How do magnetic stripes of iron in ocean rock provide evidence of seafloor spreading? They show when Earth's poles reversed. They show how the density of the seafloor has changed. They reveal a matching pattern on either side of the ridge. They reveal differences in the mineral composition of newly created rock. Which statement describes the cyclic nature of seafloor spreading? Continents are created. New oceanic crust is created. Volcanoes erupt and remove crust. Old crust gets thicker at subduction zones.