8 Apr. 2011

 

A new meteoritic mineral

 

It's been called Wassonite and is made up of only sulphur and titanium. These elements form a unique crystal structure with such tiny dimensions (measuring only 50x450 nanometres, 100th the width of a human hair) that its discovery required the transmission electron microscope at NASA's Johnson Space Center in Houston (also able to determine chemical composition).
This new mineral was found within the matrix, also containing other unidentified minerals, of the meteorite called "Yamato 691". This is an enstatite chondrite, found in December 1969 on the ice of the Yamato Mountains in the Antarctic, by members of the Japanese Antarctic Research Expedition. This was actually the first such expedition in the Antarctic and that recovered a total of 9 specimens. Subsequent American and Japanese expeditions recovered over 40,000 specimens, including extremely rare Lunar and Martian meteorites.
1969 was an important year for the study of extraterrestrial rocks: as well as the fall of the Allende and Murchison meteorites (containing amino acids) it was the year that Apollo 11 returned samples of Lunar rocks. Only with modern technology can the microscopic inclusions in these rocks be studied and unexpected discoveries be made, like the identification of a new mineral, accomplished by a team of researchers led by Keiko Nakamura-Messenger.
The new mineral will now be added to the list of 4,500 officially recognised by the International Mineralogical Association. The name chosen, Wassonite, honours John T. Wasson, professor at the University of California, Los Angeles (UCLA), renowned for his important work on meteorites and impact craters.
The study of the Wassonite crystal, as well as the other unidentified minerals found in Yamato 691, still ongoing, will provide valuable information about the conditions that prevailed at the epoch of formation of our Solar System.

 

by Michele Ferrara & Marcel Clemens

credit: NASA's Johnson Space Center