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Flashcards in Exam 2.2 Deck (23):
1

What is bathymetry

The measurement of depth of water in oceans, seas, or lakes

2

What tools are used in bathymetry?

- submarines
- remotely operated vehicles
- satellites

3

What are the 3 parts of the continental margin?

- continental shelf
- continental slope
- continental rise

4

What is an ocean basin?

- an area of ocean floor between continental margins

5

What is a continental margin?

The shallow water found in proximity to the continent

6

What is the difference between continental shelf at active margins and at passive margins?

Passive margins: broad continental shelves
Active margins: narrow shelves

7

What are the passive margin characteristics?

- no earthquakes or volcanoes
- plate moves away from mid atlantic ridge
- gentle slopes, no trenches
- wide shelves

8

What are the active margin characteristics?

- mountainous
- narrow shelves
- trenches

9

What is a continental slope?

- extend from shelf to rise
- ranges from 1 km to 10 km

10

How do continental rises form?

Sediment builds up from
- turbidity currents
- underwater landslides

11

What are hydrothermal vents?

An opening in the sea floor out of which heated mineral water flows

12

How do hydrothermic vents form?

- sea water drips into ocean crust through spreading centers or subduction zones
- cold sea water is heated by magma, and reemerges in the form of a water jet

13

What do subduction zones and spreading centers have in common?

They occur where tectonic plates move apart or come together

14

What are the features of continental shelves?

- widths average 65 km
- have scars from glaciers and rivers from when the sea level was different
- covered with silt, sand, and mud sediments

15

What is a continental shelf break?

A point where the depth of the slope rapidly increases

16

What are turbidity currents?

- Currents caused by earthquakes of overloading sediments on steep slopes
- fast moving avalanches of mud, sand, and water

17

What are submarine canyons? How are they formed?

- contains on continental shelf
- formed by past rivers and glaciers
- formed by turbidity currents

18

What are oceanic ridges? How are they formed?

- submarine mountain ranges
- formed by divergent boundaries separating and releasing magma

19

What is an abyssal plain? How is it formed?

- a vast flat plain at the bottom of the ocean
- formed by falling sediments from surface or turbidity currents

20

What are seamounts?

- Steep-sided volcanoes rising abruptly
- sometimes become islands

21

What are guyots?

Seamounts with flat tops

22

How do seamounts and guyots form?

Rapid undersea buildup of basalt and volcanism

23

What is a fracture zone at a transform fault?

A long narrow mountainous submarine lineation that separates ocean floor ridges. This is formed by tectonic plates sliding past each other.