Lecture 16

Question 1

Relief

Answer 1

Shape of land, more specifically, the elevation difference between highest and lowest point in area.

Question 2

Orders of relief

Answer 2

Different scales.
1st order - broadest scale. Continents and ocean basin. Largest landforms.
2nd order - major features of first orders (mountain ranges, plains).
3rd order - individual landforms (a valley, a beach).

Question 3

2nd order in ocean basins

Answer 3

Mid ocean ridge (underwater ocean range).
Abyssal plains (most of ocean floor).
Continental margin; continental rise (gentle rise up from deep sea floor), continental slope (steeper rise), continental shelf (gentle rise, continent merges with ocean basin).

Question 4

2nd order of relief on continents

Answer 4

Mountain chains (actively growing). Mountain roots (not active wearing down). Shields (tectonically quiet, relatively flat). Exposed shields (bedrock at surface). Covered shields (covered by sediment).

Question 5

Continental drift

Answer 5

When accurate maps were map, a jigsaw fit of continents became apparent. Matching fossils were found and rock types and mountain ranges match up.

Question 6

Alfred Wegener

Answer 6

Took fit of continents seriously and sought an explanation. Suggested that continents once were together; Pangea.

Question 7

Paleomagnetism

Answer 7

Shift in magnetic poles occurs; now north, other times south.

Question 8

Sea floor spreading

Answer 8

New material created in mid-ocean ridges, then moves away to both directions. Showed that crust does move around and that Wegener was correct.

Question 9

Convection cells in asthenosphere/mantle

Answer 9

The leading theory of movement. AKA the plastic/moving layer.

Question 10

Divergent plates

Answer 10

Plates move away from each other and a new crust is created.
Mid ocean ridges, ocean basins grow, Rift Valley; beginning of ocean.

Question 11

Ocean-continent convergence

Answer 11

Oceanic plates and continental plates hit.

Continental crust is less dense, so stays on surface, oceanic crust sub-ducted.

Question 12

Continent-continent convergent

Answer 12

Continental crust crumbles to form mountains.

Question 13

Ocean-ocean convergent

Answer 13

Two oceanic plates meet. Subduction causes melting, some magma rises, causing volcanoes of continental margin.

Question 14

Transform faults

Answer 14

Two plates slide past each other.
Can cause earthquakes.
Common on mid ocean ridges, some on continents.

Question 15

Terranes

Answer 15

Mini plates that join up with major plates.

Question 16

Pangea

Answer 16

Wegener suggested the continents were tougher in a supercontinent called Pangea.

Question 17

Laurasia

Answer 17

When Pangea broke up, the North was called Laurasia.

Question 18

Gondwanaland

Answer 18

When Pangea broke up, the South was called Gondwanaland.