Oceanography Week Four
1. Why do we have so many features on the seafloor?: Tectonic plates, spreading centers,
and recycling movement of earth.
2. Why are spreading center mountains (mid ocean ridges) so rugged ?: Cooled lava,
erosion.
3. What feature accounts for most of the area in the oceans?: Continental slope regions.
4. What is a continental shelf?: The continental shelf is an underwater landmass which extends from a
continent.
5. Sketch a profile from Boston to the Mid-Atlantic Ridge (label all the features)-
: (notes)
6. If you drilled in to the center of an atoll what would you find and the surface
and at depth?: Surface: coral reef
Depth: seamount
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, 7. Geologically, what are three ways to change sea level.: 1. more mountains = lower sea
level
2. more spreading = higher sea level
3. more ice = lower sea level
8. How is it that sand can be found in the deep ocean environment.: Turbidity currents.
9. How do we know about the ocean bottom?: Bathymetry, mapping of ocean floor.
10. Why is a continental shelf considered an extension of the adjacent conti-
nent?: The continental shelf is much more like the continent than the deep ocean floor with hills, depressions,
sedimentary rocks, and mineral and oil deposits similar to those on nearby dry land.
11. How is an active tectonic margin different from a passive tectonic margin?: -
Active margin: tectonically active, narrow
Passive margin: tectonically quiet, wide
12. How do submarine canyons form - two ways?: Turbidity currents, earthquakes.
13. How has sea level varied with geologic time? Is sea level unusually high or
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1. Why do we have so many features on the seafloor?: Tectonic plates, spreading centers,
and recycling movement of earth.
2. Why are spreading center mountains (mid ocean ridges) so rugged ?: Cooled lava,
erosion.
3. What feature accounts for most of the area in the oceans?: Continental slope regions.
4. What is a continental shelf?: The continental shelf is an underwater landmass which extends from a
continent.
5. Sketch a profile from Boston to the Mid-Atlantic Ridge (label all the features)-
: (notes)
6. If you drilled in to the center of an atoll what would you find and the surface
and at depth?: Surface: coral reef
Depth: seamount
1/2
, 7. Geologically, what are three ways to change sea level.: 1. more mountains = lower sea
level
2. more spreading = higher sea level
3. more ice = lower sea level
8. How is it that sand can be found in the deep ocean environment.: Turbidity currents.
9. How do we know about the ocean bottom?: Bathymetry, mapping of ocean floor.
10. Why is a continental shelf considered an extension of the adjacent conti-
nent?: The continental shelf is much more like the continent than the deep ocean floor with hills, depressions,
sedimentary rocks, and mineral and oil deposits similar to those on nearby dry land.
11. How is an active tectonic margin different from a passive tectonic margin?: -
Active margin: tectonically active, narrow
Passive margin: tectonically quiet, wide
12. How do submarine canyons form - two ways?: Turbidity currents, earthquakes.
13. How has sea level varied with geologic time? Is sea level unusually high or
2/2
