Marine magnetic anomaly belts are widest when and where ____________.
A) continents are joined to form supercontinents
B) sea-floor spreading rates are relatively rapid
C) sea-floor spreading rates are relatively slow

Question

Quizplus · Accepted Answer

Marine magnetic anomaly belts are created by the alternating bands of magnetic polarity on the ocean floor, which are generated by sea-floor spreading. When sea-floor spreading rates are relatively rapid, these bands of magnetic polarity accumulate at a faster rate, causing the anomaly belts to widen. When sea-floor spreading rates are slower, the bands accumulate at a slower rate, causing the anomaly belts to be narrower. Therefore, the widest marine magnetic anomaly belts occur during periods of rapid sea-floor spreading. While continents joining together to form supercontinents can cause changes in sea-floor spreading rates, this is not always the case, and it does not explain the consistent relationship between spreading rates and the width of the anomaly belts.

Marine Magnetic Anomaly Belts Are Widest When and Where ____________