Year: 2025
Type: article
Abstract: The Martian mantle is considered to have a higher Fe/Mg ratio than the Earth's mantle. Ringwoodite, γ‐(Mg,Fe)2SiO4, is likely the dominant polymorph of olivine in the core‐mantle boundary (CMB) region of Mars. We synthesized anhydrous iron‐rich ringwoodite with molar Mg/(Mg + Fe) = 0.44 and determined its thermal equation of state up to 35 GPa and 750 K by synchrotron X‐ray diffraction. Using a third order Birch‐Murnaghan equation of state, we obtain KT0 = 182 (3) GPa, K′ = 4.6 (2), and α0 = 3.18 (6) × 10−5 K−1. Using these results and an updated mineralogical model with an iron‐rich composition of Mg/(Mg + Fe) = 0.75 for the Martian mantle, we estimate ∼1900 K for the temperature of the D1000 seismic discontinuity inside Mars. The resulting adiabat predicts a warm aerotherm, which could explain the presence of partial melt at the CMB of Mars recently detected with seismic data from the 2019 InSight mission.
Source: Geophysical Research Letters
DOI: 10.1029/2024gl109666
Authors: Fei Wang, Hannah J. Bausch, Laura L. Gardner, Dongzhou Zhang, Katherine Armstrong, Aaron S. Bell, Jiyong Zhao, Ercan E. Alp, Steven D. Jacobsen
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,190
Awards: G102163711, Superdeep Diamonds from the Transition Zone and Lower Mantle, GEOSOILENVIROCARS: A NATIONAL RESOURCE FOR EARTH, PLANETARY, SOIL AND ENVIRONMENTAL SCIENCE RESEARCH AT THE ADVANCED PHOTON SOURCE, Facility Support: GeoSoilEnviroCARS: A National Resource for Earth, Planetary, Soil and Environmental Science Research at the APS, Consortium for Materials Properties Research in Earth Sciences (COMPRES): National Facilities and Infrastructure Development for High-Pressure Geosciences Research
OpenAlex ID: W4407137455