Do meteorite impacts the geomagnetic field and can meteorites retain the record of planetary magnetic fields?

陨石撞击深刻地影响了我们太阳系行星的演化。撞击事件所涉及的动能以冲击波的形式释放，瞬间压力有时超过100 GPa，分布在数百平方公里的范围内。由冲击产生的地震波在到达地球核心时可能会影响地球发电机。火星发电机的停止也可能是由一颗大陨石撞击造成的。我们建议对几个陆地撞击坑进行详细、系统的古地磁研究，以测试地磁场是否受到撞击的扰动。如果撞击事件强烈地影响了地球发电机，那么这些影响在古地磁数据中应该是明显的，无论是磁场方向的摆动还是强度的波动。我们打算跟踪这些变化的冷却记录的岩石被熔化的影响。我们还将对受到冲击的岩石进行研究，以确定它们的岩石磁性如何被冲击过程修改和叠加。此外，我们将进行陨石的古地磁研究，以限制月球，火星和微行星早期磁场的强度。陨石和撞击坑的古地磁是有联系的，因为前者的一个关键的场源是撞击产生的等离子体。鉴于几乎所有的陨石样品在从其母体喷出时都受到了冲击，因此了解冲击波对岩石磁性的影响至关重要。

Meteorite impacts have profoundly influenced the evolution of planets in our solar system. The kinetic energy involved in impact events is released as a shock wave, with instantaneous pressures sometimes >100 GPa spread over hundreds of square kilometers. Seismic waves generated by the shock can potentially influence the geodynamo when reaching the Earth s core. Cessation of the Martian dynamo may have also been caused by a large meteorite impact. We propose to carry out detailed, systematic paleomagnetic studies of several terrestrial impact craters to test whether the geomagnetic field was perturbed by the impacts. If impact events strongly influenced the geodynamo, then the effects should be evident in the paleomagnetic data, either as swings in magnetic field direction or as fluctuations in intensity. We intend to track these changes in the cooling record of the rocks that were melted by the impact. We also will conduct studies on rocks shocked by the impacts in order to determine how their rock magnetic properties were modified and overprinted by the impact process. Moreover, we will conduct paleomagnetic studies of meteorites to constrain the intensities of early magnetic fields of the Moon, Mars, and planetesimals. The paleomagnetism of meteorites and impact craters are linked in that one of the key proposed field sources of the former is impact-generated plasmas on the parent body. It is critical to develop an understanding of the effects of shock waves on rock magnetic properties given that nearly all meteorite samples were shocked during ejectionfrom their parent bodies.