Download Oceanography Review Key

Name ____________________________
Oceanography
1. Define the following features of waves:
a. Wave length: horizontal distance from crest to crest or trough to trough
b. Wave height: vertical distance between crest and trough
c. Wave period: time it takes one wavelength to pass a given point
d. Refraction: bending of waves as they approach shore
e. Wave speed: wavelength/period
2. Which is the deepest ocean? Pacific Ocean
3. Where are the deepest ocean trenches found? Pacific Ocean
4. Explain how you determine ocean depth using echo sounding techniques.
Send a sound signal through the water to the ocean floor. Measure the length of
time it takes the signal to get to the bottom and echo back. Multiply this by the
speed of sound and divide by 2.
5. If the speed of sound is approximately 1500 m/s and it takes 4 seconds for a sound
wave to reach ocean bottom and come back, how deep is the ocean at this point?
3,000 m
6. List the features found at active continental margins. Continental shelf, continental
slope, trench
7. List the features found at passive continental margins. Continental shelf,
continental slope, continental rise.
8.
The mid-ocean ridges make up the longest mountain range on Earth. Some pieces
of the ridge are offset. Why? There are transform faults along the mid-ocean
ridges.
9. The flattest feature of the ocean floor is the abyssal plains which are covered by
sediments. What is the source of this material? Sediments from continental rivers.
10. What features of the ocean floor are related to plate tectonics?
Mid-ocean ridges: site of new oceanic crust formation
Trenches: site of old oceanic crust destruction
11. Describe the sources of ocean sediments.
Terrigenous – from continental rocks and minerals
Biogenous – from former marine life
Hydrogenous – from chemical reactions
12. Why won’t you find calcareous ooze at the bottom of the Marianas trench?
It dissolves at depth prior to getting to the bottom of the trench