GRAIL gravity constraints on the vertical and lateral density structure of the lunar crust

Jonathan Besserer , Francis Nimmo (1) , Mark Wieczorek (2) , Renee Weber (3) , Walter Kiefer (4) , Patrick Mcgovern (4) , Jeffrey Andrews-Hanna , David Smith (5) , Maria Zuber (5)

1 Department of Earth and Planetary Sciences [Santa Cruz]
2 IPGP (UMR_7154) - Institut de Physique du Globe de Paris
3 MSFC - NASA Marshall Space Flight Center
4 LPI - Lunar and Planetary Institute [Houston]
5 EAPS - Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge]

We analyzed data from the Gravity Recovery and Interior Laboratory (GRAIL) mission using a localized admittance approach to map out spatial variations in the vertical density structure of the lunar crust. Mare regions are characterized by a distinct decrease in density with depth, while the farside is characterized by an increase in density with depth at an average gradient of ∼35 kg m −3 km −1 and typical surface porosities of at least 20%. The Apollo 12 and 14 landing site region has a similar density structure to the farside, permitting a comparison with seismic velocity profiles. The interior of the South Pole-Aitken (SP-A) impact basin appears distinct with a near-surface low-density (porous) layer 2-3 times thinner than the rest of the farside. This result suggests that redistribution of material during the large SPA impact likely played a major role in sculpting the lunar crust.

Domaines: Planétologie

Jonathan Besserer, Francis Nimmo, Mark Wieczorek, Renee Weber, Walter Kiefer, et al.. GRAIL gravity constraints on the vertical and lateral density structure of the lunar crust. Geophysical Research Letters, 2014, 41 (16), pp.5771-5777. ⟨10.1002/2014GL060240⟩. ⟨hal-02458599⟩