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Dryad

Data from: Electrical properties of alkaline earth sulfides and implications for the interior of mercury

Data files

Jan 30, 2025 version files 35.34 KB

Abstract

Alkaline earth sulfides are possibly abundant in the mantle of Mercury, and knowledge of their melting and transport properties is needed to investigate the structure of the planet. We report electrical experiments at 2 and 5 GPa and up to ~2400 K on analogs of natural sulfides, i.e., impurity-bearing Ca1-xMgxS. Electrical conductivity increases nonuniformly with temperature, with no systematic effect of composition. Below 1700 K, the conductivities span a wide range, whereas at higher temperatures the samples show a convergence to a range of ~0.5-7 S/m at 1800 K and 5 GPa. The complex conductivity trends reflect contributions from divalent cations, alkali metal and carbon impurities, which would similarly contribute to the conductivity of Mercury's crust and mantle. Melting is identified by a jump in conductivity, occurring between ~1850 and 2100 K at 5 GPa. These low temperatures are consistent with the presence of impurities. Using electrical studies on relevant silicate minerals and petrological observations, we develop electrical conductivity-depth profiles of Mercury's mantle. Depending on the interconnectivity of the sulfide phase, the conductivity at the base of the mantle containing 8 vol.% sulfide ranges from ~0.2 to > 8 S/m. Our results can be tested with future observations from the ESA-JAXA Bepi-Colombo mission.