Two geophysicists are debating the mechanisms driving plate tectonics. Geophysicist Alpha proposes that mantle convection, driven by heat from Earth's core, is the primary force, with cooler, denser material sinking and pulling plates along. Geophysicist Beta argues that slab pull, where the weight of subducting oceanic lithosphere at trenches pulls the rest of the plate, is the dominant driver.
Which observation would provide the most compelling evidence in favor of Geophysicist Beta's hypothesis?
Correct: B
Geophysicist Beta's hypothesis centers on 'slab pull,' the weight of subducting oceanic lithosphere. Detailed seismic imaging showing large, deep slabs of oceanic crust descending into the mantle (Choice B) would provide direct visual evidence of this process occurring and demonstrating the significant mass and depth of these subducting slabs, thus strongly supporting the idea that their weight is a primary driver. Choice A supports Alpha. Choice C undermines mantle convection (Alpha). Choice D supports mantle plumes (Alpha).