Discovery of Olivine in the Nili Fossae Region of Mars

Hoefen, Todd M.
Clark, Roger N.
Bandfield, Joshua L.
Smith, Michael D.
Pearl, John C.
Christensen, Philip R.

¹U.S. Geological Survey, Denver, CO 80225, USA.
²Arizona State University, Tempe, AZ 85287, USA.
³Goddard Space Flight Center, Greenbelt, MD 20771, USA.

*To whom correspondence should be addressed. E-mail: [email protected]

Supporting Online Material: www.sciencemag.org/cgi/content/full/302/5645/627/DC1; Materials and Methods; Table S1; References and Notes

25 July 2003; accepted 23 September 2003

Science 302(5645):p 627-630, October 24, 2003.

We have detected a 30,000-square-kilometer area rich in olivine in the Nili Fossae region of Mars. Nili Fossae has been interpreted as a complex of grabens and fractures related to the formation of the Isidis impact basin. We propose that post-impact faulting of this area has exposed subsurface layers rich in olivine. Linear mixture analysis of Thermal Emission Spectrometer spectra shows surface exposures of 30% olivine, where the composition of the olivine ranges from Fo₃₀ to Fo₇₀.