PT  - JOURNAL ARTICLE
AU  - Ono, Takayuki
AU  - Kumamoto, Atsushi
AU  - Nakagawa, Hiromu
AU  - Yamaguchi, Yasushi
AU  - Oshigami, Shoko
AU  - Yamaji, Atsushi
AU  - Kobayashi, Takao
AU  - Kasahara, Yoshiya
AU  - Oya, Hiroshi
TI  - Lunar Radar Sounder Observations of Subsurface Layers Under the Nearside Maria of the Moon
AID  - 10.1126/science.1165988
DP  - 2009 Feb 13
TA  - Science
PG  - 909--912
VI  - 323
IP  - 5916
4099  - http://science.sciencemag.org/content/323/5916/909.short
4100  - http://science.sciencemag.org/content/323/5916/909.full
SO  - Science2009 Feb 13; 323
AB  - Observations of the subsurface geology of the Moon help advance our understanding of lunar origin and evolution. Radar sounding from the Kaguya spacecraft has revealed subsurface layers at an apparent depth of several hundred meters in nearside maria. Comparison with the surface geology in the Serenitatis basin implies that the prominent echoes are probably from buried regolith layers accumulated during the depositional hiatus of mare basalts. The stratification indicates a tectonic quiescence between 3.55 and 2.84 billion years ago; mare ridges were formed subsequently. The basalts that accumulated during this quiet period have a total thickness of only a few hundred meters. These observations suggest that mascon loading did not produce the tectonics in Serenitatis after 3.55 billion years ago. Global cooling probably dominated the tectonics after 2.84 billion years ago.