The combined cause of step-like slopes and black soil in the Deccan Trap is linked with what?

Correct answer: Basaltic lava flows

The correct answer is basaltic lava flows. The Deccan Trap was built by extensive outpourings of fluid basaltic lava, especially during the Cretaceous period. As successive lava sheets cooled and solidified, they produced layered, step-like relief; the word “trap” is associated with a stair-step appearance. Weathering of the basalt, together with the accumulation of clay-rich material, helped form the black cotton soil that is widespread over parts of the Deccan Plateau. Himalayan glaciers, marine coral, and Ganga alluvium do not explain both features. Glaciers are associated with high mountains, coral forms reef structures, and alluvium is river-deposited sediment. Thus basaltic lava flows provide the unified explanation.