Reexamination of Early Lunar Chronology With GRAIL Data: Terranes, Basins, and Impact Fluxes ...

• Main Authors: Evans, Alexander J., Andrews-Hanna, Jeffrey C., Head, James W., Soderblom, Jason M., Solomon, Sean C., Zuber, Maria T.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Columbia University 2018
• Subjects: Moon; Lunar geology; Geochemistry; FOS: Earth and related environmental sciences; Impact craters; Aitken; South Pole; South pole
• Online Access: https://dx.doi.org/10.7916/d8-9k87-2b47; https://academiccommons.columbia.edu/doi/10.7916/d8-9k87-2b47

Flooding of the lunar surface by ancient mare basalts has rendered uncertain the ages of lunar geochemical terranes and several impact basins. Here we combine craters having recognizable surface expressions with craters identified only by their gravitational signatures in Gravity Recovery and Interior Laboratory data to reassess the chronological sequence of lunar impact basins and the ages of major lunar geochemical terranes. Our results indicate that although volcanically flooded regions are deficient in craters with diameters greater than 20 km by more than 50% relative to unflooded regions, craters with diameters greater than 90 km can be readily recognized either by topography or by gravity anomaly. On the basis of the areal density of craters with diameters greater than 90 km we conclude that (1) the Serenitatis basin could be as young as the Imbrium basin; (2) the areal density of craters within the Procellarum KREEP Terrane is significantly lower than that for the South Pole‐Aitken basin and the ...