Collaborative Research: How are Flood Basalts Fed? A Textural Investigation of the Chief Joseph Dike Swarm

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).

Flood basalts are the Earth’s most extensive expressions of volcanism. The eruption and emplacement of these voluminous magmas have been linked to global climate shifts and many extinction events. The Columbia River Flood Basalts in Oregon, Washington, Idaho, and Nevada are the most recent and best-preserved example of this voluminous volcanic activity.

It is believed that degassing during their eruption 17-14 million years ago influenced global temperatures. A key aspect to understanding magmatic systems is deciphering how the magma is transported from depth to surface. At the Chief Joseph Dike Swarm in Oregon, a portion of the magmatic plumbing system of the Columbia River Flood Basalts is preserved and exposed.

While the transport mechanism for these magmas is well understood (i.e., sheet magmatism), the style and timing of magmatism is poorly constrained. Namely, were the Chief Joseph Dikes produced through single-pulse events or grown through time as a series of magmatic pulses where each of them contributed with tectonic deformation and degassing? Detailing the mechanism of transport and emplacement could constrain the rates of surface deformation and volatile release during magmatism.

This study will utilize relatively fast, simple, and resource-light methodologies that will inform us of the dike emplacement and growth mechanisms by studying in great detail the crystal textures recorded in the dikes themselves. This team’s research project was designed from the ground up as an unparalleled research experience for underrepresented minority (URM) undergraduate students who will be recruited to participate in the research and dissemination process.

This research is built intentionally to contribute to making the geosciences a diverse, equitable, and inclusive discipline by promoting the development of future leaders and mentors for subsequent students in STEM research and education. The program will benefit the URM student cohorts with the knowledge, motivation, and inspiration to pursue focused science careers to solve US-national and global challenges.

This project will investigate the tectonomagmatic evolution of the Columbia River Flood Basalts (CRFB), as recorded within the Chief Joseph Dike Swarm (CJDS). The team will develop and disseminate a technique that uses Electron Backscatter Diffraction (EBSD) to identify dike emplacement style using textural analyses. Analyses of dike centers will be performed on a statistically significant number of dikes to meaningfully constrain the actual proportion of single-event and pulsed emplacement styles.

Dike-center textural analyses will be calibrated using field observations and a subset of detailed textural profiles collected across dikes to identify the overall cooling history. The information generated by the proposed work will address long-standing questions surrounding the generation of space to accommodate hundreds to thousands of dikes with considerable average thicknesses.

This will impact future research by generating a detailed database of dike textures and morphologies that will allow future comparisons with other CRFB dike swarm systems and cross-comparison with other dike swarms worldwide. Results will provide insights into magma transport efficiency through the crust and the relationship between tectonics and magmatism.

Characterizing the textures of pulsed assembly of dikes or dikes that experienced sustained high Reynolds Number flow will add to our overall understanding of magmatic plumbing systems and their connection to mineralization zones and hydrothermal fields. Furthermore, the project will create linkages with education organizations in the state of Georgia.

Researchers will train and professionally develop six Underrepresented Minority (URM) student research scientists over three years. The project will broaden the participation of URMs in geosciences as we will fully leverage the existing student populations from Historically Black Colleges and Universities and Minority-Serving Institutions in Georgia.

The program will benefit the URM student cohorts with the knowledge, motivation, and inspiration to pursue focused science careers to solve US-national and global challenges. More importantly, this research is built intentionally to make geosciences a diverse, equitable, and inclusive discipline. Their mentoring experience is built around creating a welcoming environment with comprehensive guidance by relatable mentors and academic socialization, which have proven to be integrative tools for URMs.

They want to foment the extraordinary untapped talent that URM students bring to geosciences. To do this, researchers need to work towards transformative change in the way they plan their research. This team believes that their program design strives to bring justice, diversity, and inclusion to the field of geoscience.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.