The symmetrical pattern of magnetic polarities about spreading ridges in oceanic crust basalts indicates that:
A)each plate has had an independent set of magnetic reversals.
B)basalt retains its magnetic signature for only a few million years.
C)new ocean crust is created by volcanism at oceanic ridges and old crust moves laterally away from the ridge.
D)the oceanic crust is geologically young.
E)magnetic polarity reverses but northern and southern hemispheres do not.

Question

Quizplus · Accepted Answer

The symmetrical pattern of magnetic polarities about spreading ridges in oceanic crust basalts indicates that new ocean crust is created by volcanism at oceanic ridges and old crust moves laterally away from the ridge. The alternating magnetic polarities on either side of the ridge correspond to periods of normal and reversed magnetic field directions, which are recorded in the solidifying basalt as it moves away from the ridge. This process, known as seafloor spreading, is responsible for the creation of new oceanic crust and the lateral movement of tectonic plates.

The Symmetrical Pattern of Magnetic Polarities About Spreading Ridges in Oceanic