Igneous processes and dike swarms: Magnetic signatures in the Solar System

Abstract:

Large igneous provinces (LIP) are common in planetary environments: at Mars, Venus, Mercury, Io, and of course the Earth and its Moon. Dike swarms are often associated with LIPs, and are one of the only remaining signatures of a LIP in old, eroded settings. On Earth, dike swarms are often recognized by their magnetic signatures. The World Digital Magnetic Anomaly Map (version 2, 2015) is now based on a higher resolution 5 km grid, so many more dike swarms are apparent. We review this latest compilation. Several new high resolution planetary magnetic data sets have also recently become available, and we review evidence for igneous processes, and dikes, in these new data sets. We also review the prospect for new planetary magnetic data sets that might further elucidate igneous processes. At Mars, for example, we have photogeologic evidence for a host of dike swarms, but because of the high altitude of the magnetic data sets, no magnetic evidence exists. A new technique based on remotely sensing the magnetic field of the atomic Na in micro-meteorite ablation layers offers the promise of improving the spatial resolution by a factor of 2-4 at Mars.