How strong is the memory of the geomagnetic field? A critical appraisal of reversal asymmetry in precambrian rocks of Scotland

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The Earth's magnetic field reverses its polarity such that after a reversal magnetic compasses point in the opposite geographical direction. This has occurred repeatedly throughout geological time. In general, reversals of the field are anti-parallel and the directions of magnetisation before and after a reversal lie at 180 degrees to each other. However, there are now several cases where the directions of magnetisation recorded in rocks indicate that a series of reversal may not have been anti-parallel. These observations might be the products of several magnetisation events and in these circumstances the directions reflect different parts of the geological history of the sampling site and not unusual behaviour of the field. This project is designed to test if ancient magnetisations have recorded such unusual behaviour. As with many other natural systems atypical behaviour (e.g. illness) can be as informative as the normal state. Thus, these results may lead to a greater understanding of how the Earth's field behaves and has evolved.