“These are very unusual areas,” said NLSI team member 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 name “spinel” is derived from the Greek word for “spark,” referring to its fiery red color. Transparent red spinel was sometimes called “spinel ruby” as it was confused with actual rubies in the past. Within Great Britain’s Crown Jewels are the “Black Prince’s Ruby,” and “Timur Ruby,” but both of these stones are actually transparent red spinel.
The discovery comes from a NASA instrument, the Moon Mineralogy Mapper or M3. By studying how much light was reflected from various parts of the lunar surface, and at what wavelength, M3 analyzed the moon’s mineralogical makeup in unprecedented detail.
“It is the first fully capable spectrometer flown to the moon,” said lunar scientist Thomas McCord of the Bear Fight Institute in Winthrop, Wash. Last year, using M3, Pieters and her colleagues reported finding spectral evidence of water on the moon.
Deep within a basin called Moscoviense, M3 spotted areas where light was being strongly absorbed at a wavelength of 2 micrometers. That particular absorption is an almost certain sign that magnesium-rich spinel is present, said Pieters.
How the material got there remains something of a mystery. Other images of the same part of Moscoviense show that the surface looks undisturbed, with smooth soil all around. The absence of any impact craters suggests that the spinel-rich areas must have been on the surface for a long time.
Pieters’ team is now looking for more of the spinel-rich rock in other parts of the moon. They have already spotted the rock in one location other than Moscoviense, she said.
Read the full article at Science News.
Posted by: Soderman/NLSI Staff