Geology and Geophysics
Given the significant degree to which the modern Mississippi River and its tributaries have been altered through dams, levees, and diversions, it is important to understand how sediment is transported from source to sink. The objective of this dissertation is to explore how the modern Mississippi River transports sediment from its tributaries to its delta using three independent proxies. Provenance indicators have traditionally been an effective way with which to characterize sediment transport in large river systems. First, detrital U-Pb zircon dating is used to investigate modern flux and possible anthropogenic influences on coarse-grained sediment within the modern Mississippi River. Overall, results indicate that samples taken from the modern river show regional flux and possible repercussions of the Red River diversion into the Atchafalaya basin. Secondly, apatite geochemistry is used to determine its viability as an independent provenance indicator when used on detrital populations with large samples sizes. In the end, it is concluded that when quantitative analysis is used to enhance variability between samples, these results compare closely with detrital zircon U-Pb spectra. Finally, Nd and Sr samples are evaluated from a core taken within the modern Mississippi River delta. From this data, it is concluded that εNd values from the Mississippi River remain relatively stable until modern human alterations shift the geochemical signature in the top of the core.
Gregory, Brittney Anne, "The Modern Mississippi: Provenance Indicators and Human Impact" (2019). LSU Doctoral Dissertations. 4874.