2-5 February 2016
Australia/Melbourne timezone

An $^{57}$Fe Mössbauer Study of the Ordinary Chondrite meteorite Lynch-001

Not scheduled
15m

Speaker

Ms Nancy N. Elewa (UNSW Canberra)

Description

The Lynch-001 meteorite is classified as an ordinary chondrite of the petrologic group L5-6 that has undergone ‘minor to moderate’ terrestrial weathering (A/B class). It was found in the Nullarbor desert in Western Australia in 1977 at the coordinates 31° 1' S / 127° 13' E [1]. Here, we report the characterization of the Fe-bearing phases in this chondrite using $^{57}$Fe Mössbauer spectroscopy carried out over the temperature range 13 to 295 K. The paramagnetic doublets of olivine and pyroxene dominate the spectra, accounting for 62(3)% of the spectral area at room temperature. On the basis of the room temperature quadrupole splitting of 2.93(1) mm/s we estimate the olivine composition to be Fa$_{30(5)}$[2]. Besides the olivine and pyroxene, there is a paramagnetic ferric component that amounts to 15(2)% of the spectral area at room temperature. The presence of this Fe$^{3+}$ component attests to the weathering of this meteorite. The spectrum also includes troilite (FeS) with a relative spectral area of 12(2)%, Fe-Ni metal (4(2)%) and magnetite/maghemite (7(2)%). The total relative proportion of Fe $^{3+}$ allows us to estimate the terrestrial age of Lynch-001 to be around 6,000 yr, consistent with the value of 6,700 ± 1,300 yr determined by $^{14}$C dating [3]. **References** [1] M. M. Grady, Catalogue of Meteorites, 5th ed (Cambridge University Press, 2000) p 689. [2] O. N. Menzies, P. A. Bland and F. J. Berry, Lunar Planet. Sci. XXXII, pp. 1967–1968, (2001) [3] A.J.T. Jull et al., Meteoritics & Planetary Sci. 45, 1271-1283 (2010).

Primary author

Ms Nancy N. Elewa (UNSW Canberra)

Co-author

Prof. Sean Cadogan (UNSW Canberra)

Presentation Materials

There are no materials yet.
Your browser is out of date!

Update your browser to view this website correctly. Update my browser now

×