Author(s): Levi Hawks
Mentor(s): Alex Tye, Alyssa Abbey
Institution UTech
Abstract: The Rio Grande Rift represents a unique setting for understanding tectonic extension and sedimentary basin evolution. Studying this geological phenomenon provides valuable insights into how tectonic forces shape sedimentary deposits over time, offering a window into past depositional environments and rift evolution. This study focuses on constraining the basin evolution of the Dry Union and Santa Fe Formations and their relationship to Rio Grande faulting, aiming to better understand the sedimentary and tectonic history of the area. Through collecting samples, conducting clast counts, and measuring intervals of strata, we are able to provide a comprehensive dataset that helps better understand the complex geological history of the area. Fieldwork involved extensive measurements and sampling across multiple locations in the Rift, with sections logged in areas containing large exposures of the Dry Union and Santa Fe formations. As part of this work, I am digitizing stratigraphic columns collected for the project, including information on grain size, bed thickness, and sedimentary structures. Interpreting these columns allows us to better understand the sedimentary environments within each formation, revealing patterns such as changes in depositional energy and shift in sediment transport. Grain-size variations in the stratigraphic columns suggest variable energy conditions within both formations, with coarser intervals indicating periods of high-energy deposition, and finer intervals reflecting periods of low-energy deposition. These stratigraphic columns will provide a basis for analyzing other datasets, including the lithology, clast counts, and sediment texture and composition, offering further insight into the provenance of sediments, and depositional settings of these formations. Collected samples are being prepared and processed for zircon mineral extraction to facilitate radiometric dating, which will establish a temporal framework for the Dry Union and Santa Fe formations. The interpretation and digitization of these stratigraphic columns will contribute to a broader understanding of the depositional and tectonic history of the Rio Grande Rift. By transforming raw field data into detailed digital logs, this work will provide a valuable and accessible resource that captures the depositional environments and sediment transport patterns across the Rift. The broader understanding of the region's stratigraphy, along with absolute dating, will allow us to reconstruct the sequence of tectonics and sedimentary events that define the area. Ultimately, these findings will contribute to a clearer picture of rift basin evolution, which have implications for Earth resources, geologic hazards, and crustal dynamics.