Shannon Mahan
My work focuses on the geochronology and associated dosimetry of luminescence dating, with the goal of understanding when, how, and the rates at which mineral grains acquire (and lose!) their luminescence signal.
I graduated from Adams State University (Colorado) with a B.S. in Geology in 1987 and was immediately hired into the USGS in April 1987. For those of you that are counting, this makes me the end of the “baby boomers” and working well into my third decade with the USGS. My career has been as varied as my interests, as I have worked in radiogenic isotopes, hydrology, stable isotopes, gamma spectrometry, and luminescence. I have been the USGS Luminescence Geochronology Lab Director since 1997 and routinely work on 20 to 30 projects during a year throughout the USGS mission areas.
Over the past 40 years, luminescence dating has become a key tool for dating sediments of interest in geologic, paleontologic, and archeologic research and this is my obvious scientific interest. Luminescence is also used to date paleoseismology sites, fluvial terraces (including paleoflood deposits), eolian deposits, and is increasingly used to calibrate wildfire temperatures, sediment transport processes, and thermochronology. The flexibility of luminescence is a key complement to other chronometers such as radiocarbon or cosmogenic nuclides. Like all geochronologic techniques, context is necessary for interpreting and calculating luminescence results and this can be achieved by supplying our lab with associated trench logs, photos, and stratigraphic locations of sample sites if you choose to work with us (Taken from Gray et al, 2015 paper Guide to Luminescence Dating Techniques and their Application for Paleoseismic Research; Mahan and DeWitt, 2019, Principles and history of Luminescence Dating Chapter 1 in Handbook of Luminescence Dating AND Mahan et al, 2022 guide for interpretating and reporting luminescence dating results).
The USGS Luminescence Geochronology Lab is composed of myself, Harrison Gray, and Emma Krolczyk. We are an integral part of multi-disciplinary, multi-agency, and multi-institutional projects that provide chronologic control for Quaternary field studies in the continental United States. The growth of the laboratory is due to the science that our partnership can generate with many other science agencies, both Federal, state, and academic. Additional publications and projects can be viewed from USGS Luminescence Dating Laboratory and on Research Gate.
Professional Experience
2023 - present: Acting Deputy Center Director
2021 - present: TRIGA Reactor System Administrator and Science Advisor
2008 - present: Research Geologist
1987 - 2008: Geologist
Education and Certifications
1986: B.S., Geology, Adams State College
Affiliations and Memberships*
Geological Society of America
Friends of the Pleistocene
INQUA
Science and Products
Late Pleistocene and Holocene uplift history of Cyprus: implications for active tectonics along the southern margin of the Anatolian microplate
Geochronologic evidence for a possible MIS-11 emergent barrier/beach-ridge in southeastern Georgia, USA
Low footwall accelerations and variable surface rupture behavior on the Fort Sage Mountains fault, northeast California
Paleontology and geochronology of the Long Beach core sites and monitoring wells, Long Beach, California
Logs and data from trenches across and near the Green Valley Fault at the Mason Road site, Fairfield, Solano County, California, 2006-2009
The influence of upper-crust lithology on topographic development in the central Coast Ranges of California
Building on previous OSL dating techniques for gypsum: a case study from Salt Basin playa, New Mexico and Texas
Holocene dune formation at Ash Meadows National Wildlife Area, Nevada, USA
Basin-floor Lake Bonneville stratigraphic section as revealed in paleoseismic trenches at the Baileys Lake site, West Valley fault zone, Utah
Slip rate and slip magnitudes of past earthquakes along the Bogd left-lateral strike-slip fault (Mongolia)
A loess–paleosol record of climate and glacial history over the past two glacial–interglacial cycles (~ 150 ka), southern Jackson Hole, Wyoming
The angus mammoth: A decades-old scientific controversy resolved
Science and Products
Late Pleistocene and Holocene uplift history of Cyprus: implications for active tectonics along the southern margin of the Anatolian microplate
Geochronologic evidence for a possible MIS-11 emergent barrier/beach-ridge in southeastern Georgia, USA
Low footwall accelerations and variable surface rupture behavior on the Fort Sage Mountains fault, northeast California
Paleontology and geochronology of the Long Beach core sites and monitoring wells, Long Beach, California
Logs and data from trenches across and near the Green Valley Fault at the Mason Road site, Fairfield, Solano County, California, 2006-2009
The influence of upper-crust lithology on topographic development in the central Coast Ranges of California
Building on previous OSL dating techniques for gypsum: a case study from Salt Basin playa, New Mexico and Texas
Holocene dune formation at Ash Meadows National Wildlife Area, Nevada, USA
Basin-floor Lake Bonneville stratigraphic section as revealed in paleoseismic trenches at the Baileys Lake site, West Valley fault zone, Utah
Slip rate and slip magnitudes of past earthquakes along the Bogd left-lateral strike-slip fault (Mongolia)
A loess–paleosol record of climate and glacial history over the past two glacial–interglacial cycles (~ 150 ka), southern Jackson Hole, Wyoming
The angus mammoth: A decades-old scientific controversy resolved
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government