Climate Research and Development

Eocene Hyperthermals

The Marlboro Clay (Early Eocene) at the shallow, river-influenced Mattawoman Creek-Billingsley Road site is composed of a stacked succession of hundreds of muddy turbidites with numerous very fine laminations. These sediments record both marine and terrestrial responses to the PETM.
The Marlboro Clay (Early Eocene) at the shallow, river-influenced Mattawoman Creek-Billingsley Road site is composed of a stacked succession of hundreds of muddy turbidites with numerous very fine laminations. These sediments record both marine and terrestrial responses to the PETM.

The Late Paleocene and Early Eocene were punctuated by a series of sudden and extreme global warming events (~55.5, 53.5 and 52.5 Ma) that were triggered by massive releases of carbon into the atmosphere. While the mid-Pliocene warm period provides an analog for modern CO2 concentrations, Eocene hyperthermals provide analogs for the extremely rapid rates of atmospheric carbon increase that we are currently witnessing. The Paleocene-Eocene Thermal Maximum (PETM) is the most intensively studied of the Eocene hyperthermals. During the PETM, global temperatures rose by ~5°C (~9°F), ocean acidification was widespread, floral and faunal communities were severely disrupted, and benthic foraminifera suffered a mass extinction in the deep sea due to changing oceanic circulation and a disrupted carbon cycle. Subsequent successive and progressively less extreme hyperthermals followed. This project examines Eocene hyperthermals in terms of the response of critical ecosystems in shallow marine environments using sediment cores collected along the US mid-Atlantic coast. While more recent warm intervals better represent modern or near future climate, Eocene hyperthermals most closely resemble the modern in terms of the rate of change of atmospheric CO2 and temperature. It is here that we will find similarities in the response of marine ecosystems to abrupt changes in climate such as are projected due to anthropogenic greenhouse gas release.

Our main objectives are to: 1) investigate biotic patterns of both marine and terrestrial flora and fauna surrounding Eocene hyperthermals by characterizing extinction and recovery patterns through statistical analyses of assemblage changes; 2) document the impacts on marine ecosystems along the shallow coastal region from Georgia to Maryland, determining the effect of water depth and/or ocean acidity, depositional environment, fresh water and sediment influx; and 3) correlate the changes in shallow environments to those in the deep sea.

Investigations of biotic patterns of marine and terrestrial flora and fauna are attained through quantitative micropaleontological analyses of sediment samples. Changes in fossil distribution patterns through time trace changes in environmental conditions and the biotic response to them. Geochemical analyses of stable isotopes and trace metals in foraminifer tests (shells) aid paleothermometry and paleosalinity reconstructions. In addition, sedimentological analysis of clay content and magnetic susceptibility reveal relationships between changing environment, sedimentation rates, and lysocline (depth at which rate of dissolution of calcite increases dramatically) shoaling.

Why is this research important?

Eocene hyperthermals are of great importance to climate science as they resemble modern climate change in their accelerated rate of change of atmospheric carbon dioxide and temperature and yet remain poorly understood. Our hyperthermal research will document the response of shallow marine ecosystems to brief intervals of elevated CO2, warmer temperatures and enhanced hydrologic cycles relative to background conditions. Our research will inform the scientific community, policy-makers and the general public by providing products that reconstruct the shallow marine environments across the US mid-Atlantic coastline within single hyperthermal events as well as among several different intervals of abrupt climate change. These studies will provide insights on how biological systems adapted to these changes temporally and spatially. Our paleodata can assist in evaluations of the potential consequences of future global change and provide assessments of the abilities of climate models to simulate past changes.

Project Lead:
Marci Robinson, Eastern Geology and Paleoclimate Science Center
Project Team:
Jean Self-Trail, Dave Powars, Ellen Seefelt, Tom Sheehan, Whittney Spivey

7 publications matching the specified parameters were found.

Sleeter, B.M., Wood, N.J., Soulard, C.E. and Wilson, T.S., 2017, Projecting community changes in hazard exposure to support long-term risk reduction: A case study of tsunami hazards in the US Pacific Northwest, International Journal of Disaster Risk Reduction, v. 22, p. 10-22.
Available at: http://dx.doi.org/10.1016/j.ijdrr.2017.02.015

Bralower, T.J. and Self-Trail, J.M., 2016, Nannoplankton malformation during the Paleocene-Eocene Thermal Maximum and its paleoecological and paleoceanographic significance, Paleoceanography, v. 31, p. 1423-1439.
Available at: https://doi.org/10.1002/2016PA002980

Swezey, C.S., Fitzwater, B.A., Whittecar, G.R., Mahan, S.A., Garrity, C.P., González, W.B.A. and Dobbs, K.M., 2016, The Carolina Sandhills: Quaternary eolian sand sheets and dunes along the updip margin of the Atlantic Coastal Plain province, southeastern United States, Quaternary Research, v. 86, p. 271-286.
Available at: https://doi.org/10.1016/j.yqres.2016.08.007

Markewich, H.W., Litwin, R.J., Wysocki, D.A., and Pavich, M.J., 2015, Synthesis on Quaternary aeolian research in the unglaciated eastern United States, Aeolian Research, v. 17, p. 139-191.
Available at: http://dx.doi.org/10.1016/j.aeolia.2015.01.011

Seefelt, E.L., Self-Trail, J.M., and Schultz, A.P., 2015, Comparison of three preservation techniques for slowing dissolution of calcareous nannofossils in organic rich sediments: Stratigraphy, v. 61, p. 149-164.
Available at: https://pubs.er.usgs.gov/publication/70157064

Robinson, M.M., Self-Trail, J.M., Wandless, G.A., and Willard, D.A., 2014, A Paleocene Pre-Onset isotope excursion recorded in the shallow marine environment of Southern Maryland (USA): Climatic and Biotic Events of the Paleogene, Ferrara, Italy, July 1-6, 2014, Rendiconti Online, Societa Geologica Italiana, v. 31, p. 185-186.

Self-Trail, J.M., Robinson, M.M., Willard, D.A., Bralower, T.J., Edwards, L.E., Powars, D.S., Freeman, K., and Wandless, G.A., 2014, Comparison between two middle to outer neritic PETM sections, in South Dover Bridge and Mattawoman Creek Billingsley Road cores, Mid-Atlantic Coastal Plain, USA: Climatic and Biotic Events of the Paleogene 2014, Ferrara, Italy, July 1-6, Rendiconti Online, Societa Geologica Italiana, v. 31, p. 195-196.