Earlier we discussed the concept of isostasy, where lower density rocks rise higher than higher density rocks. How is the variation of water depth at spreading centers (ridges) controlled by isostasy?
A) The lithosphere cools as it moves away from the ridge axis by sea floor spreading, and cooler rocks are lower density, so the sea floor gets deeper as the lithosphere gets more dense.
B) Volcanic rocks are lighter than other rocks, and so the abundant volcanic rocks at the ridges are lower density features that produce the seafloor topography.
C) It has nothing to do with isostasy; the areas are simply high because there are chains of active volcanos along the ridge crest, producing the topography.
D) Oceanic ridges are sites where the lithosphere is carried into the mantle on one side (aka subduction zones), and the volcanos along these margins produce the ridge by buildup of lower density crust.
A
You might also like to view...
A storm surge results from the high air pressure associated with major storms.
Answer the following statement true (T) or false (F)
The planet ________ is characterized by a strong greenhouse effect
Fill in the blank(s) with the appropriate word(s).
Flat, stable areas of continental crust tend to be located ________
A) in areas that receive large amounts of rainfall B) along coastlines C) in the interior of continents D) near desert regions
Fact: The Arctic latitudes are warming, which has released methane (a greenhouse gas) from thawing Arctic permafrost. This has increased the rate of warming in the Arctic. Systems analysis would label this as ________
A) an open system B) a closed system C) a negative feedback loop D) a positive feedback loop E) an equilibrium condition