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Flashcards in Chapter 2 Deck (80):
1

In the Southern Hemisphere ... Of the total area is ocean

80%

2

Four large basins

Pacific, Atlantic, Indian, arctic

3

What is the oldest and deepest

Pacific

4

How long do scientist believe earth originated

4.5 bill. Years ago Big Bang THEORY
13.7 Big Bang
3.5 organisms

5

What is an essential element to sustain life

Location relative to sun allows water to stay liquid

6

Core

Innermost layer, solid inner core liquid outer, iron rich magnetism

7

Mantle

Middle layer , semi plastic

8

Crust

Outermost layer , thinnest portion

9

Oceanic crust

Basalt , denser than continental

10

Continental

Granite, construction mainly, less dense than oceanic

11

Oceanic v. Continental

3.0 density, 2.7 g/cm^3
5 km 20 to 50 km thick
Young old
Dark light
Iron, magnesium / sodium potassium calcium aluminum

12

Continental drift was proposed in and by

1912 Alfred wegner
Single supercontinent Pangea

13

When did Pangea break up

180 mill. Years ago

14

Why was it not widely accepted

Not explain how

15

Main features of plate tectonics

Covered by crustal plates
Constantly moving spreading in center and sinking at edges being regenerated
Convections currents assist movement
Heat from mantle drives currents

16

Mid oceanic floor rise from ... What are they

Ocean floor , submarine volcanic mountains

17

What is ridge displaced by

Faults in earths crust called transform faults

18

Where is very little sediment located and what does it mean

At bottom near mid ocean ridge, not old

19

Where does sediment get thicker

Farther away from ridge, older, sediment has had time to accumulate

20

At random intervals earth's magnetic field..... New rock formed from... Record the orientation of earths ..... at the same time ... Cools

Reverses , magma , magnetic fields, magma

21

Studies of sea floor records stripes of.... That are ..... To the mid ocean ridges. This is evidence of

Alternating magnetization, parallel, continuous formation of new rocks at ridges

22

As new rocks are formed

Olde dis pushed away forming patterns

23

Chains of islands are found throughout oceans especially in

Pacific, island arcs

24

Island arcs are situated along what? No on which side

Deep sea trenches, continental side , other side is sub ducted

25

Underneath the earth's crust is a layer of

Heated rock driving creation of new ocean floor

26

Pangea was surrounded by single world ocean

Panthalassa

27

What sea separated Eurasia from Africa

Tethys

28

How long ago were Panthalassa and Tethys in place

200 mill.

29

180 mill. Years ago a rift formed between

North America and South America +Africa

30

What two continents were formed form Pangea

Laurasia and Gondwana beginning of mid Atlantic ridge

31

Split up Gondwana

Indian ocean formed

32

How long ago did rift between soutbamerica and Africa form

135 mill. Joined mid ocean ridge in North Atlantic to form one single mid Atlantic ridge

33

As the Atlantic Ocean grows the Americas are carried farther away from

Eurasia and Africa

34

Atlantic Ocean ... And Pacific Ocean ....

Grows, shrinks

35

Lithogenous sediments

Derived from break down of rocks weathering

36

Biogenous sediments

Derived from skeletons and shells of marine organisms

37

Biogenous sediments can reveal

Info from the past

38

Ocean temp. at time microfossils were formed can be determined by ratio of

Magnesium to calcium
Different ratios of oxygen isotopes

39

Margins of continents are boundaries between

Continental and oceanic crust

40

Boundaries consist of

Continental shelf landward
Slope
Rise seaward

41

Continental shelf makes up ... Oceans surface area , biologicallyis the

8% richest area of ocean

42

What is the width of the continental shelf, where is shelf break

1 km to 750, 120 - 400 m

43

Slope is the ... Of the continent , begins at ... And continues to...,mint is the .... Part

Edge , shelf break deep sea floor , steepest

44

Rise is formed by what

Sediments that have been pushed down to continental shelf and slope, underwater river delta

45

Passive margins

Geologically inactive , flat wide coastal plains , wide continental shelves , gradually sloping slopes

46

Example of passive margins

East coast of us

47

Active margins

Intense geological activity , earthquakes volcanoes trenches , steep rocky shorelines, narrow continental shelves , steep continental slopes

48

Example of active margins

West coast of us

49

Where were similar fossils founded

South America and Africa

50

Rock types were found similar in

North America and Europe, Madagascar and India

51

Coal deposits from tropical plants on artcic islands

Northern continents once occupied tropical latitudes

52

Alfred Holmes what year

1928 circular convection currents of molten material provide ample force to divide and move continents

53

Late 1960's theory of

Plate tectonics .., technology floor was not essentially flat
50000 km long ridges and 11 km deep trenches

54

Detected pattern of

Alternating magnetic polarity emanated from ridge tops

55

Volcanic activity and island building occurs most at

Trenches

56

Who came up with sea floor spreading

Harry Hess and Robert dietz

57

Divergent boundary

Mid ocean ridges , two plates move away making break or rift , magma rises up making new crust

58

Convergent boundary

Two plates moving toward each other meet , denser subducts , if both made of continental very little subducts
Instead they buckle and form valleys, ridges, high mountains

59

Transform boundary

Plates slide along each other in opposite directions
When they get stuck there is a build up of tension , released in earthquake form

60

What are most geologically active

Zones along plate boundaries

61

Earthquakes are common among what types of boundaries

All boundaries

62

Volcanoes are associated with what type of boundaries

Divergent and convergent

63

Well known plate boundaries that encircles Pacific Ocean and has frequent earthquake and volcanoes is called

Ring of fire

64

Hot spots

Magma burns through as plate is moving

65

What is an example of a hotspot

Hawaii

66

Topography is the study of .

is the study of Earth's surface features, for the purposes of this activity, it specifically involves the recording and study of the planet's relief or terrain above sea level.

67

Bathymetry is


study of Earth's underwater features for the purpose of this activity, it specifically involves the recording and studying of the planet's water depth below sea level.

68

What changes because of typography and bathymetry

Latitude, longitude, elevation, depth

69

Where is mt. Everest

Eastern Nepal, border of Tibet, Himalayan mountain range

70

What was mt. Everest named after and what year

Sir George Everest British surveyor general of India
1865

71

Lowest ocean depth is called and where is it

Challenger deep beneath western Pacific Ocean , Philippine sea in southern end of Marianna's trench

72

What was challenger deep named after and when

British survey ship challenger II which surveyed trench in 1951

73

Other names for Everest

Chomolungma -Tibetan
Sagarmatha- Nepalese
Deodungha- local area Nepalese
Shengmu feng- simple Chinese

74

Lowest ocean depths is how far from highest peak

6325 km southeast

75

In the northern hemisphere... Total area is ocean

61%

76

What two types of structures are found at subduction zones

Volcanoes trenches

77

What causes trench to form

One plate sinks beneath another

78

Geologic process at mid ocean ridge

Volcano and earthquake

79

Black smokers result from

Minerals

80

Where can we find island arch along trench

Aleutian Islands