QUOTE (serpens @ Dec 2 2018, 04:45 PM)
Assuming that early Mars reflected Earth with a molten core dynamo, albeit smaller, then the magnetic stripes of alternating polarity seem to indicate reversals of the magnetic field combined with either plate tectonics, true polar wander or perhaps a combination of both. The dynamo shut down in the first billion years, possibly due to cooling and the residual, induced fields have been disrupted due to both large impact events and heating due to volcanic activity. It is a pity that we cannot measure the depth of the residual crustal magnetic field as this, combined with the results of Insights thermal determinations could allow us to pin down when the dynamo shut down.
I remember photocopying the Icarus paper you mention in 2000. Its a neat idea but it was also a very early guess after the 1999 MGS-MAG data came out.
Look at the relationship between the impact basins and the surviving magnetic region. It's all you need. Continental drift is unnecessary in this case.
Some ground truth in this matter would make a huge difference.