Effect of sulfur on sound velocity of liquid iron under Martian core conditions.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32404909.
- Also identified by DOI 10.1038/s41467-020-15755-2 and PMC identifier 7220916.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Sulfur has been considered to be a predominant light element in the Martian core, and thus the sound velocity of Fe-S alloys at relevant high pressure and temperature is of great importance to interpret its seismological data. Here we measured the compressional sound velocity (V<sub>P</sub>) of liquid Fe, Fe<sub>80</sub>S<sub>20</sub> and Fe<sub>57</sub>S<sub>43</sub> using ultrasonic pulse-echo overlap method combined with a Kawai-type multi-anvil apparatus up to 20 GPa, likely corresponding to the condition at the uppermost core of Mars. The results demonstrate that the V<sub>P</sub> of liquid iron is least sensitive to its sulfur concentration in the Mars' whole core pressure range. The comparison of seismic wave speeds of Fe-S liquids with future observations will therefore tell whether the Martian core is molten and contains impurity elements other than sulfur.