Geog 1290- Chapter 12

Front 1

What are negative affects of moving plates?

Back 1

1.Cause earthquakes which generates tsunami’s

2.can create volcanos

Front 2

What are some positive effects of moving plates?

Back 2

1.Ash from volcanos creates fertile soil(andisols)

2.Modify chemistry of the atmosphere and it’s greenhouse effect by moving carbon from the atmosphere to the lithosphere and back again over millions of years

3.Build the land which we live on

Front 3

What is the theory of plate tectonics?

Back 3

A theory addressing the origin, movement, and recycling of lithospheric plates and the landforms that result.

Front 4

What is diastrophism?

Back 4

Deformation of the earths crust on a large scale (folding, faulting)

Front 5

What is folding?

Back 5

When the earths crust is pushed up from sides

Front 6

What is Faulting?

Back 6

When tension and compression associated with plate movement is so great that blocks of rock fracture or break apart

Front 7

300 million years ago there was a supercontinent what was it called?

Back 7

Pangaea

Front 8

What ocean surrounded Pangaea?

Back 8

Panthlassic ocean

Front 9

What is the evidence for Pangaea?

Back 9

1.Similar geologic features on coast different continents

2.continents fit together

Front 10

What is the theory of continental drift?

Back 10

A theory proposed by Alfred Wagner stating that continents move slowly across earths surface

Front 11

Who was the first person to propose a theory of continental movement?

Back 11

German meteorologist Alford Lawther Wagner

Front 12

Explain the transition from Pangaea to today’s continental configuration in two steps.

Back 12

1.Opening of the Tethys sea(200million years ago)

2.opening of the Atlantic ocean

Front 13

What to land masses were created by the opening of the tetys sea?

Back 13

Laurasia and Gondwana

Front 14

What is Laurasia?

Back 14

A landmass that resulted when Pangea split about 200 million years ago, which consisted of modern day North America, Greenland, and Eurasia

Front 15

What is Gondwana?

Back 15

Landmass that resulted when Pangea split about 200 million years ago, which consisted of modern day South America, Australia, Africa, India, and Antarctica

Front 16

What was Wagner’s evidence for Pangaea?

Back 16

1.Shape of continents

2.petrologic rock evidence

3.mountain belts

4. Palaeontology

5.Glaciated continents

Front 17

Who was the climatologist who helped Wagner with evidence of glaciated continent?

Back 17

Wladimir Koppen

Front 18

Why was the continental drift theory rejected?

Back 18

1.Earths crust was believed to be too rigid to permit such large scale motions

2.Wagner did not offer a suitable mechanism that could display such word masses for a long journey

Front 19

What was evidence for the plate tectonics theory?

Back 19

1.Detailed map of the ocean floor

2.plate boundaries

3.seafloor spreading

Front 20

What did bathymetric Mapping find an ocean basins?

Back 20

1.Mid ocean ridges

2.seamounts

3.deep-sea trenches

Front 21

What was the significance of mid ocean ridges?

Back 21

These submerge volcanic mountain ranges occur where new oceanic crust is being formed

Front 22

What is the significance of seamounts?

Back 22

The flattops of many seamount indicate that they were one subject to erosion at the sea surface. Later, plate movements carried them into Deepwater

Front 23

What is the significance of deep sea trenches?

Back 23

Deep-sea trenches reveal where oceanic crust dives deep into the mantle in the process of subduction

Front 24

What is subduction?

Back 24

The process in which oceanic lithosphere Bends and dives into the mantle beneath another lithospheric plate

Front 25

What did plate boundaries reveal about earthquakes?

Back 25

Earthquakes occur along lines, correspond with locations of trenches and ridges

Front 26

Who formalize the theory of seafloor spreading?

Back 26

Harry Hess

Front 27

What is the theory of seafloor spreading?

Back 27

New oceanic crust forms at mid ocean ridges and then moves a part

Front 28

What is the evidence for seafloor spreading?

Back 28

1.Palaeomagnetism

2.age of ocean floors

Front 29

What is paleomagnetism?

Back 29

Every 200,000 years, on average, for unknown reasons, earths magnetic field flips.

Front 30

What is the significance of paleomagnetism?

Back 30

These matching magnetic stripes on either side of mid ocean ridges can only be explained if oceanic crust is moving away from mid ocean ridges through time

Front 31

Sediments ______ from the mid oceanic ridges are the oldest

Back 31

Farthest

Front 32

14 (seven primary and seven secondary)

Back 32

14 (seven primary and seven secondary)

Front 33

What is the largest plate?

Back 33

The Pacific plate

Front 34

How do we know where the plate boundaries are?

Back 34

Earthquake activity reveals plate boundary locations

Front 35

How are earthquakes distributed?

Back 35

They occur in geographic pattern that donates the outlines of lithospheric plate

Front 36

What percentage of the worlds earthquakes and volcanos occur along or near boundaries of tectonic plates?

Back 36

80%

Front 37

What is a convection current?

Back 37

A current in a fluid that results from convection (heat transfer in fluids)

Front 38

What three mechanism delineate plate movement?

Back 38

1.Ridge push

2.mantle drag

3.slab pull

Front 39

What is Ridge push?

Back 39

Magma rising along a mid oceanic ridge lifts oceanic lithosphere and forces it apart

Front 40

What is mantal drag?

Back 40

Created by lateral flow of asthenosphere beneath plates between ashetheophere and overlying lithosphere

Front 41

What is slab pull?

Back 41

Weight of subducting portion of plate accelerates plate movement by pulling plate deeper into mantle

Front 42

What percent of plate movement is attributed to slab pull?

Back 42

90%

Front 43

What are the fastest route relative plate movement?How many centimetres per year?

Back 43

Pacific and NASCA plates; 18 cm per year

Front 44

What does the Wilson cycle described?

Back 44

Cyclical opening and closing of ocean basins

Front 45

What is accreted terranes?

Back 45

Massive of crust that is transported by plate movement infused onto the margin of a continent (terrain is too buoyant and fuses instead)

Front 46

What is the wrangellia terrane ?

Back 46

Accreted terrain in the western part of North America

Front 47

What are three types of plate boundaries?

Back 47

1.Divergence

2.convergence

3.transform

Front 48

What is divergence?

Back 48

A region where to lithospheric plates move apart (seafloor spreading, rifting)

Front 49

What is convergent?

Back 49

A region were two lithospheric plates move towards each other

Front 50

What are three types of convergent plate boundary’s?

Back 50

1.Oceanic/ Continental

2.oceanic/oceanic

3.continental/continental

Front 51

What is a transform plate boundary?

Back 51

A region where one lithospheric plates lips laterally passed another

Front 52

What is a rift?

Back 52

A region where continental crust is stretching and splitting

Front 53

What is a rift valley?

Back 53

a linear valley with volcanos formed by rifting of continental crust, sometimes filled with fresh water to form a deep lake

Front 54

What are the most geographically extensive landforms?

Back 54

Mid ocean ridges

Front 55

How many kilometres can oceanic crust be subducted into the asthenosphere?

Back 55

700 km

Front 56

What is partial melting?

Back 56

Magma (made from oceanic crust and the mantle) rises up melting its way through the margin of the continental crust.

Front 57

What is the Pacific Ring of fire?

Back 57

A zone volcanically active mountain chains resulting from some duction on the margins of the Pacific ocean

Front 58

What creates ocean trenches?

Back 58

Oceanic/oceanic plate convergence

Front 59

What is an example of a mountain range with continental/continental plate convergence?

Back 59

Himalaya Mountains

Front 60

What is a continental suture?

Back 60

Joins plate into single new plate

Front 61

What type of earthquakes to transform plate boundary is usually create?

Back 61

Shallow focus earthquakes

Front 62

Most common at mid ocean ridges

Back 62

Most common at mid ocean ridges

Front 63

What is an example of a conspicuous transform plate boundary?

Back 63

San Andreas Fault

Front 64

What is a passive continental margin?

Back 64

A margin of a continent that does not conside with the plate boundary, typically characterized by a broad, sloping continental shelf

-no recent tectonic activity (50,000,000 years)

Front 65

What is a active continental margin?

Back 65

Margin of continent that falls a plate boundary, typically characterized by a deep-sea trench and a narrow continental shelf (adjacent to Alpine belt)

Front 66

What is a hotspot?

Back 66

Location at the base of lithosphere where high temperatures cause overlying crust to melt

Front 67

What is a mantle plume?

Back 67

Mostly stationary column of hard rock that extends from deep in the mantle up to the base of lithosphere

Front 68

How are islands formed at a hotspot?

Back 68

Formed by overlying plates and moving over hotspot

Front 69

What’s a guyots?

Back 69

Crustal motion over a hotspot that produces oh long trail of island and sunken island

Front 70

What do you emperor seamounts indicate?

Back 70

Indicates change direction of movements of plates

Front 71

What are hot Spot tracks?

Back 71

Line of an active volcanos in ocean basins

Front 72

When did the most recent irruption occur in Yellowstone?

Back 72

600,000 years ago

Front 73

How many hot pools and springs are found in Yellowstone national park?

Back 73

Greater than 10,000

Front 74

Where does folding occur?

Back 74

Occurs often where two plates are converging, particularly in regions of subduction and collision

Front 75

What does folding produce?

Back 75

1.anticlins

2.syncline

Front 76

What are anticlines?

Back 76

Fold in crust with an arch like ridge

Front 77

What is a syncline?

Back 77

Fold in crust with a u shaped dip

Front 78

What is inverted topography?

Back 78

When folded surface is eroded by streams, softer rock is often remove more quickly than Harder rock

Front 79

Where does faulting occur?

Back 79

Occurs along zones of weakness and crust , fault zones

Front 80

What is Graben And Horst?

Back 80

Result of tension or extension of rock which leads to the fault block slipping down

Front 81

The East African rift valley is an example of what type of landscape?

Back 81

Graben

Front 82

What are faults scarps?

Back 82

Between gullies are likely to be Reminence of original planes of motion

Front 83

What is orogenesis?

Back 83

Mountain building by any tectonic process

Front 84

What is the orogenic belt?

Back 84

Linear mountain range

Front 85

What is earth longest terrestrial mountain range?

Back 85

Andies(7300 km long)