Download The Ocean Floor - Mr. Haan`s Science

THE OCEAN FLOOR
CHAPTER 14 PG 393
A. THE VAST WORLD OCEAN
1. The blue planet
a. 71% of earth is covered by ocean
b. Oceanography – study of the ocean
2. Geography of oceans
a. 4 main ocean basins
1) Pacific Ocean
a) Largest ocean
b) Deepest ocean (average depth 2.45 miles)
2) Atlantic
a) Half the size as Pacific and not as deep
b) East coast of USA
3) Indian Ocean
a) Smaller than Atlantic
b) Same average depth as Atlantic
c) Sothern hemisphere
4) Arctic Ocean
a) 7% the size of Pacific
b) 25% as deep as other oceans
b. 5th ocean
1) Southern/Antarctic ocean
2) Historically not included
c. 1 global ocean
3. Mapping the Ocean Floor
a. Topography – detailed mapping of areas features
b. Will find – mountain ranges, trenches, plateaus, and
volcanoes
c. HMS Challenger – lowered long weighted cables
d. Today
1) SONAR
a) Sound Navigation
And Ranging
b) Bounces sound
waves off ocean floor
c) Records time it
takes to return
• Multiple beam sonar –
more than one sound
source
2) Satellites
3) Submersibles
a) Small underwater craft used for deep sea research
b) Varying technology: cameras, thermometers, pressure
gauges, mechanical arms, etc.
c) Can be manned or unmanned
B. OCEAN FLOOR FEATURES
1. Continental Margins
a. Transition zone b/w continents and the adjacent ocean floor
b. Continental Shelf
1) Gentle sloping surface extending from the shoreline
2) Contain important features
a) Mineral deposits
b) Oil and natural gas
c) Sand and gravel deposits
c. Continental Slope
1) Marks the boundary b/w continental and oceanic crust
2) Submarine canyons
a) Deep, steep-sided valleys
b) Made by turbidity currents – movements of dense,
sediment-rich water down the continental slope
d. Continental Rise – continental slope merges into a more
gradual incline
2. Ocean basin floor
a. Area between continental margin and mid-ocean ridge
b. Deep-Ocean Trenches
1) Long, narrow creases in ocean floor
2) Cause deepest parts of ocean
3) Mariana Trench
a) Deepest known place on earth
b) 11,022 meters (6.8 miles)
4) Occur at subduction zones
5) Have earthquakes and volcanoes
MARIANA TRENCH
Deepest Place In The World
ANIMALS OF THE MARIANA TRENCH
c. Abyssal plains
1) Deep and extremely flat
features
2) Sediments burry all other
features by turbidity currents
d. Seamounts – submerged volcanic
peaks
3. Mid-ocean ridges
a. Near center of most ocean basins
b. Longest topographical feature on earth
c. Seafloor spreading
1) Happens at divergent plate boundaries
2) Forms new ocean floor with rising magma
d. Hydrothermal vents
1) Causes mineral-rich, heated water
2) Hits cold water and S, Fe, Cu, and Zn precipitate out
HYDROTHERMAL VENTS
TUBE WORMS
C. SEAFLOOR SEDIMENTS
1. Terrigenous – sediments originating from land
2. Biogenous – sediments with a biological origin
a. Calcareous ooze – produced from calcium carbonate in
shells
b. Siliceous ooze – produced from diatoms
3.
Hydrogenous – minerals that crystallize directly from ocean
water by chemical reactions
D. RESOURCES FROM THE SEAFLOOR
1. Energy Resources
a. Oil and natural gas
1) Main energy source from ocean floor
2) Remains of animal remains
3) Concerns with oil spills
2010 BP OIL SPILL
b. Gas Hydrates
1) Compact chemical structures
2) Typically form when bacteria break down organic
material
2. Other Resources
a. Sand and Gravel
1) 2nd in economic value to petroleum industry
2) Used for landfills and concrete
3) Some places contain titanium, gold, or diamond
deposits
b. Manganese Nodules
1) Lumps of manganese and other metals
2) Fairly wide spread
3) Environmental concerns with mining
c. Evaporative salts
1) Salt precipitates out of water
2) Gives halite (table salt)
3) Used for seasoning, preserving, agriculture, and clothing
industry