal wave if along coats. The coastal plate gets pushed under the continental plate. 

“Shaping Forces”

1. Glaciation : fiords – drowned valleys
2. Water Activity : depends on type of rock.  2 Factors: velocity and quantity of water
3. Wind Movement : like sand blasting!
4. Chemical Processes : oxygen combines with certain elements to break down rock. Also mineral salts corrode rock in dry areas. 
5. Gravity : loose rocks get pulled down, brings down other rocks, crumbles. 
6. Vegetation : roots invade cracks in rocks and enlarge cracks. Mosses and lichens slowly weaken rock. 
7. Soil and Rock Movement : landslides ; soil, gravel, rock. Rock gives way : results in Abrasion! 
8. Temperature: heat + cold. 

Western Cordillera

P.114 Questions

8. The Rocky Mountains are very close to the coats line, thus exposing only a small strip of land to the oceanic climate, while sheltering the rest of the continent, causing a continental climate. Also, the air masses, must pass over Vancouver Island, which causes fluctuations in the temperature when changing from water to land mass. 

9. Define: Smog is made up of smoke and fog. Climatic factors, topographic conditions, and urban activities often combine to form a kind of pollution – smog. When the pollution, smog, is contained in urban centers, the problem is hazardous. 

10. The San Bernadino Mountains to the north and east almost enclose the LA Basin. Descending air in high pressure cells creates a temperature inversion. Warmer temperatures in higher altitudes, for an average of 340 days a year. This acts as a lid, trapping the exhausts and industrial gases below. The smog can’t rise nor move inland. This reduces visibility and creates respiratory problems. 

Quake Hunters Proof

1. Ohiaht people legend
2. “Muddy footprint”: sand layer, distinct colors left by a tidal wave
3. Drowned forest
4. Cascadian subduction zone
5. “Orphan” tsunami – 1700 January 26 in BC because of the international date line. Records kept, Shogun’s rice destroyed. 
6. Tree rings and carbon dating: tree rings in the roots. 

- 1964 Anchorage, Alaska > subduction quake measured 9.2 on Richter scale. 

Seismograph

- record the “waves” produced by quakes. 
- P Wave: primary
- S Wave: secondary – most damaging
- 7.2 to 8.2 is 10X more damaging. 7.2 to 9.2 100X!