ENHANCED MICROBIAL PRECIPITATION OF IRON OXIDES IN DEMOPOLIS CHALK FORMATIONS

The objective of the study was to determine if microbial components are present in iron oxide concretions in the Demopolis Chalk of Mississippi. Samples were evaluated using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Confocal Microscopy at the Institute for Imaging and Analytical Technology (I²AT) at Mississippi State University and using petrographic microscopes at the Department of Geosciences. All microscopy techniques reveal evidence of microbes. Long strands of microbial filament are visible in the petrographic images of a sample containing pyrite, calcite and iron oxides. This sample also contains gypsum layers that were confirmed using XRD and SEM analyses. Sediment samples having little to no microbial evidence were analyzed and compared to SEM images of the actual burrows found at the site. SEM images display groups of filaments and debris indicating a microbial presence. The information obtained during the study could be used in fields ranging from industrial equipment design to planetary geology.