Download Features of the Ocean Basins

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Supercontinent wikipedia, lookup

Plate tectonics wikipedia, lookup

Oceanic trench wikipedia, lookup

Cimmeria (continent) wikipedia, lookup

Pangaea wikipedia, lookup

Abyssal plain wikipedia, lookup

Transcript
The Ocean Basins
Physical Oceanography
Features of the Ocean Basins
• Continental margin: portion of
ocean made up of continental crust
Features of the Ocean Basins
• continental shelf:
flat part of continental
margin covered by shallow ocean water
Formed by changes in sea level
Avg depth = 60 m
Shelf
• Relatively shallow
• 0 – 200 m
• Relatively flat with
a gradient of 2 m
drop per kilometre
Features of the Ocean Basins
• continental slope:
boundary between
continental crust and oceanic crust - The average
angle displayed by the slope is about 5 degrees.
Features of the Ocean Basins
• submarine canyons: deep, v-shaped
valley that cuts through shelf & slope
Features of the Ocean Basins
• continental rise: wedge of sediments
that separates slope from ocean floor
Features of the Ocean Basins
• abyssal plain (floor): very flat areas at
depths of 3-5 km
Features of the Ocean Basins
• mid-ocean ridge: mountain range on
ocean floor due to seafloor spreading
Features of the Ocean Basins
• trench: deep narrow valleys along the edges of subduction
zones in the ocean floor; 90% of trenches are found around the
Pacific rim.
Marianas Trench in Pacific ocean is the deepest point on
earth - 10,668 meters
Bathymetric Charts – show the contours and depths of the
seafloor topography
General Slope Features
• Sharp break from the shelf
• Angle is gentle, averaging less than 5
degrees
• Continues to a depth of 3600 m
• Often carved by deep canyons - Hudson
Canyon is famous in N.A.
Submarine Canyons
• V-shaped
• Hudson Canyon steeper than the Grand
Canyon
• Form deep sea fans from sediments
• Originated from rivers during ice ages
The
Gully!
Submarine canyon off Nova Scotia
•
• Marine protected area because of the rare corals found there
• The natural gas pipeline goes right by it…problems?
The Gully
Turbidity currents
• Turbidity currents are caused by the
slumping of sediments from the continental
slope.
• can travel at over 55 km/h
• can spread 700 km+
• Can damage underwater pipelines,
transatlantic cables
Rise
• Slope about ½ degree toward the
abyssal plain
• Sediment deposition from continent
• Range from 100 to 1000 km in width
• Only occur along passive margins,
often off the mouth of large rivers
Another look 
Features of the Ocean Basins
• seamount: underwater volcanic
mountain (some more than 1000 m high)
•
Features of the Ocean Basins
Atolls
A ring shaped island of coral reefs and coral debris.
These often form over sinking inactive volcanoes.
Features of the Ocean Basins
• coral reef: limestone structures
containing shells of animals that
surround volcanic islands
Features of the Ocean Basins
• guyot: a flat-topped submerged
seamount due to erosion
Features of the Ocean Basins
• rift valley: deep crevice in between
mountain ranges
Which coast has the wider shelf?