LINKING TERRACE SEDIMENTS TO LOCAL LITHOLOGY THROUGH HEAVY MINERAL ANALYSIS IN THE BUFFALO NATIONAL RIVER

Ongoing work in the Buffalo National River (BNR) has found that there are significantly different optically stimulated Luminescence (OSL) signatures for quartz grains present within the same terrace deposits of the BNR. This finding has led to questions about what can cause this variation. Heavy mineral analysis is one approach to understanding the source of the various OSL signatures. The aim of this study is to provide further insight of sediment transport through heavy mineral analysis of sandstones present in the BNR the watershed, and to determine if the different OSL signatures can be utilized as a sediment fingerprinting tool. Gaining more information of the lithology in the BNR watershed will provide a better interpretation of the geologic history and sediment transport for the midcontinental United States.

Heavy mineral analysis is a common method used to investigate sediment transportation history and provenance in sandstones. Even though this is a common method, there has been little research focused on heavy mineral assemblages of the sandstones in the BNR. The stratigraphy of the BNR is composed of sedimentary facies and includes multiple sandstone units. To gain more insight to the sedimentary history of the BNR lithology, heavy mineral analysis will be completed on sandstone samples from the Ordovician Everton Formation, the Mississippian Batesville Sandstone, and the Pennsylvanian middle Bloyd sandstone. This will be achieved by crushing sandstone samples and using tetrabromoethane (C₂H₂Br₄, density 2.96 g/cm³) to separate the heavy minerals present in each disaggregated sample. The percentage of heavy minerals in the disaggregated sample will be calculated. In addition, the heavy minerals will be identified and counted. Previous research has found zircon and tourmaline are predominant heavy minerals in sandstones of surrounding areas. Completed analyses of this project have provided interesting results and are in the process of being repeated.