Study Guide - Seafloor
1. The topography of the ocean floor actually consists of
A. sediments only a few meters thick.
B. oceanic ridges and oceanic trenches.
C. thousands of submarine volcanoes dotting vast featureless plains.
D. ridges, trenches, hills, vast plains, plateaus, and volcanoes.
E. vast submarine chasms deeper, wider and longer than the Grand Canyon.
2. What are the components of the continental margin, from sea level toward the ocean basin?
3. What are turbidity currents?
4. Match the descriptions with the appropriate regions of continental margins:
_____ its deeper edge lies at an average
A. Continental shelf
of 135 m
B. Continental slope
_____ it is cut by many deep, steep-sided
C. Continetal rise
canyons
_____ it slopes seaward at 2ø to 4ø on
averages, sometimes as much as 25ø
_____ changes in sea level drown and
expose this portion
_____ contains glacial sediments, fossil
mammoths, trees and archeological
remains
_____ sedimentation here is affected by
waves and tides
_____ sediments here are largely deposited
by turbidity currents
5. What are three of the characteristics of an active continental margin?
6. What is an example of an active margin, in the Western hemisphere?
7. Match the appropriate topographic-geologic feature of the sea floor with the geographic region cited.
_____ East coast of South America
A. Abyssal Plains
_____ region between the North Atlantic
B. Passive margin
spreading ridge and the continental
C. Active margin
shelf of the United States
D. Oceanic Trenches
_____ offshore of the continental shelf of
E. Spreading Ridges
western South America
_____ the regions offshore, and east of,
Japan and the Philippine Islands
_____ the region offshore, south of the
Aleutian Islands
_____ the region offshore of, and
surrounding Great Britain
_____ the region south, and offshore of,
Sumatra and Java
_____ the feature containing the deepest
site in all the oceans
_____ the region off the coast of southern
California
_____ the region off the east coast of
Argentina
_____ the mountain chain which includes
the island of Iceland
8. What are some of the characteristics of oceanic ridges?
9. Of what rock type are oceanic ridges composed?
10. What causes submarine hydrothermal vents?
11. What is the difference between a fringing reef and a barrier reef?
12. What is an ophiolite?