Presentation description

This project investigates geochemical composition of fine grained mud deposits exposed in three tributary canyons: Gypsum, Clearwater and Dark Canyons along Colorado River in southern Utah. These sediments were deposited during the inundation of Lake Powell following the construction of Glen Canyon Dam in 1963 and have been recently re exposed due to prolonged drought and declining reservoir levels. The goal of this study is to determine whether the geochemical signatures of these mud deposits still reflect the distinct bedrock geology of their watersheds or whether decades of reservoir mixing have homogenized their compositions.

To explore this. we collected stratified sediment samples from each tributary and are analyzing them using X-ray fluorescence (XRF) to measure elemental composition, Scanning Electron Microscopy (SEM) to examine sediment texture and grain relationships, and Laser Grain Size Analysis (LGSA) to characterize particle size distributions.

We hypothesize that (1) if sediment provenance dominates, geochemical fingerprints will vary by tributary; (2) if post depositional mixing within the reservoir dominates, samples will exhibit similar chemical profiles across sites and (3) if stratigraphy reflects consistent depositional processes, geochemical composition will be uniform across sediment layers. Understanding these patterns is crucial for assessing contaminant mobility (e.g., heavy metals), informing sediment management strategies and evaluation ecological risks as exposed muds are remobilized by storm and river flow.

This research supports environmental monitoring and cultural preservation efforts in the Glen Canyon region, contributing to broader discussions on water resource sustainability, sediment dynamics and land management in the Colorado River Basin.