4 Geology of Cordillera

Question 1

What is the elemental makeup of the earth? (5)

Answer 1

Iron (32.1%), Oxygen (30.1%), Silicon (15.1%), Magnesium (13.9%), and other (8.8%)

Question 2

What layer of the earth that flows?

Answer 2

Asthenospheric mantle

Question 3

What are the two types of lithosphere? And what is the thickness and density?

Answer 3

continental, granitic crust, ~150 km, less dense
Oceanic, basalt crust, ~7-100 km, more dense

Question 4

What are the three ways heat flows from the earth?

Answer 4

Conduction: Moving from hot to cold
Convention: Magma moving to the surface (slide 13)
Advection: From a volcano

Question 5

What is the force driving plate movement?

Answer 5

Convection traction

Question 6

See slide 16-19 shows different kinds of subduction

Question 7

What is the Ring of Fire?

Answer 7

Refers to active volcanos on the pacific plate

Question 8

Where is the Intermontane belt?

Answer 8

West of the omenica belt

Question 9

What are kind of rocks types are in the intermontane belt?

Answer 9

Mostly volcanic and sedimentry rocks, and is very complex

Question 9

What are the physiographic regions in the intermontane belt? (4)

Answer 9

Yukon Plateaus, Stikine Plateaus, Skeena Mountains, and Interior plateaus

Question 10

What is the metamorphic grade in the intermontane belt?

Answer 10

Mostly low grade metamorphism

Question 11

What is the origin of the intermontane belt?

Answer 11

Exotic terranes

Question 12

What kind of metamorphism occurs in the intermontane belt?

Answer 12

Accetionary prism (Med. pressure, med. temp.)
Collisional mountain belt (High pressure, low temp)

Question 13

Define exotic terranes?

Answer 13

A tectonostratigraphic terrane is a fragment of
continental or oceanic crust formed on, or broken off
from, one tectonic plate and accreted (sutured) to the
crust lying on another plate. The crustal fragment
preserves its own distinctive geologic history, which is
different from that of the surrounding areas

Question 14

What did the intermontane belt start out as?

Answer 14

Volcanic islands (island arc)

Question 15

How many terranes are within the intermontane superterrane?

Answer 15

6

Question 16

What important mountain is within the coast belt?

Answer 16

Mount Logan is in this range

Question 17

What are the physiographic regions in the coast belt? (2)

Answer 17

St. Elias Mountains, and Coast Mountains

Question 18

What is the main rock type in the coast belt?

Answer 18

Mainly jurassic to cenozoic granitic rock (80%)

Question 19

What’s the metamorphic grade in the coast belt?

Answer 19

Granite mostly, there’s also contact metamorphism

Question 20

What is the coast belt’s structural style?

Answer 20

Complex

Question 21

What is the Stawamus Chief?

Answer 21

The great cleft in the mountain’s cliff face in the Squamish area

Question 21

What is the physiographic regions are in the insular belt? (2)

Answer 21

St. Elias Mountains, and the insular mountains
Mount Logan straddles this and the coast belt

Question 22

What rock types are in the insular belt?

Answer 22

Terrane rock (mostly Wrangellia) volcanic, some plutonic, and sedimentary
sedimentary rocks

Question 23

What is the metamorphic grade in the insular belt?

Answer 23

Mostly low-grade metamorphism

Question 24

Where do the sedimentary rocks in the insular belt mostly exist?

Answer 24

Sedimentary rocks are mostly found on the east side of the insular belt near Nanaimo

Question 25

What is interesting about the faults in the insular belt when compared to the other belts?

Answer 25

The faults point in the opposite direction to all the belts

Question 26

What is the origin of the Insular belt?

Answer 26

Exotic terranes

Question 27

What are the terranes within the insular superterrane?

Answer 27

Alexander terrane
Wrangelia terrane

Question 28

What is the opposing theory of the origin of the insular belt?

Answer 28

It is believed that its insular belt came from the Baja saying that zircon grains from Vancouver Island and the southwestern United States matched (see slide 113), there is also strong fossil and paleomagnetic evidence

Question 29

What does paleomagnetics tell you about a rock?

Answer 29

The magnetic signature of igneous rocks can indicate their latitude when they form