Search

Abstract: Mapping tectonic features using MESSENGER data mainly acquired at high Sun incidence angle (>50°) reveals previously undetected structures. The analysis of the latter features determines an upward revision of measurements of density and spatial distribution of tectonism and thus of estimates of average contractional strain and planetary radius decrease. We calculated an average surface contraction of ∼0.23–0.30% (∼0.28% for fault dip angle θ =30°) within an area corresponding to 21% of the planet. This strain, extrapolated to the entire surface, corresponds to a decrease in radius of about 2.4–3.6km (∼3.0km for θ =30°). These values are three–four times higher with respect to previous estimates and are compatible with results from thermomechanical models. [Copyright &y& Elsevier]

In the absence of Mercurian rocks or meteorites in our collections, komatiites and boninites are often proposed as the best analogue rocks to Mercury lavas. However, despite previous work on the possible analogy between komatiites and Mercury rocks, similar work has not been done for boninites. In this work, we investigate the whole-rock geochemistry and visible/near-infrared (VNIR) spectroscopy of boninitic material collected at three specific areas of the Troodos Massif (Cyprus island). The objective is to evaluate if collected boninites, these along with other boninites present in the literature, can be analogous to Mercury geochemical terranes. On average, we find an unusually high MgO/SiO 2 ratio (0.68) for the boninites from the Troodos Massif compared with previous boninite analysis. This MgO/SiO 2 value is most closely related to the high-Mg regions of Mercury, while the average Al 2 O 3 /SiO 2 ratio (0.25) is consistent with the Mercurian intermediate terrain and to Mercury's largest pyroclastic deposit. In addition, further affinity to the high-Mg regions and the intermediate terrains of Mercury are shown in regard to Si vs. Mg, Si vs. Ca, and Si vs. Fe content for one sample in particular. We then conduct magmatic modeling on this specific sample to provide a possible parental melt composition for analogue Mercurian magmas. In conclusion, we suggest these specific locations on the Troodos Massif in Cyprus as good geochemical analogue sites for the high-Mg regions of Mercury and explain how boninites could be important benchmark samples for the chemical and spectral data expected from the BepiColombo mission. • The geochemistry and VNIR spectroscopy of boninitic material is investigated. • An high MgO/SiO 2 ratio (0.68) for the boninites from the Troodos Massif is reported. • Boninites from Cyprus are good geochemical analogues for the high-Mg terrains of Mercury. [ABSTRACT FROM AUTHOR]