Lewis Cliff 87057: A new metal-rich E3 chondrite with similarities to Mt. Egerton, Shallowater and Happy Canyon

The Antarctic meteorites LEW87057, LEW87220, LEW87223, LEW87234, LEW87237, and LEW87285 were described as paired E3 chondrites by Brian Mason (Antarctic Meteorite Newsletters, 12(1) and 15(1,2)). LEW87223 is texturally unusual, containing abundant chondrules and jagged troilite grains which are enclosed in metal. Our INAA data show that the siderophile element abundance in two splits of LEW87223 are higher than the EH range, while chalcophile elements (Cr excepted) are highly depleted. Mineral compositions are unlike those normally found in EH or EL chondrites or aubites, and in some respects resemble those of several anomalous enstatite meteorites such as Shallowater, Mt. Egerton, and Happy Canyon. The bulk and mineral compositions are consistent with the addition of EL chondrite metal to an EL3 chondrite with the removal of sulfides other than troilite which is now Cr-rich. We suggest that this meteorite is an EL3 chondrite into which metal was introduced and sulfides redistributed during an event involving impact melting and brecciation.