Member Since 2001
Jill A. Marshall
Assistant Professor, Portland State University
Professional Experience
Portland State University
Assistant Professor
2023 - Present
Education
Doctorate
2015
Honors & Awards
Robert Sharp Lecture
Received December 2018
Luna B. Leopold Early Career Award
Received December 2018
Jill Marshall will receive the 2018 Luna B. Leopold Young Scientist Award at AGU’s Fall Meeting 2018, to be held 10–14 December in Washington, D. C. The award recognizes a young scientist for “a significant and outstanding contribution that advances ...
Jill Marshall will receive the 2018 Luna B. Leopold Young Scientist Award at AGU’s Fall Meeting 2018, to be held 10–14 December in Washington, D. C. The award recognizes a young scientist for “a significant and outstanding contribution that advances the field of Earth and planetary surface processes.”  
Citation

I’m delighted to present Dr. Jill Marshall as the 2018 recipient of the Luna B. Leopold Award. Jill is a relentless scholar and fearless scientist boasting substantial contributions in soil geomorphology, paleoclimate and landscape evolution, cosmogenic nuclide modeling, topographic analysis, and mechanics of biota in the critical zone. From the outset of her academic career, Dr. Marshall has demonstrated her mastery of both big-picture questions that drive our discipline and methodological details paramount to her research endeavors. Jill thrives on collaboration. Those of us fortunate enough to have been drawn into her orbit have benefited tremendously from her conceptual intuition and her ability to identify study areas and methods to test new and compelling hypotheses. Jill is highly deserving of the Leopold Award, as, like Luna, she refuses to recognize potential barriers that might otherwise separate theoretical work and field observations.

For her M.S. degree, Jill mined soil science data to demonstrate that climate can explain soil clast size distributions that are key to hillslope–channel coupling. In her Ph.D., Jill challenged the notion of steady erosion in unglaciated landscapes and used a 50-kiloyear sedimentary archive to show strong coupling between paleoenvironmental trends and paleoerosion rates. By combining paleoclimate simulations with a frost weathering model, she highlighted the surprising extent of periglacial processes in unglaciated landscapes. More recently, Dr. Marshall is tackling the problem of how tree roots penetrate, fracture, and extricate bedrock in near-surface environments. This process is illustrated in countless textbook cartoons but has been essentially untouched in the scientific literature, until now. In summary, Jill is a shining example of the interdisciplinary and deeply skilled geoscientist that funding agencies and research institutions seek to train and employ. I’m eager to see her next suite of discoveries and the research directions that she defines for our field.

—Josh Roering, University of Oregon, Eugene

Response
Thank you for the wonderful citation. I am profoundly honored to receive the Luna B. Leopold Award. It’s a testament to the extended science community that I’ve had the privilege of learning from. Together we’ve tested ideas that are bigger than any one of us. I came to geomorphology sideways, starting at community colleges while working full-time. Hired at an environmental agency, I grappled with melding information from physical and biological systems across scales. While growing into river and watershed science, I began to intersect with Bill Dietrich and Tom Dunne. Their unstinting interest in my ideas and willingness to engage my curiosity sparked a desire to learn quantitative science, leading to a journey from theory to the field and back again. Importantly, I learned that good ideas should, and could, matter more than pedigree. Leonard Sklar entrained me in the quest to tease apart controls on grain size distributions produced by hillslope processes. As we dug pits and I dug into decades of soil data, I stood intellectually and literally at the intersection of climate, tectonics, lithology, and soil production processes. I am deeply grateful to Leonard for setting no limits on how to approach a mostly unexplored problem. For my Ph.D., I traveled to the seemingly well characterized Oregon Coast Range, where Josh Roering encouraged roaming among topics and tools while modeling broad interests, kindness, and humility. As I roamed, I absorbed frameworks from disparate disciplines, ranging from paleoclimatology to forest ecology. This has served me well as I continue to explore the role of climate and rock properties on biotic and abiotic mechanisms that shape our Earth. I thank Bob Anderson, Bill Dietrich, and the Critical Zone Observatory community for invigorating postdoc mentoring; my Ph.D. lab mates; and those involved in nominating me, led by Jane Willenbring and Nicole Gasperini. —Jill Marshall, University of Arkansas, Fayetteville
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Publications
AGU Abstracts
Tall Walls and Talus Piles: Investigating the Influence of Talus and Wall Height on the Evolution of Wide Bedrock Valleys
AGU 2024
earth and planetary surface processes | 11 december 2024
Clay Robertson, Abigail L. Langston, Jill A. Marsh...
In many landscapes across the world, bedrock rivers represent the first domino to fall in the series of events required to cause broad landscape trans...
View Abstract
Rock Wall Fracture Spacing as a Potential Control on River Valley Widening, Buffalo National River, Arkansas
AGU 2024
earth and planetary surface processes | 11 december 2024
Kindle Hon, Jill A. Marshall, Abigail L. Langston
River valley widening rates are often attributed to rock wall erodibility. Here, we test the alternate hypothesis that rock wall fracture patterns, ra...
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What Controls Bedrock Valley Width? Towards a Process-based Understanding of Bedrock Valley Evolution
AGU 2024
earth and planetary surface processes | 11 december 2024
Abigail L. Langston, Jill A. Marshall, Clay Robert...
Understanding how bedrock canyons evolve into wide bedrock valleys is a frontier in geomorphology. Valley width is largely controlled by lithology and...
View Abstract
Check out all of Jill A. Marshall’s AGU Research!
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