March BRGS Meeting: A Quantitative Framework for Interpreting the Stratigraphic Origin of the Mississippi River Valley Alluvial Aquifer

Sedimentary architecture provides key insights into how surface processes shape the stratigraphic record. Here we present a quantitative reconstruction of the Mississippi River Valley alluvial aquifer (MRVA), a major Quaternary glaciofluvial system, using more than 75,000 borehole records across the Lower Mississippi Valley. Through an interval kriging–based geostatistical workflow, we develop a three-dimensional hydrostratigraphic model that maps the distribution of graveliferous sands, fine-medium sands, and clay and silt deposits, capturing the basin-scale stratigraphic imprint of Quaternary depositional processes. Our analysis suggests that MRVA stratigraphy reflects the combined influence of glacio-eustatic cycles and regional geodynamic forcing, as evidenced by pre-Wisconsinan postglacial sediments and localized aquifer thickening. Faulting and salt tectonism enhanced glacial entrenchment, promoting accommodation and sediment preservation. A regional graveliferous top surface demarcates the Pleistocene–Holocene transition and serves as a stratigraphic marker of landscape reorganization following postglacial climatic and hydrologic shifts. This study demonstrates that integrating dense borehole datasets with geostatistical methods can quantitatively resolve basin evolution and depositional dynamics. The MRVA stratigraphy records the coupled effects of glacial entrenchment and tectonic activity on valley formation, preserving both environmental signals and zones of stratigraphic reworking. By linking sedimentary patterns to their formative processes, our results advance the understanding of alluvial aquifer development and provide a reference for interpreting hydrostratigraphic architecture, hydrologic function, and sustainability in large fluvial systems worldwide.

Yuqi Song, Ph.D., P.E., is a Postdoctoral Researcher in the Department of Civil and Environmental Engineering at Louisiana State University and the Louisiana Water Resources Research Institute. Her research focuses on hydrogeology, quantitative subsurface characterization, and groundwater modeling, with an emphasis on integrating geological, geophysical, and hydrological data to understand the structure and hydrologic function of large aquifer systems. Yuqi received her Ph.D. in Civil Engineering from Louisiana State University in 2025. Prior to that, she earned her M.S. degree in Civil Engineering from Iowa State University in 2017. She also holds two bachelor’s degrees: a B.S. in Civil Engineering from Iowa State University and a B.S. in Environmental Engineering from Lanzhou Jiaotong University, China, both awarded in 2015.