Notice the part of this image labeled "continued trench rollback." What is happening in "trench rollback"?
A)Old, dense lithosphere sinks, creating slab suction that pulls the upper plate toward the trench.
B)Continued tension on the plate results in rifting, dropping blocks of continental crust.
C)The trench gets deeper as the descending plate locks against the overriding plate and pulls it down.
D)Rising magma plutons melt the base of the lithosphere to create a depression.

Question

Notice the part of this image labeled "continued trench rollback." What is happening in "trench rollback"?
A)Old, dense lithosphere sinks, creating slab suction that pulls the upper plate toward the trench. 
B)Continued tension on the plate results in rifting, dropping blocks of continental crust. 
C)The trench gets deeper as the descending plate locks against the overriding plate and pulls it down. 
D)Rising magma plutons melt the base of the lithosphere to create a depression.

Quizplus · Accepted Answer

"Trench rollback" refers to the process where an old, dense lithosphere sinks into the mantle at a subduction zone, creating slab suction that pulls the upper plate (or overriding plate) towards the trench. This causes the trench to migrate backwards (or rollback) over time. Choice A correctly describes this process. Choices B, C, and D describe different geological processes that are not related to trench rollback.

Notice the Part of This Image Labeled "Continued Trench Rollback