Chapter 27, Problem 11TE

To determine

The way to support the theory of continental drift by seafloor’s magnetic record.

Answer to Problem 11TE

The plot of the positions of the magnetic north pole through the time revealed that over the past 500 million years, the position of the pole had apparently wandered throughout the world.

Explanation of Solution

One of the first discoveries in support of continental drift came about through the studies of Earth’s magnetic field. Many rocks have a preserved record for changes in Earth’s magnetism over time. These changes include times when the magnetic north and south poles were reversed. This magnetism from the geologic past is known as palaeomagnetism.

The two techniques that were used to support the theories of continental drift and seafloor spreading are apparent polar wander for continental drift while magnetic anomalies provided the evidence for seafloor spreading.

The magnetic variation in the consecutive bands of ocean floor parallels with mid-ocean ridges evident the theory of seafloor spreading, while apparent polar wander uses the path of Earth’s paleomagnetic poles relative to a continent that remains fixed and determines the continental drift in this manner.

Conclusion:

Therefore, the plot of the positions of the magnetic north pole through the time revealed that over the past 500 million years, the position of the pole had apparently wandered throughout the world.