Theodore R. Them II

Assistant Professor

Education

Shippensburg University of Pennsylvania
B.S. Geoenvironmental Studies, 2008

Virginia Tech
Ph.D. Geosciences, 2016

Research Interests

I am interested in reconstructing environmental change across multiple timescales and geologic events throughout Earth’s history. I focus much of my attention on ancient intervals associated with global environmental deterioration and mass extinction, but am also interested in modern environments. I direct the Geochemistry of Ancient and Modern Environmental Systems (GAMES) Laboratory. I also serve on the editorial board of Geology. 

Laboratory Website

Courses Taught

Honors and Awards

2024-2025: Fulbright U.S. Scholar, Durham University, United Kingdom.

2023-2028: Collaborative Research: How did Terrestrial Ecosystems Rebuild Following the Cretaceous/Paleogene Mass Extinction, U.S. National Science Foundation (EAR-FRES-EPSCoR-2317668), Co-I ($287,349 out of $2,993,795). 

Publications

Paine, A.R., Fendley, I.M., Frieling, J., Mather, T.A., Lacey, J.H., Pyle, D.M., Robinson, S.A., Wagner, B., Them, T.R. II, Panagiotopoulos, K., 2024, Mercury records covering the past 90000 years from lakes Prespa and Ohrid, SE Europe. Biogeosciences, 531 – 556.

Yuan, W., Liu, M., Chen, D., Xing, Y.-W., Spicer, R.A., Chen, J., Them II, T.R., Wang, X., Li, S., Guo, C., Zhang, G., Zhang, L., Zhang, H., Feng, X., 2023, Mercury isotopes show vascular plants colonized land extensively by the early Silurian, Science Advances, 9, eade9510. 

Kozik, N.P., Young, S.A., Newby, S.M., Liu, M., Chen, D., Hammarlund, E.U., Bond, D.P.G., Them II, T.R., Owens, J.D., 2022, Rapid marine oxygen variability: driver of the Late Ordovician mass extinction, Science Advances, 8, eabn8345. 

Them II, T.R., Owens, J.D., Marroquín, S.M., Caruthers, A.H., Trabucho Alexandre, J.P., Gill, B.C., 2022, Reduced marine molybdenum inventory related to enhanced organic carbon burial and an expansion of reducing environments in the Toarcian (Early Jurassic) oceans, AGU Advances, 3, e2022AV000671. 

Veenma, J.P., McCabe, K., Caruthers, A.H., Aberhan, M., Golding, M., Marroquín, S.M., Owens, J.D., Them II, T.R., Gill, B.C., Trabucho Alexandre, J.P., 2022, The Glass Ramp of Wrangellia: Late Triassic to Early Jurassic Outer Ramp Environments of the McCarthy Formation, Alaska, Journal of Sedimentary Research, 92, 896 – 919. 

Liu, W., Liu, M., Yang, T., Liu, X., Them II, T.R., Wang, K., Bian, C., Meng, Q., Li, Y., Zeng, X., Zhao, W., 2022, Organic matter accumulations in the Santonian-Campanian (Upper Cretaceous) lacustrine Nenjiang shale (K2n) in the Songliao Basin, NE China: terrestrial response to OAE3? International Journal of Coal Geology, 260, 104069. 

Caruthers, A.H., Marroquín, S.M., Gröcke, D.R., Golding, M., Aberhan, M., Them II, T.R., Veenma, J.P., Owens, J.D., McRoberts, C.A., Friedman, R.M., Trop, J.M. Szúcs, D., Pálfy, J., Rioux, M., Trabucho Alexandre, J.P., Gill, B.C., 2022, New evidence for a long Rhaetian from a Panthalassan section (Wrangell Mountains, Alaska), and regional differences in carbon cycle perturbations at the Triassic-Jurassic transition, Earth and Planetary Science Letters, 577, 117262. 

Bowman, C.N., Them II, T.R., Knight, M.D., Kaljo, D., Eriksson, M.E., Hints, O., Martma, T., Owens, J.D., Young, S.A., 2021, A multi-proxy approach to constrain locally reducing conditions in the Baltic Basin during the late Silurian (Ludfordian) Lau carbon isotope excursion, Palaeogeography Palaeoclimatology Palaeoecology, 581, 110624. 

Liu, M., Ji, C., Hu., H., Xia, G., Yi. H., Them II, T.R., Sun, P., Chen, D., 2021, Variations in microbial ecology during the Toarcian Oceanic Anoxic Event (Early Jurassic) in the Qiangtang Basin, Tibet: evidence from biomarker and carbon isotopes, Palaeogeography Palaeoclimatology Palaeoecology, 580, 110626. 

Shen, J., Feng, Q., Algeo, T., Liu, J., Zhou, C., Wei, W., Liu, J., Them II, T.R., Gill, B.C., Chen, J., 2020, Sedimentary host phases of mercury (Hg) and implications for use of Hg as a volcanic proxy, Earth and Planetary Science Letters, 543, 116333. 

Press & Media

Earlier evolution of land plants revealed by mercury isotopes 

CofC news article on trace metal inventory of Early Jurassic oceans. Also see Editors' Highlights in Eos. 

Variable marine oxygen levels across first “big 5” mass extinction