(A–C) SEM-BSE micrographs of magnetite crystals in the
rim region of carbonate globules in ALH84001. (A) Imaged
through the intact surface of a freshly fractured specimen, chain of
large elongated crystals (arrow), further chains of smaller crystals
and other details in Fig. 1. (B) Energy-dispersive x-ray
spectrometry analyses of elemental composition showing position of
Fe-rich rim (detailed data are presented in Appendix 2,
which is published as supplemental data on the PNAS web site,
www.pnas.org). (C) Similar site in a resin-embedded,
sectioned, and polished specimen, one chain marked by arrow, also site
of Auger electron spectroscopy analyses. (D) Results of
analyses of areas outlined in C: squares, magnetite
crystal chains present; triangles, absent; ca, carbonate; px,
orthopyroxene.