Question

Volcanic and other such activity at the mid-Atlantic ridge extrudes material to fill the gap between separating tectonic plates associated with continental drift. The magnetization of rocks is found to reverse in a coordinated manner with distance from the ridge. What does this imply about the Earth’s magnetic field and how could the knowledge of the spreading rate be used to give its historical record?

a) The Earth's magnetic field is constant, and the spreading rate has no impact on its historical record.

b) The Earth's magnetic field is reversing, and the spreading rate can be used to determine the timeline of these reversals.

c) The Earth's magnetic field is unrelated to tectonic activity.

d) The spreading rate affects the intensity, not the direction, of the Earth's magnetic field.

Answer 1

The magnetization of rocks at the mid-Atlantic ridge reversing in a coordinated manner implies that the Earth's magnetic field is reversing. The spreading rate of the tectonic plates can be used to determine the timeline of these reversals.

Step-by-step explanation:

The finding that the magnetization of rocks at the mid-Atlantic ridge reverses in a coordinated manner with distance from the ridge suggests that the Earth's magnetic field is reversing. The spreading rate of the tectonic plates can be used to determine the timeline of these reversals. As the tectonic plates move apart, new rocks are formed and acquire a certain magnetic orientation.

Over time, as the plates continue to spread and new rocks form, the magnetic orientation of the rocks changes. By measuring the spreading rate and the distance from the ridge, scientists can determine the timing of these magnetic reversals and create a historical record of Earth's magnetic field.