MdDermott, K.; Greenwood, R. C.; Franchi, I. A.; Anand, M. and Scott, E. R. D.
Oxygen isotopic constraints on the origin and relationship of IIE iron meteorites and H chondrites.
In: 73rd Annual Meeting of the Meteoritical Society, 26-30 July 2010, New York, NY, US.
Introduction: Although silicate inclusions are present in only about half the IIE irons so far identified (total no. about 15), these objects are highly diverse; varying from chondrule-bearing clasts to elongate ribbons of quenched basaltic melt. Models to explain the origin of IIE irons invoke either near-surface asteroidal impact processes, or impact mixing during igneous differentiation. On the basis of their similar oxygen isotope compositions, a possible relationship between the H chondrites and IIE irons has been proposed. However, this has recently been called into question because high-precision laser fluorination analysis of equilibrated H chondrites (n=9) indicates that the overlap with IIE irons is relatively limited. To improve our understanding of this important group of meteorites we are currently undertaking a detailed geochemical investigation of the silicate-bearing IIE irons.
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