Characteristics of the Seafloor

Which is the first step in the seafloor spreading process? A crack forms in oceanic crust. Volcanoes erupt under the ocean. Molten rock rises up through the crust. Dense plates are subducted under less dense plates.

A crack forms in oceanic crust.

Which evidence originally supported Hess's idea of seafloor spreading in 1968? Younger rocks are closer to mid-ocean ridges. The destruction of crust occurs at deep-sea trenches. Oceanic rocks are pillow-shaped when formed. Rocks across the ocean floor have alternating magnetic stripes.

Younger rocks are closer to mid-ocean ridges.

Which type of material becomes molten rock at subduction zones? light plates heavy plates continental crust new oceanic crust

heavy plates

Which material rises from cracks in oceanic crust? dense crust molten rock continental crust pillow-shaped rocks

molten rock

According to the theory proposed by Harry Hess, what causes continents to move? continental drift magnetic polarity seafloor spreading deep-ocean trenches

seafloor spreading