Authors:

Brianna Petruccelli

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About Paper:

Unlike Earth, Mars does not have a global magnetic field, but instead exhibits localized crustal magnetic anomalies. The strongest of these anomalies are concentrated in a broad band in the southern hemisphere, corresponding to Noachian terrain that has remained largely unaltered since the earliest ~400 Myr of the planet's geologic history. These anomalies arise from remanent magnetization (a form of residual magnetism) with possible origins including early dynamo activity, but definitive mechanisms are still debated. We investigate if ancient lightning strikes could have been a dominant contributor through a process called lightning-induced remanent magnetization, which would have been feasibly facilitated by the warm, wet conditions of the Noachian period. To address this, we simulated the magnetic field strength produced by a flash of lightning by applying the Biot-Savart law to characterize its behavior. The computed field was then assimilated into a surface-wide probability distribution of lightning strikes, derived from a parameterized model of lightning frequency. Successive simulations were conducted to determine spatial convergence. The results showed that intensity is strongest in the southern hemisphere and near the planet's poles, but detectable surface signatures today are about 1,000,000× weaker and limited to the remaining exposed Noachian terrain. The next steps involve constructing a new surface- wide probability distribution of lightning strikes, derived from precipitation rates inferred from groundwater data. This distribution will then be subjected to the simulation and analysis process used previously, enabling a direct comparison to determine whether lightning-induced remanent magnetization is a plausible explanation for the observed magnetic anomalies. Keywords: Paleomagnetism; Planetary Science; Planetary Crust; Early Mars

Source:

Purdue University / 2025

Topics:

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Co-authors:

Brianna Petruccelli