Abstract
Using stepped heating extraction techniques, determinations of carbon and nitrogen content and δ13C and δ15N values have been obtained for selected lunar soils and breccias. Only nitrogen data have been gathered for representative splits separated by size, density and magnetic properties from 12023. A plot of the total δ13C (after terrestrial contamination is removed) versus δ15N values for bulk samples reveals little evidence for a correlation between isotopically light carbon and isotopically light nitrogen of putative ancient solar wind origin. Soil 12023 is used to examine the current interpretation for the stepped release profile of nitrogen from bulk lunar samples. Mature agglutinates, postulated by previous workers to be the host of the light nitrogen, are shown to have a very constant δ15N value which is heavy rather than light. The actual host of the light nitrogen in 12023 has not been identified. The lowest values encountered during the study were found associated with the finest soil, but none of these was as low as for some temperature steps of the bulk soil. Interpretations regarding the origin of light nitrogen, if it is not present in agglutinates, await the results of more definitive efforts to identify the host phase.
