Paleomagnetism of the Rochechouart meteorite impact crater: Field reversal or self reversal?

Paleomagnetic investigations on the Rochechouart (France) impact structure reveal three kinds of stable magnetization directions: solely normal, solely reversed and samples with multiple, often antipodal, magnetization components. Possible explanations for this observation are: (1) the rocks record a geomagnetic field reversal during the time it took the impact melts and suevites to cool through the Curie unblocking temperature or (2) a self-reversal mechanism is to blame. We will present data from detailed stepwise demagnetization, rock magnetic and Thellier-Thellier paleointensity experiments to distinguish between the two possibilities.