Question

Every few hundred thousand years, the magnetic poles of earth reverse. Rocks that contain iron provide a record of both normal and reversed magnetic poles. The diagram below shows the pattern of normal and reversed magnetic poles as recorded in the rocks on either side of the mid-atlantic ridge. How does this show evidence of seafloor spreading?

Answer 1

The pattern of normal and reversed magnetic poles in rocks on either side of the mid-Atlantic ridge provides evidence of seafloor spreading. Scientists can determine the historical record of Earth's magnetic field by analyzing the spreading rate of the seafloor.

Step-by-step explanation:

The pattern of normal and reversed magnetic poles recorded in rocks on either side of the mid-Atlantic ridge provides evidence of seafloor spreading. As volcanic and tectonic activity occurs at the ridge, new material is extruded to fill the gap between separating tectonic plates. The magnetization of rocks is found to reverse in a coordinated manner with distance from the ridge, indicating the periodic reversal of Earth's magnetic field.

By analyzing the spreading rate of the seafloor, scientists can determine the historical record of Earth's magnetic field. As new material is added at the mid-Atlantic ridge, older rocks move away from the ridge and preserve the magnetic polarity of the time when they formed. By comparing the age of the rocks with their magnetic polarity, scientists can create a timeline of magnetic field reversals and study the history of Earth's magnetic field