Harrison Gray, PhD
Earth's surface is shaped by the transfer of sediment across time and space. As we live on the Earth's surface, understanding this transport of sediment is key to the well-being of our species. I work on solving problems asscociated with landscapes and sediment transport using the tools of computer landscape evolution modeling and the trapped-charge phenomena known as luminescence.
Education and Certifications
Ph.D Geomorphology, University of Colorado - Boulder, 2018
M.S. Geology, Univeristy of Cincinnati, 2013
B.S. Earth Sciences, University of California - Santa Cruz, 2010
Honors and Awards
Presidential Early Career Award for Scientists and Engineers (PECASE), 2025
Science and Products
Filter Total Items: 14
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Paleoseismic results from the Alpine site, Wasatch fault zone: Timing and displacement data for six holocene earthquakes at the Salt Lake City–Provo segment boundary Paleoseismic results from the Alpine site, Wasatch fault zone: Timing and displacement data for six holocene earthquakes at the Salt Lake City–Provo segment boundary
To improve the characterization of Holocene earthquakes on the Wasatch fault zone (WFZ), we conducted light detection and ranging (lidar)‐based neotectonic mapping and excavated a paleoseismic trench across an 8‐m‐high fault scarp near Alpine, Utah, located ∼6.2–0.4 ka∼6.2–0.4 ka. Interseismic recurrence ranges from 0.2 to 1.8 ky (mean 1.2 ky). We estimate 6.5±0.7 m6.5±0.7 m of...
Authors
Scott E.K. Bennett, Christopher DuRoss, Ryan D. Gold, Richard W. Briggs, Stephen Personius, Nadine G. Reitman, Joshua Devore, Adam Hiscock, Shannon A. Mahan, Harrison J. Gray, Sydney Gunnarson, William J. Stephenson, Elizabeth Pettinger, Jackson K. Odum
Examining the relationship between portable luminescence reader measurements and depositional ages of paleowetland sediments, Las Vegas Valley, Nevada Examining the relationship between portable luminescence reader measurements and depositional ages of paleowetland sediments, Las Vegas Valley, Nevada
Portable luminescence readers are exciting new tools that have the potential to rapidly determine the age structure of late Quaternary stratigraphic columns. This is important because high-resolution age profiling can reveal details about the temporal dynamics of climate cause and ecosystem effect, often while researchers are still in the field. In this paper, we compare new portable...
Authors
Harrison J. Gray, Shannon A. Mahan, Kathleen B. Springer, Jeffrey S. Pigati
Application of a luminescence‐based sediment transport model Application of a luminescence‐based sediment transport model
Quantifying the transport history of sand is a challenging but important goal in geomorphology. In this paper, we take a simple idea that luminescence is bleached during transport and regenerates during storage, and use this as a basis to re‐envision luminescence as a sediment tracer. We apply a mathematical model describing luminescence through an idealized channel and reservoir system...
Authors
Harrison J. Gray, Gregory E. Tucker, Shannon A. Mahan
Dating of river terraces along Lefthand Creek, western High Plains, Colorado, reveals punctuated incision Dating of river terraces along Lefthand Creek, western High Plains, Colorado, reveals punctuated incision
The response of erosional landscapes to Quaternary climate oscillations is recorded in fluvial terraces whose quantitative interpretation requires numerical ages. We investigate gravel-capped strath terraces along the western edge of Colorado's High Plains to constrain the incision history of this shale-dominated landscape. We use ¹⁰Be and ²⁶Al cosmogenic radionuclides (CRNs), optically...
Authors
Melissa A. Foster, Robert S. Anderson, Harrison J. Gray, Shannon A. Mahan
On extracting sediment transport information from measurements of luminescence in river sediment On extracting sediment transport information from measurements of luminescence in river sediment
Accurately quantifying sediment transport rates in rivers remains an important goal for geomorphologists, hydraulic engineers, and environmental scientists. However, current techniques for measuring long-time scale (102–106 years) transport rates are laborious, and formulae to predict transport are notoriously inaccurate. Here we attempt to estimate sediment transport rates by using...
Authors
Harrison J. Gray, Gregory E. Tucker, Shannon A. Mahan, Chris McGuire, Edward J. Rhodes
User guide for luminescence sampling in archaeological and geological contexts User guide for luminescence sampling in archaeological and geological contexts
Luminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to...
Authors
Michelle S. Nelson, Harrison J. Gray, Jack A. Johnson, Tammy M. Rittenour, James K. Feathers, Shannon Mahan
Science and Products
Filter Total Items: 14
No Result Found
Filter Total Items: 29
Paleoseismic results from the Alpine site, Wasatch fault zone: Timing and displacement data for six holocene earthquakes at the Salt Lake City–Provo segment boundary Paleoseismic results from the Alpine site, Wasatch fault zone: Timing and displacement data for six holocene earthquakes at the Salt Lake City–Provo segment boundary
To improve the characterization of Holocene earthquakes on the Wasatch fault zone (WFZ), we conducted light detection and ranging (lidar)‐based neotectonic mapping and excavated a paleoseismic trench across an 8‐m‐high fault scarp near Alpine, Utah, located ∼6.2–0.4 ka∼6.2–0.4 ka. Interseismic recurrence ranges from 0.2 to 1.8 ky (mean 1.2 ky). We estimate 6.5±0.7 m6.5±0.7 m of...
Authors
Scott E.K. Bennett, Christopher DuRoss, Ryan D. Gold, Richard W. Briggs, Stephen Personius, Nadine G. Reitman, Joshua Devore, Adam Hiscock, Shannon A. Mahan, Harrison J. Gray, Sydney Gunnarson, William J. Stephenson, Elizabeth Pettinger, Jackson K. Odum
Examining the relationship between portable luminescence reader measurements and depositional ages of paleowetland sediments, Las Vegas Valley, Nevada Examining the relationship between portable luminescence reader measurements and depositional ages of paleowetland sediments, Las Vegas Valley, Nevada
Portable luminescence readers are exciting new tools that have the potential to rapidly determine the age structure of late Quaternary stratigraphic columns. This is important because high-resolution age profiling can reveal details about the temporal dynamics of climate cause and ecosystem effect, often while researchers are still in the field. In this paper, we compare new portable...
Authors
Harrison J. Gray, Shannon A. Mahan, Kathleen B. Springer, Jeffrey S. Pigati
Application of a luminescence‐based sediment transport model Application of a luminescence‐based sediment transport model
Quantifying the transport history of sand is a challenging but important goal in geomorphology. In this paper, we take a simple idea that luminescence is bleached during transport and regenerates during storage, and use this as a basis to re‐envision luminescence as a sediment tracer. We apply a mathematical model describing luminescence through an idealized channel and reservoir system...
Authors
Harrison J. Gray, Gregory E. Tucker, Shannon A. Mahan
Dating of river terraces along Lefthand Creek, western High Plains, Colorado, reveals punctuated incision Dating of river terraces along Lefthand Creek, western High Plains, Colorado, reveals punctuated incision
The response of erosional landscapes to Quaternary climate oscillations is recorded in fluvial terraces whose quantitative interpretation requires numerical ages. We investigate gravel-capped strath terraces along the western edge of Colorado's High Plains to constrain the incision history of this shale-dominated landscape. We use ¹⁰Be and ²⁶Al cosmogenic radionuclides (CRNs), optically...
Authors
Melissa A. Foster, Robert S. Anderson, Harrison J. Gray, Shannon A. Mahan
On extracting sediment transport information from measurements of luminescence in river sediment On extracting sediment transport information from measurements of luminescence in river sediment
Accurately quantifying sediment transport rates in rivers remains an important goal for geomorphologists, hydraulic engineers, and environmental scientists. However, current techniques for measuring long-time scale (102–106 years) transport rates are laborious, and formulae to predict transport are notoriously inaccurate. Here we attempt to estimate sediment transport rates by using...
Authors
Harrison J. Gray, Gregory E. Tucker, Shannon A. Mahan, Chris McGuire, Edward J. Rhodes
User guide for luminescence sampling in archaeological and geological contexts User guide for luminescence sampling in archaeological and geological contexts
Luminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to...
Authors
Michelle S. Nelson, Harrison J. Gray, Jack A. Johnson, Tammy M. Rittenour, James K. Feathers, Shannon Mahan