This award supports studies to obtain high precision bulk and trace element and mineral chemistry data on a large suite of Antarctic ordinary chondrite meteorites. These data will serve the dual purpose of proper characterization of these samples and determination of the reality of resolvable compositional differences between Antarctic finds and non-Antarctic observed falls. This work will include high-precision instrumental neutron activation analysis studies of 25 elements in 24 Victoria Land H- chondrites. To eliminate run-specific analytical biases, H- chondrite falls will be included in each neutron activation run, and to improve precision, each meteorite will be analyzed in duplicate. The electron probe data will focus on the existence of additional ordinary chondrites with properties intermediate between those of established groups. These data will help in determining the existence of additional ordinary chondrite groups.