Flashcards in Exam 2.2 Deck (23):
What is bathymetry
The measurement of depth of water in oceans, seas, or lakes
What tools are used in bathymetry?
- remotely operated vehicles
What are the 3 parts of the continental margin?
- continental shelf
- continental slope
- continental rise
What is an ocean basin?
- an area of ocean floor between continental margins
What is a continental margin?
The shallow water found in proximity to the continent
What is the difference between continental shelf at active margins and at passive margins?
Passive margins: broad continental shelves
Active margins: narrow shelves
What are the passive margin characteristics?
- no earthquakes or volcanoes
- plate moves away from mid atlantic ridge
- gentle slopes, no trenches
- wide shelves
What are the active margin characteristics?
- narrow shelves
What is a continental slope?
- extend from shelf to rise
- ranges from 1 km to 10 km
How do continental rises form?
Sediment builds up from
- turbidity currents
- underwater landslides
What are hydrothermal vents?
An opening in the sea floor out of which heated mineral water flows
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
What do subduction zones and spreading centers have in common?
They occur where tectonic plates move apart or come together
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
What is a continental shelf break?
A point where the depth of the slope rapidly increases
What are turbidity currents?
- Currents caused by earthquakes of overloading sediments on steep slopes
- fast moving avalanches of mud, sand, and water
What are submarine canyons? How are they formed?
- contains on continental shelf
- formed by past rivers and glaciers
- formed by turbidity currents
What are oceanic ridges? How are they formed?
- submarine mountain ranges
- formed by divergent boundaries separating and releasing magma
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
What are seamounts?
- Steep-sided volcanoes rising abruptly
- sometimes become islands
What are guyots?
Seamounts with flat tops
How do seamounts and guyots form?
Rapid undersea buildup of basalt and volcanism