Abstract Seismological observations in the lunar mantle, in conjunction with experimental knowledge on the elastic wave velocities and density of lunar mantle minerals, provide important constraints on the composition and mineralogy of the lunar mantle. Here we report elastic wave velocities and density of a lunar orthopyroxene (Mg0.84Fe0.13Ca0.03SiO3) up to 5.5 GPa and 1,273 K. The result shows that the bulk and shear moduli of orthopyroxene decrease with increasing iron content. Based on the mineral elasticity data, we modeled the P‐ and S‐wave velocities and density of petrologically suggested lunar upper mantle rock composition. The petrological lunar upper mantle rock model shows consistent seismic wave velocities with those observed in the lunar upper mantle whereas markedly lower density. Our modeling suggests an iron‐rich (Fe/(Mg + Fe) = 0.20) lunar upper mantle to explain P‐ and S‐wave velocities and density of the lunar upper mantle at 40–740 km depth.
Observations from the Little Bunker
Last updated: February 24, 2026 10:22 PM
Atmospheric CO₂
429.9 ppm
+17.3
ppm/year
Atmospheric CH₄
1946.47 ppb
+6.49
ppb/year
Global Temperature
+1.48 °C
Peak: +1.73°C
World Population
8.1 billion
+67
million/year