ACFER 182 CHONDRULES GIVE EVIDENCE FOR DIRECT CONDENSATION OF ENSTATITE-RICH

VARELA M.E.; ZINNER E; KURAT G; MAGNELLI D.

Houston

Conferencia; 42nd Lunar and Planetary Science Conference; 2011

NASA

Acfer 182 is a member of the CHcarbonaceous chondrites as introduced by Bischoff etal., [1]. The CH chondrites are characterized -amongother features- by 1) a depletion a moderately volatileand highly volatile elements [e.g.,2-3], 2) small size ofchondrules (<90 ìm), with refractory inclusionsmaking up a small fraction [1]. The low abundance ofvolatile and moderately volatile elements in chondrulesin the CH chondrites could be the result of theirformation by gas-liquid condensation in an impactvapour cloud [4], a condensation signature ofchondrule precursors [5], or a sign that chondruleswere efficiently removed from the chondrule-formingregion prior to condensation of these elements [6].Although extensive studies were performed onchondrules of the CH-like chondrites [e.g., 6-11],those on Mg-rich cryptocrystalline (CC) chondrulesare scarce [e.g., 6-7]. Here we report the results ofmajor and trace element studies of some CCchondrules in Acfer 182