Investigation of multi-scale crustal magnetic fields and their implications for the evolution of Martian dynamo

Mars presently has no significant global-scale or dipole-like magnetic field from a source in the deep interior, e.g., a Martian dynamo. However, a strong remnant magnetic field was unambiguously detected above the ancient Martian crust in the southern highlands which indicating an active dynamo in past. Magnetic fields detected by orbiting satellites provided abundant crustal remnant magnetization information with a usual scale larger than ~100 km as magnetic field signals with a smaller wavelength attenuate significantly with increasing altitude. Measurements from the Martian surface (e.g., Zhurong rover and InSight lander) can provide remanent magnetic field information at smaller scales, such as the hundred meter scale. Here in this study, we investigate the crustal magnetic fields at different scales from both satellites and surface observations. The findings cover the potential formation mechanisms of large-scale magnetic stripes on Mars, the magnetic signatures of intermediate- and small-scale impact craters, and the processes of surface small-scale magnetic anomalies. The research outcomes offer supports for advancing our understanding of the evolution of the Martian magnetic fields and its habitability.