Back row, left to right:  Undergraduates Researcher Jordan Tyo, Katie Seguin, Zoey Plonka, PI Dr. Nathan Sheldon, Graduate Student Rebekah Stein. Front row, left to right: Graduate student Melanie Shadix, Undergraduate Researcher Fiona Fox, Graduate Student Rebecca Dzombak, Undergraduate Researcher Sonya Vogel. Missing from photo: Undergraduate researchers Bianca Gallina, Amelia Jelic.


Current Research Group


Dr. Nathan Sheldon – Principal Investigator

Ph.D.: University of Oregon, 2003

BA: Carleton College, 1999

Current Research Field Areas: Montana, Wyoming, Spain

Google Scholar ProfileResearchGateInstagramDeep BluePublons


Graduate Students and Post-docs

Becca Dzombak, Ph.D Candidate

Research: Becca is interested in the co-evolution of terrestrial landscapes, the atmosphere, and the biosphere, with a focus on nutrient cycles (Fe, P) during key transitions in Earth’s history. She uses the biogeochemistry of soils (modern and ancient) to explore questions like climatic controls on soil nutrients, the potential for microbial nutrient cycling in the past, and connections between terrestrial and marine productivity.

Expected Completion: Spring 2021

Becca’s Personal Website ResearchGate – TwitterInstagram


Rebekah Stein, Ph.D Candidate, Co-Advised with Dr. Selena Smith

Research: Bekah is currently looking at the relationship between conifer carbon isotope fractionation and atmospheric CO2 over the recent past. Her general research interests are biogeochemical cycles, stable isotopes, and modern and paleoclimate in recorded by terrestrial systems.

Expected Completion: Spring 2021

Bekah’s Personal Website – ResearchGateTwitterInstagram

Melanie Shadix, M.S. Student

Research: Melanie is interested in how climate change creates vulnerabilities for military bases
through its effect on plants in arctic regions.

Expected Completion: February 2021


Current Research Group – Undergraduates

Sonya Vogel (junior): Seasonal nutrient cycling in a Michigan wetland

Catherine Seguin (senior): Phosphorus cycling in biological soil crusts

Bianca Gallina (senior): Biogeochemistry in modern and fossilized soils.

Aliah Wright-Johnson, Research: Isotope biogeochemical signals in Cupressaceae, evolution + carbon isotopes

Zoey Plonka, Research: Elevation and isotope fractionation in plants.

Amelia Jelic, Research: Nutrient cycling in Middle Island Sinkhole.

Maggie Hammond, Research:  Nutrients in the Middle Island Sinkhole.

Jordan Tyo (junior): Paleoclimates and paleoenvironments

Group Alumni:

Kathryn Rico, UM PhD (Google Scholar)

Research: Biogeochemistry (nutrient and trace metal cycling) of aquatic systems for a better understanding of Proterozoic ocean chemistry

Completion: May 2019

Current Position: Wares Post-Doctoral Fellow at McGill University


Allyson Tessin, UM PhD (Google Scholar)

Research: “Organic carbon burial under greenhouse climate conditions: The regional expression of the Late Cretaceous Oceanic Anoxic Event 3 within the Western Interior Seaway”

Completion: Spring 2016

Current Position: Asst. Professor, University of Southern Mississippi


Timothy Gallagher, UM PhD (Google Scholar

Research: “Refining pedogenic carbonate proxies for improved reconstructions of terrestrial environmental conditions”

Completion: Summer 2016

Current Position: Post-Doctoral Fellow at the University of Texas at Austin


Chelsea Mervenne, UM M.Sc.

Research: Stable Isotope Ecology in Conifers

Completion: Spring 2016

Current Position: Director of Environmental Programs, Corazon Latino, Inc.


Ethan Hyland, UM PhD (Google Scholar)

Research: “Multiproxy Terrestrial Records of Climatic and Ecological Change During the Early Eocene Climatic Optimum”

Completion: Spring 2014

Current Position: Assistant Professor at North Carolina State University


Lauren Kinsman-Costello, M-Cubed Postdoctoral Fellow (Google Scholar)

Research: Biogeochemistry of the Middle Island Sinkhole, Lake Huron

Completion: December 2014

Current Position: Research Assistant Professor, Kent State University


Jennifer Cotton, UM PhD (Google Scholar)

Research: “Using Soils to Constrain Past and Future Terrestrial Climate Change”

Completion: Spring 2013

Current Position: Assistant Professor at California State University Northridge


Jessica Hamer, RHUL PhD

Research: “Interpreting Cenozoic Floodplains: A Paleopedological and Ichnological Prespective”

Completion: Fall 2009

Current Position: UK Physics Trust


Ria Mitchell, RHUL PhD (Google Scholar)

Research: Weathering and Paleosol Formation of the Keweenawan Rift

Completion: Fall 2010

Current Position: Research Scientist in Microanalysis and Micro imaging at Swansea University (UK)


Lauren Miller, UM M.S.

Research: Reconstructing Eocene Paleovegetation with Phytoliths

Completion: Summer 2010


Michael Hren, Turner Post-Doctoral Fellow

Research: Clumped Isotopes, Organic Geochemistry, Paleohydrology, Paleoclimate

Completion: 2012

Current Position: Assistant Professor at the University of Connecticut


Meredith Dennis, UM Masters

Research: Paleosol Stable Isotopes, Phytoliths

Completion: Spring 2012

Current Position: Biologist at Zion National Park


Undergraduate Alumni:

Samantha Reasons, 2017-2018, University of Michigan

Charlotte Connop, 2014-2018, University of Michigan

Julia Derringer, 2016-2017, University of Michigan

Clarissa Crist, 2015-2017, Eastern Michigan University

Hu Chien Tan, 2015-2016, University of Michigan

Becca Dzombak, 2015-2016, University of Michigan

Hayley Knouff, 2014-2015, University of Michigan

Danielle Boshers, 2014-2015, University of Michigan

Hannah Sherman, 2014, University of Michigan

Kori Johnson-Lane, 2014, University of Michigan

Sara Leon, 2013-2017, University of Michigan

Steven Duric, 2013, University of Michigan

Chelsea Mervenne, 2013, University of Michigan

Kathryn Gallagher, 2013, University of Michigan

Stephanie Chen, 2013, University of Michigan

Christie Wilkins, 2012, University of Michigan

Bryana Boos, 2012, University of Michigan

Carli Balogh, 2012-2014, University of Michigan

Carla Valdes, 2012-2013 University of Michigan

Brigid Lynch, 2011-2012, University of Michigan

Tess Nugent, 2011-2013, University of Michigan

Sul Gi Ye Park, 2010-2011, University of Michigan

Stephanie Chen, 2009-2013, University of Michigan

Meredith Dennis, BA, PitE, 2010-2011, University of Michigan

Bryana Boos, 2010-2012, University of Michigan

Christie Wilkins, 2010-2012, University of Michigan

Yang Sheng, 2009-2010, University of Michigan

Caroline Kreafle, BA, PitE, 2009 (assisted), University of Michigan

Corinne Lund, 2008, University of Michigan

Holly Reay, 2008, Royal Holloway, University of London

Paul Gabraiel, 2007, Royal Holloway, University of London

Katherine Pomeroy, 2007, Royal Holloway, University of London

Alexander Twiney, 2007, Royal Holloway, University of London

Ria Mitchell, 2006, Royal Holloway, University of London