What phenomenon of the ocean crust led scientists to propose the idea of sea-floor spreading?
A) volcanoes in Japan
B) symmetrically magnetized stripes of rock on the ocean floor
C) earthquakes in the middle of the ocean
D) mountain chains around the Pacific Ocean
E) the San Andreas fault

Question

Quizplus · Accepted Answer

Symmetrically magnetized stripes of rock on the ocean floor provided evidence of the sea-floor spreading phenomenon. As new oceanic crust is formed from volcanic activity at mid-ocean ridges, it pushes the older crust away in opposite directions. As the new crust cools, it preserves the orientation of Earth's magnetic field, creating alternating bands of normal and reversed polarity in the rocks. The symmetry of these magnetic stripes on either side of the mid-ocean ridge provided strong evidence for sea-floor spreading.

What Phenomenon of the Ocean Crust Led Scientists to Propose