Which is denser: a 100-million-year-old oceanic lithosphere near a convergent boundary, a 15-million-year-old oceanic lithosphere near a rift, or the upper part of the asthenosphere?

Question

Quizplus · Accepted Answer

As oceanic lithosphere ages, it cools and becomes denser. Therefore, the 100-million-year-old oceanic lithosphere near a convergent boundary is denser than a 15-million-year-old oceanic lithosphere near a rift. The upper part of the asthenosphere is less dense than either of these lithospheres due to its partially molten state.

Which Is Denser: a 100-Million-Year-Old Oceanic Lithosphere near a Convergent