کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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6430477 | 1634796 | 2012 | 6 صفحه PDF | دانلود رایگان |
The first unambiguous global distribution of Ca on the Moon has been revealed by the Kaguya Gamma-Ray Spectrometer. The observation of the 3737Â keV gamma rays from 40Ca with a high energy resolution Ge detector, corrected for fast neutrons, improved greatly our confidence in these remote sensing data. While the derived Ca abundance generally confirms the mare-highland dichotomy, we found that the eastern mare regions such as Crisium, Nectaris, and Fecunditatis exhibit unexpected high Ca abundances. This may be explained by regional concentrations of high-Ca clinopyroxene. Our Ca map also shows that the lowest CaO abundance found in the returned samples (â¼8Â wt%) may actually be common in Oceanus Procellarum, suggesting the possible sampling bias of Apollo and Luna missions. These observational results on Ca serve as a complementary criterion for better characterization of mare regions on the Moon.
:⺠Global distribution of Ca on the Moon is derived from Kaguya GRS data. ⺠Observation by high precision Ge detector greatly improved confidence in measurement. ⺠Ca was found to be more abundant in the east mare region than in the west. ⺠Selective concentration of high-Ca pyroxene in the eastern mare region is implied. ⺠Ca provides a complementary criterion to characterize the lunar thermal history.
Journal: Earth and Planetary Science Letters - Volumes 353â354, 1 November 2012, Pages 93-98