Global Spectral Properties and Lithology of Mercury: The Example of the Shakespeare (H‐03) Quadrangle

Abstract

The MErcury Surface, Space ENvironment, GEochemistry and Ranging mission showed the surface of Mercury with an accuracy never reached before. The morphological and spectral analyses performed thanks to the data collected between 2008 and 2015 revealed that the Mercurian surface differs from the surface of the Moon, although they look visually very similar. The surface of Mercury is characterized by a high morphological and spectral variability, suggesting that its stratigraphy is also heterogeneous. Here, we focused on the Shakespeare (H‐03) quadrangle, which is located in the northern hemisphere of Mercury. We produced an 8‐color cube of this quadrangle at 450‐m per pixel spatial resolution and with a complete coverage. Various selected color maps based on this eight‐color cube were used to analyze the spectral properties of this region to define its compositional variability and identify some clear units constrained by relevant spectral parameters: for example, we identified a higher concentration of low reflectance material around three main craters of Shakespeare (Degas, Akutagawa, and Sholem Aleichem) and in the area to the south of Sobkou Planitia delimited by 24.4°N to 28.4°N and −140°W to −125°W. Moreover, we selected some regions of interest, which can be proposed as particularly interesting targets for the Visual and Infrared Hyper‐spectral Imager and Mercury Radiometer and Thermal Imaging Spectrometer instruments onboard the BepiColombo spacecraft. This work can help for the geological analysis of this quadrangle, by integrating information that are usually not derived with a single morphostratigraphic analysis.

Near‐Ultraviolet to Near‐Infrared Spectral Properties of Hollows on Mercury: Implications for Origin and Formation Process

“…Moreover, we compared MDIS measurements with MASCS spectra directly. We used the experiment data record of MDIS-WAC (Hawkins et al, 2007), and applied a radiometric and photometric calibration (Bott et al, 2019;Domingue et al, 2015;Hapke, 1981). Average reflectance obtained in both areas (the original area studied by Vilas et al [2016] and the area observed with MASCS) of the hollows is represented in Figure 10.…”

Spectral Units Analysis of Quadrangle H05‐Hokusai on Mercury

“…Starting from this mosaic, we produced color-composite maps to investigate variations associated with spectral variabilities. For a more in-depth analysis, we defined new spectral parameters, in addition to indices already known from the literature, such as spectral ratios and principal component analysis (see Blewett et al, 1997Blewett et al, , 2007Bott et al, 2019;Denevi et al, 2009). Starting from reflectance and these new indices, we finally define SUs.…”

Rationale for BepiColombo Studies of Mercury’s Surface and Composition

“…Enhanced MESSENGER colour image (as Fig. 1) of the Shakespeare quadrangle, H03 (Bott et al 2019). This colour combination emphasises spectral units, such as the 'low reflectance material' (LRM) characterized by low reflectance and low spectral slope (dark blue in this rendering), and faculae (F), thought to be pyroclastic deposits, characterized by high reflectance and high spectral slope (orange in this rendering)…”

“…Planmap and allied efforts are also devoted to integrating morphological and spectral information by redefining geological units, through consideration of colour variation on spectral index maps as well as morphostratigraphic characteristics (e.g., Bott et al 2019;. For example, the spectrally-defined 'low reflectance material' makes up some, but by no means all, of the morphostratigraphically-defined intercrater plains (Fig.…”