Abstract:

Element abundances of lunar surface material is one of the important clues to study the geologic history of the Moon. China’s Chang’E-2 (CE-2) lunar orbiter carried an X-ray spectrometer (XRS) to map the element abundances on the lunar surface. During seven months XRS observation to the lunar surface, several events of solar flares occurred. The X-ray solar monitor onboard recorded simultaneous spectra of solar X-ray. In this paper, the XRS data obtained during an M solar flare event occurred on Feb. 16, 2011 are selected for quantitative inversion of the element abundances, and the contents of Mg, Al, Si, Ca and Fe in Oceanus Procellarum region on the nearside of the moon are presented. The comparison of the element contents from six regions found that from south northwards, the Si content along the orbital track is increasing. It might reflect the different composition of the erupted lavas during the filling history of the maria basins. The region II has higher Fe content than the other five regions. However, the Ca, Mg, and Al contents are lower than those from the other 5 regions. It suggests that the surface material in the region II is the least contaminated by the highland material.The average abundances of the elements obtained in Oceanus Procellarum are Mg 7.3%, Al 8.4%, Si 15.8%, Ca 6.0%, Fe 18.6%, respectively.Finally,we also discussed the factors that influence the accuracy of the inversion of element abundances.

Key words:  quantitative inversion, elemental abundance, X-ray spectrometer, Chang’E-2, Oceanus Procellarum, Moon