Global Major-Element Maps of Mercury from Four Years of MESSENGER X-Ray Spectrometer Observations
Larry R. Nittler, Elizabeth A. Frank, Shoshana Z. Weider, Ellen Crapster-Pregont, Audrey Vorburger, Richard D. Starr, Sean C. Solomon
(Submitted on 2 Mar 2020)
The X-Ray Spectrometer (XRS) on the MESSENGER spacecraft provided measurements of major-element ratios across Mercury’s surface. We present global maps of Mg/Si, Al/Si, S/Si, Ca/Si, and Fe/Si derived from XRS data collected throughout MESSENGER’s orbital mission. We describe the procedures we used to select and filter data and to combine them to make the final maps, which are archived in NASA’s Planetary Data System. Areal coverage is variable for the different element-ratio maps, with 100% coverage for Mg/Si and Al/Si, but only 18% coverage for Fe/Si north of 30 ? N, where the spatial resolution is highest. The spatial resolution is improved over previous maps by 10-15% because of the inclusion of higher-resolution data from late in the mission when the spacecraft periapsis altitude was low. Unlike typical planetary data maps, however, the spatial resolution of the XRS maps can vary from pixel to pixel, and thus care must be taken in interpreting small-scale features. We provide several examples of how the XRS maps can be used to investigate elemental variations in the context of geological features on Mercury, which range in size from single ?100-km-diameter craters to large impact basins. We expect that these maps will provide the basis for and/or contribute to studies of Mercury’s origin and geological history for many years to come.
Comments: Accepted for publication by Icarus. 38 pages, 10 figures in main text, plus 6 supplemental figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
DOI: 10.1016/j.icarus.2020.113716
Cite as: arXiv:2003.00650 [astro-ph.EP] (or arXiv:2003.00650v1 [astro-ph.EP] for this version)
Submission history
From: Larry Nittler
[v1] Mon, 2 Mar 2020 04:24:53 UTC (2,590 KB)
