Geology - Tectonic Theory

Question 1

Evidence of continental drift…

Answer 1

Fossils, geological morphology and how continents fit together.

Question 2

Example of a fossil…

Answer 2

Mesosaurus fossils 300MYA in Africa and South America.

Question 3

Seafloor Spreading

Answer 3

A geologic process where tectonic plates split from each other.

Question 4

Plate Tectonic

Answer 4

Units of lithosphere atop the asthenosphere moving with convection

Question 5

How many tectonic plates?

Answer 5

15-20 tectonic plates that being 7-8 major ones.

Question 6

Types of Plate Boundary

Answer 6

Divergent Boundaries
Convergent Boundaries
Transform Faults

Question 7

Divergent Boundaries

Answer 7

This is movement apart of plates with creation of lithosphere

Question 8

What is a marking feature of divergent boundaries?

Answer 8

Mid-ocean ridges

Question 9

Mid-ocean ridges

Answer 9

Sites of divergence by convection exhibiting volcanism, earthquakes and rifting by tensional forces.

Question 10

What are spreading centres?

Answer 10

Sites of upwelling of magma, creating new oceanic crust.

Question 11

Example of mid-ocean ridge…

Answer 11

The mid-atlantic ridge for example, connects south to other such ridges.

Question 12

Continental rifting

Answer 12

A thinning process of the lithosphere leading to rupture of continents are mid-oceanic ridge formation.

Question 13

Convergent Boundaries

Answer 13

Boundaries where one plate subducts beneath the other due to plate movement.

Question 14

Convergent boundaries in tectonic subduction…

Answer 14

Lithosphere sinking into asthenosphere where mantle convection recycles the material.

Question 15

How do island arcs form?

Answer 15

Lithosphere descends with increasing pressure with depth where water squeezes INTO the asthenosphere, causing mantle above to melt

Question 16

Example of an island arc…

Answer 16

Aleutian Islands

Question 17

Island Arc

Answer 17

A curving chain of volcanic islands occuring around the margin of ocean basins.

Question 18

Interaction of ocean and continental plates…

Answer 18

Continents are less dense so overide oceanic lithosphere, convergence crumpling the subsiding plate, forming mountain belts.

Question 19

How do land-ocean convergence form volcanoes?

Answer 19

Subducting oceanic water melts material with magma rise.

Question 20

Example of a continent-continent convergence zone…

Answer 20

The Himalayas.

Question 21

Transform Faults

Answer 21

A plate boundary along which plate motion is parallel with the strike of the boundary.

Question 22

What forms transform fault?

Answer 22

Sliding of tectonic plates slipping horizontally past one another

Question 23

How does mantle convection result in tectonic movement?

Answer 23

Cold, dense lithospheric plates fall back on their own weight due to gravity.

Question 24

How did pangea split?

Answer 24

Formation acted as an insulation unit, as seafloor spreading was present, where heat was not escaping from the mantle, heat build up occuring forming a mantle plume which bulgus

Question 25

What does lower boundary marks?

Answer 25

Depth of which the plates subduct recycling of the material, about 2,890 km deep.

Question 26

Wilson Cycle

Answer 26

Describes opening and closing of ocean basins and subduction and divergence of tectonic plates during assembly and dissasembly of supercontinents