抄録
Natural remanent magnetization (NRM) of chondrite has been expected to help researchers to elucidate the nature of the magnetic field in the primordial solar system. In the case of Allende carbonaceous chondrite, the NRM is stable, with a uniform direction resulting from the presence of pentlandite, while the presence of magnetite and FeNi grains does not affect NRM carriers. Probably the magnetic field was present when the pentlandite was formed by dehydration of the Allende parent body. At that time, the molten core of FeNi might have conducted the magnetic field with dynamo. Ordinary chondrite usually shows inhomogeneous NRM intensity and scattered direction. Shock experiments revealed that the NRM is remagnetized by shock. Probably the NRM of low-shock impedance meteorites consisting of meteorites such as iron, stony iron, and ordinary chondrite could have been remagnetized by shocks with a pressure >0.1GPa when the parent body collided with asteroids. Only carbonaceous chondrite may have carried a significant NRM in the protoplanets, because of their high shock impedance.
