There are two possible explanations for how this could have occurred. Explanation 1 is that the poles moved around and the continent stayed in the same place. When the most recent lava formed, this green stuff, the pole was right up here, where it is today.But back when this volcano was making the yellow lava, the pole was in a slightly different place. The oldest lava flow is recording a pole that was more like in that direction.There were two possible explanations for this: Before plate tectonics was accepted, most geologists thought that the pole must have moved.

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A geologist armed with a magnetometer could sample down through the layers of solidified lava and thus track the direction and intensity of the field over the span of geologic time recorded by that volcano.

In fact, geologists did do this, and they discovered that the direction of the north pole was not stationary over time, but instead had apparently moved around quite a bit.

The study of the Earth's magnetic field as recorded in the rock record was an important key in reconstructing the history of plate motions.

We have already seen how the recording of magnetic reversals led to the confirmation of the seafloor spreading hypothesis.

Let’s say that the red one points sort of in this direction and the yellowish one looks like this.

The green one was formed during the field like it is today so its north is like that.

In the upper series of sketches there is a landmass on a planet with a dipole field.

A volcano on that land mass erupts at various intervals, creating layers of igneous rock which are permanently magnetized with different orientations.

The pole could not be in two places at once, and furthermore the ocean floors all recorded either north or south, but not directions in between.