Over the last two decades, Eau Claire, Wisconsin, has experienced significant urban expansion, characterized by increased residential, industrial, parking infrastructure, and a general rise in impervious surfaces. This transition from permeable natural landscape to engineered surfaces poses a direct threat to the region’s hydrologic balance by diminishing infiltration capacity. While previous land-use studies have relied on coarse resolution data (e.g., 15 - 30 m Landsat imagery) at the watershed scale, there is a critical need for localized, and high-resolution assessments of the land-cover change. This study utilizes the Google Earth Engine (GEE) platform and Environment for Visualizing Images (ENVI) software to analyze 2-meter resolution spatial National Agriculture Imagery Program (NAIP) data from 2008 and 2022. By performing a supervised classification of Land Use and Land Cover (LULC), we quantified the conversion of pervious landscapes to impervious cover. Our preliminary results indicate a measurable decline in potential infiltration areas, identifying specific “hazard zones” susceptible to increased surface runoff. These findings suggest a heightened risk for localized flooding and increased nutrient loading into local water bodies, which may exacerbate seasonal algal blooms. This research provides a vital, updated dataset for sustainable water management.
Once roughly five times the size of Lake Superior, Megalake Chad was a vast inland body of water that has drastically receded over the past 5,000 years. Building upon previous geomorphic mapping, this study aims to quantify the lake's paleo-hydrology to evaluate the environmental impacts of its rapid desiccation during the Holocene. Using Google Earth Engine (GEE) and ArcGIS, we analyzed a suite of remote sensing data, including the 30-meter Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM), alongside PALSAR and RADARSAT sensors.To further characterize the ancient lake, we generated multiple topographic and slope swath profiles across north-to-south transects of the basin. These analyses are designed to constrain the shoreline and depth extent of the lake to facilitate future volumetric modeling. Because much of the northern basin lies beneath the Sahara Desert, radar sensors are being employed to reveal critical subsurface drainage systems overlooked by surface analyses alone. By integrating satellite topography and subsurface radar data, this research establishes a framework to reconstruct Megalake Chad's ancient capacity. Ultimately, quantifying this massive water loss will provide a deeper understanding of the region's paleoenvironmental shifts and the profound ecological consequences of a disappearing megalake.
Climate change is impacting water resources globally. In the US Mountain West, warming is pushing watersheds beyond historical hydroclimate conditions and altering snowpack, groundwater recharge, and stream baseflow. This project investigates intermittent groundwater discharge, i.e., flow that pulses following snowmelt and ceases during late summer low-flow conditions. Here we address three research questions to better understand shifting ecohydrological baselines: (1) What groundwater flow path distributions support intermittent flow? (2) What is the chemical signature of intermittent groundwater discharge? And (3) How do groundwater age and flow duration relate to landscape geomorphological characteristics? The study will be conducted in the Sagehen Creek Basin, CA, a well-instrumented Sierra Nevada watershed with long-term climate, streamflow, and groundwater records. We will sample five intermittent groundwater sites for age-dating using CFCs and SF6, analyze major ion chemistry and field water quality parameters, deploy in-situ loggers to record flow persistence or absence, and compute high-resolution terrain metrics to evaluate landscape controls. Pending results and analysis will provide insight into how climate-driven changes in recharge and snowpack influence groundwater flow paths, water quality, and the resilience of mountain groundwater systems.
The Black Hills Tomahawk obsidian deposit remains enigmatic; two independent geochron studies reveal significant age differences: 55 Ma (Kirchner, Science 1977) vs 10 Ma (Redden et al., Science 1983); both are problematic for preserving unaltered glass. The deposit consists of a dense network of anastomosing perlitic veins (0.1-3mm) encapsulating regions of unaltered glass (10 µm) chemically homogenous border zone separating the unaltered glass from the hydrous veins. This behavior resembles chemical zoning preserved in high-temperature phenocrysts, with distinct core, mantle, and rim compositions. Major elements show opposite mobility when comparing the unaltered glass to the veins and border zone: the behavior of Al, Na, and K (+3/+1 cations) is inverse to Si, Ca, and Ba (+4/+2 cations) with a 1:1 anticorrelation. This behavior differs from multiple studies on cation diffusion in silicate melts and high temperature glasses, which document smooth concentration gradients. Our results suggest cations in glasses at temperatures below the glass transition temperature are frozen into fixed sites, and subsequent mobilization requires coupled multi-variate substitutions to accommodate size and charge constraints.
During the Neoarchean ~2.5 Ga, Earth underwent a notable transition in tectonic processes. The rocks studied in this research offer a highly uncommon view into the transition period of tectonics as the Earth shifted from higher-temperature, ductile conditions to the colder, more brittle processes we observe in the modern day. The project employs multiple geologic methods to enhance our understanding of geodynamic history and crustal architecture during the cratonic assembly of the Superior Province in the Neoarchean era. Research examines a series of coeval magmatic units within the Vermilion and Shebandowan greenstone belts, located in northeastern Minnesota and western Ontario. These magmatic suites were formed during transitional tectonic styles and may have inherited crust and mantle conditions during their formation. Geochemical differences between these magmatic systems are described by compiling new and historic data with qualitative mineral descriptions from thin sections and hand samples. Major and trace element abundances were determined through X-Ray Fluorescence (XRF). In addition to addressing tectonic reconstructions of Neoarchean Earth, the resulting data can constrain gold-forming magmatic-hydrothermal intrusive systems.
Komatiites are ultramafic magmas which only formed during the Archean because of hotter mantle conditions. Because they are an extinct form of magmatism, their volcanology and environmental interactions are poorly constrained. Komatiites of the 2.7 Ga Shebandowan greenstone belt, near Thunder Bay, Ontario, Canada, are particularly well-exposed and provide a unique opportunity to describe komatiite-sediment interactions and the formation of peperites – a product of lava and unconsolidated, water-saturated sediment interactions. The contact between komatiites and argillites and brecciated textures were described in detail to compare with modern magma-sediment mingling products. In the contact zone between the komatiites and argillites, samples have an argillite matrix with angular shaped aphanitic komatiite pieces. When fractured, the komatiite would accommodate sediment, creating wispy flow like structures and globular pyrite. This creates a “mixed” look to the argillite with fractures cutting across its surface. Peperites give insight into how komatiites and other high-temperature lavas may interact with wet sedimentation during emplacement. Additionally, heated basin waters can produce hydrothermal activity and crustal assimilation within komatiites that may result in mobilization of metals and formation of sulfide mineral deposits.
