Alteration Products and Secondary Minerals in Martian Meteorite Allan Hills 84001

The martian meteorites contain alteration products and secondary minerals that are a critical part of understanding their near-surface histories on both Mars and Earth. In some martian meteorites, suspected martian preterrestrial alteration products can be distinguished from terrestrial weathering effects Using scanning electron microscopy (SEM), field emission SEM (FE-SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray analysis (EDS), we are studying natural fracture surfaces of ALH 84001 chips, including samples from both the interior and the exterior of the meteorite. Exterior samples include fusion crust surfaces, which are important in determining the extent of terrestrial weathering of meteorites. The focus of this study is weathering features and secondary minerals other than the distinctive carbonate globules that continue to be studied by many researchers.