Rift valleys with mafic volcanics are ________ margins.
A)extensional
B)continent-continent
C)continent-ocean
D)ocean-ocean

Question

Quizplus · Accepted Answer

Rift valleys are formed due to extensional forces where the lithosphere is being pulled apart. Mafic volcanics are common in these areas due to the presence of mantle material, and the volcanic activity is a result of melting that occurs as the lithosphere thins and stretches. This type of margin is not associated with convergent plate boundaries (continent-continent, continent-ocean, or ocean-ocean) where volcanism is typically felsic in composition.

Rift Valleys with Mafic Volcanics Are ________ Margins