24 Undergraduate Research Posters
This poster session highlights geoscience research conducted and presented by undergraduate students. Abstracts must be written by students (but may include non-student co-authors). Research topics may include any area of the earth sciences.
Thursday, 23 April 2026
8:00 AM - 5:30 PM
LMH, 5th Floor Chapel
Preliminary Analysis of Volcanic Sediment Sources in Copeland Creek, Sonoma County, CA
Paper number: 24-17
Program: Technical Sessions
Time: 8:15 AM – 8:15 AM
Authors
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Owen AnfinsonSonoma State University, Department of Geology, Rohnert Park, CA
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Tiffany Love-HutchinsSonoma State University, Department of Geology, Rohnert Park, CA
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Nicholas LopezSonoma State University, Department of Geology, Rohnert Park, CA
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Archie HealonSonoma State University, Department of Geology, Rohnert Park, CA
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Gloria HerreraSonoma State University, Department of Geology, Rohnert Park, CA
Abstract
Sources of volcanic sediment within the Copeland Creek watershed of Sonoma County, California are poorly constrained despite the creekâs location within the Sonoma Volcanics. This study integrates drone imagery, existing lidar datasets, geologic mapping, and sediment provenance analysis to improve understanding of volcanic sediment sources and transport within the Copeland Creek drainage basin.
Copeland Creek is a small tributary of the Russian River watershed that drains terrain underlain by diverse volcanic units. Sediment transported by the creek preserves a record of erosion processes, hillslope-channel connectivity, and downstream sediment delivery. We investigate volcanic sediment provenance through field-based sampling and spatial mapping of volcanic material along the active channel. Sediment samples are being collected at multiple locations along the creek to capture downstream changes in lithologic composition.
Sediments are analyzed using grain-size measurements, clast counts, and lithologic identification of volcanic fragments, with planned thin section analysis to refine source interpretations. Initial observations suggest sediments are dominated by basalt, vesicular basalt, and perlitic volcanic glass. While basaltic components are consistent with local Sonoma Volcanics units, the source of the volcanic glass remains uncertain and is a focus of ongoing mapping and analysis. The relative abundance of volcanic lithologies at each site is used to construct a preliminary provenance map of Copeland Creek.
Understanding the distribution of volcanic sediments within Copeland Creek provides insight into sediment transport pathways and erosion processes within this tributary and informs broader assessments of sediment delivery to the Russian River watershed. This study contributes to regional watershed management efforts and demonstrates the application of volcanic provenance analysis in a small watershed setting.
Geological Society of America Abstracts with Programs. Vol. 58, No. 3
doi: 10.1130/abs/2026CD-411069
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