Volcanology targets for BepiColombo at Mercury

Abstract:

Post-MESSENGER questions about Mercury’s surface and composition that BepiColombo should be able to answer are described in [1]. Here we highlight aspects of the planet’s volcanology amenable to resolution by BepiColombo.

Smooth plains and most intercrater plains were emplaced as large volume lava flows. Regolith formation has obscured many details, but we might hope to see flow fronts and (if they exist) collapsed lava tubes in higher resolution images. Relationships between adjacent smooth plains units are problematic; spatially-resolved elemental and mineralogic mapping by BepiColombo should help to differentiate their magmatic provenance [2], and higher resolution imaging may clarify the apparent continuity between plains units interior and exterior to the Caloris basin [3] and a few other examples. Similar clarity should emerge concerning enigmatic smooth ponded patches [4], and on whether candidate volcanic cones [5] are real or “face on Mars” illusions.

Better imaging and topographic mapping of the interiors of explosive volcanic vents should clarify cross-cutting and other age relationships in the substantial fraction that are compound vents [6,7], and how they relate to faults. Elemental and mineralogic mapping of the surrounding faculae [8,9] should cast light on the volatile phase responsible for driving the explosive eruptions, and may find exceptions to the apparent rule that explosive volcanism is never older than local effusive volcanism. Comparison with ‘red pitted ground’ [10] should equally progress our understanding.

Acknowledgement: this work is supported by the EU Horizon 2020 research and innovation programme under grant agreement No. 776276, PLANMAP. Man, Malliband and Pegg PhD’s were financed by the UK’s STFC and the Open University Space SRA.

[1] Rothery, D A, et al. Space Sci Rev 216 (2020): 66. [2] Namur, Olivier, et al. EPSL 439 (2016): 117-128. [3] Rothery, David A., et al. JGR Planets 122.3 (2017): 560-576. [4] Malliband, C., et al. LPSC 2047 (2018): 6092. [5] Wright, J., et al. JGR Planets 123.4 (2018): 952-971. [6] Rothery, D. A. et al., EPSL 385 (2014): 59-67. [7] Pegg, D. L. et al., LPSC 2132 (2019): 1273 [8] Weider, S. Z., et al. GRL 43.8 (2016): 3653-3661. [9] Besse, S., et al. JGR Planets 125.5 (2020) [10] Thomas, R. J., et al JGR Planets 119.10 (2014): 2239-2254.