GEOCHEMICAL ANOMALIES AT THE WEAUBLEAU-OSCEOLA STRUCTURE, MO, A PROPOSED IMPACT SITE

The Weaubleau-Osceola structure is a proposed meteorite impact site located in St. Clair County, Missouri. Geochemical evidence may add a level of data necessary to unambiguously assign a meteorite impact origin for the structure. Eleven soil and 40 sediment samples were analyzed via XRF and ICP-AES to determine elemental concentrations. Siderophile element concentrations typical of a meteorite impact (Ni, Mn, Mo, Co, Cr) were mapped using Inverse Distance Weighted Spatial Analysis to determine the location of any anomaly. While soil samples alone show a slight anomaly associated with the impact crater, sediment samples do not show any obvious anomaly, with no patterns in high or low concentrations. This lack of anomaly in the sediment may be due to transport. Higher concentrations may be attributed to an anthropogenic source nearby or upstream. Lower concentrations may be natural background levels. There are no mafic or ultramafic rocks in the area to contribute high concentrations. Any anomaly associated with a meteorite impact is not apparent with the given data, and no conclusions can be drawn without further investigation. Finding and mapping a siderophile anomaly at the Weaubleau-Osceola structure will indicate a meteorite impact origin for the structure.