Odd spots on the lunar farside could be ancient material from deep inside
DENVER — For the first time in decades, astronomers have identified a new rock type on the moon. Tucked away on the lunar farside, unseen until a space probe spotted its odd mineralogy, are a few deposits of what is probably ancient material that originated deep inside the moon.
“These are very unusual areas,” said Carle Pieters, a planetary geologist at Brown University in Providence, R.I., who reported the finding November 2 at a meeting of the Geological Society of America.
Pieters has dubbed the new rock type OOS, because it is rich in the minerals orthopyroxene, olivine and spinel. Lunar scientists are particularly intrigued by the amount of spinel in the rock; every other part of the moon has only trace amounts. On Earth, in larger chunks, spinel is a gemstone prized in such collections as the British crown jewels.
The discovery comes from the Chandrayaan-1 mission, an Indian probe that orbited the moon for 10 months in 2008–200