New Technology/Old Technology: Comparing Lunar Grain Size Distribution Data and Methods

Laser diffraction technology generates reproducible grain size distributions and reveals new structures not apparent in old sieve data. The comparison of specific sieve fractions with the Microtrac distribution curve generated for those specific fractions shows a reasonable match for the mean of each fraction between the two techniques, giving us confidence that the large existing body of sieve data can be cross-correlated with new data based on laser diffraction. It is well-suited for lunar soils, which have as much as 25% of the material in the less than 20 micrometer fraction. The fines in this range are of particular interest because they may contain a record of important space weathering processes

An unusual clast in lunar meteorite MacAlpine Hills 88105: a unique lunar sample or projectile debris?

Lunar meteorite MacAlpine Hills (MAC) 88105 is a well-studied feldspathic regolith breccia dominated by rock and mineral fragments from the lunar highlands. Thin section MAC 88105,159 contains a small rock fragment, 400 × 350 μm in size, which is compositionally anomalous compared with other MAC 88105 lithic components. The clast is composed of olivine and plagioclase with minor pyroxene and interstitial devitrified glass component. It is magnesian, akin to samples in the lunar High Mg-Suite, and also alkali-rich, akin to samples in the lunar High Alkali Suite. It could represent a small fragment of late-stage interstitial melt from an Mg-Suite parent lithology. However, olivine and pyroxene in the clast have Fe/Mn ratios and minor element concentrations that are different from known types of lunar lithologies. As Fe/Mn ratios are notably indicative of planetary origin, the clast could either (1) have a unique lunar magmatic source, or (2) have a nonlunar origin (i.e., consist of achondritic meteorite debris that survived delivery to the lunar surface). Both hypotheses are considered and discussed

Data compilation task report for the source investigation of the 300-FF-1 operable unit phase 1 remedial investigation

This report provides additional information on facility and waste characteristics for the 300-FF-1 operable unit. The additional information gathered and reported includes meetings and on-site visits with current and past personnel having knowledge of operations in the operable unit, a more precise determination of the location of the Process Sewer lines and Retired Radioactive Liquid Waste Sewer, a better understanding of the phosphoric acid spill at the 340 Complex, and a search for engineering plans and environmental reports related to the operable unit. As a result of this data-gathering effort, recommendations for further investigation include characterization of the 307 Trenches to determine the origin of an underlying uranium plume in the groundwater, more extensive sampling of near-surface and dike sediments in the North and South Process Ponds to better define the extent of horizontal contamination, and detection of possible leaks in the abandoned Radioactive Waste Sewer by either electromagnetic induction or remote television camera inspection techniques. 16 refs., 4 figs., 5 tabs