Mid-infrared emission spectroscopy of meteorite NWA 7325: Identifying the mineralogy with a non-destructive, remote-sensing technique
Melissa Lane, Cyrena Goodrich, Noriko Kita
A polished chip of the Northwest Africa 7325 meteorite, a highly reduced, ungrouped achondrite [1-4], was analyzed using an FTIR spectrometer modified for emission measurements. The chip was roughly triangular in shape with side lengths of ~12, 12, and 16 mm. Radiance data were collected at 2 cm^-1 spectral sampling from ~2000 – 230 cm^-1 (~5 – 44 microns) in a nitrogen-purged atmosphere while the sample was maintained at approximately 70 degrees C. The radiance curves were processed to retrieve emissivity spectra of the meteorite interior. Using a spectral library of 47 different rock-forming minerals, including a range of feldspar, pyroxene, and olivine compositions, and other mineral classes, the meteorite data were spectrally unmixed in order to determine the mineralogic composition of the meteorite chip. The results indicate that the meteorite sample consists of ~77 vol. % anorthite, ~13 vol. % diopside, and ~8 vol. % forsterite. These spectral unmixing results coincide well with the mineral compositions and their modal abundances determined in other petrologic studies [1-4]. These spectral analyses and the determined minerals and modal abundances will help identify the parent body of NWA 7325, so far proposed to be either Mercury [1] or a ureilite-like asteroid [4,5].
[1] Irving, A. et al., LPSC 44, abs. 2164 (2013)
[2] Bischoff, A. et al., EPSC 8, abs. 427 (2013)
[3] Morlok, A. et al., EPSC 8, abs. 114 (2013)
[4] Goodrich, C.A. et al., LPSC 45, abs. 1246 (2014)
[5] Kita, N. et al., LPSC 45, abs. 1455 (2014)
46th Division for Planetary Sciences (DPS )Meeting
Science Schedule and Events
11 November 2014
205. Moon/Mercury Surface
Chair(s): Thomas Morgan (NASA/GSFC) and Melissa Lane (Planetary Science Institute)
10:30 AM – 11:40 AM; Arizona Ballroom 11/ 12
10:30 AM – 11:40 AM; Arizona Ballroom 11/ 12
