Mineralogy and Petrology of New Antarctic Nakhlite MIL 03346

Introduction: Among the ~1300 meteorites returned from Antarctica by the 2003-2004 ANSMET expedition was a 715g nakhlite, MIL 03346, recovered from the Miller Range. Samples of this meteorite were distributed to investigators on December 16, 2004. We were allocated PTS MIL 03346,63,100. This abstract is our preliminary report on the mineralogy and petrology of this important new sample. Petrography: Like other nakhlites, MIL is an olivine-bearing clinopyroxene cumulate with a darkcolored, fine-grained intercumulus mesostasis. The clinopyroxene grains are subhedral to euhedral prisms, and often appear elongated. Optical photomicrographs of MIL 03346 can be seen in the on-line JSC Antarctic Meteorite Newsletter at: http://www-curator.jsc.nasa.gov/antmet/amn/amnaug04/petdes2.htm. To obtain modal abundances, we used the ratio ([Fe+Mg+Ca] / Si) and the Ti concentration obtained from whole-section elemental maps to classify each pixel as olivine, pyroxene, mesostasis, or Ti-magnetite. The resulting phase map is shown in Fig. 1, and the ensuing mode is given in the caption.