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Flashcards in The Ocean Basin Deck (23)
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1
Q

What is the composition of Oceanic crust

A

silicate with iron (heavier)

2
Q

What is the composition of Continental crust

A

silicate with aluminum (lighter)

3
Q

What is another name for oceanic crust

A

basalt

4
Q

what is another name for continental crust

A

granite

5
Q

How old is the oldest oceanic crust

A

200 million years

6
Q

How old is the oldest continental crust

A

3.8 billion years (since last rocks were melted)

7
Q

What is the average thickness of oceanic crust

A

7 km

8
Q

What is the average thickness of continental curst

A

40 km

9
Q

What is Bathymetry

A

the topography of the sea floor

10
Q

How much of the Earth surface is covered in water

A

71%

11
Q

What is the mean depth of the ocean

A

3800 m

12
Q

What is the continental shelf

A

gently sloping part of ocean floor adjacent to continent

13
Q

What is the depth the shelf break is at

A

200 m

14
Q

What is the slope of the continental crust

A

2 m for every 1 km traveled

15
Q

What is the continental slope

A

zone between continental shelf and ocean basin

16
Q

what is slope of continental slope

A

70 m for ever 1 km travled

17
Q

What is turbidity

A

Suspended particles that decrease clairty

18
Q

What is the continental rise

A

thick wedge of sediment located at base of continental slope

19
Q

What is the abyssal plain

A

very flat region, has thick layer of sediment

20
Q

What is the abyssal hills and seamounts

A

differs in height above sea floor, usually volcanoes, hills are extinct volcanoes

21
Q

What are the mid ocean ridges and rises

A

volcanic subsea mountains that mark the region of crustal movement

22
Q

What are trenches

A

steep sided depressions that mark where ocean crust is subducted into mantle
deepest part of ocean
often adjacent to volcanic island arcs

23
Q

how do passive continental margins differ from active continental margins

A

passive- gentler slope, no volcanoes

active- steep slope, trench, volcanoes