Plant community response to the PETM


Greenhouse climates in deep-time provide fascinating insights into how animal and plant communities responded to warming global temperatures. A major perturbation of the climate occurred at the Paleocene-Eocene boundary (c.56 million years ago) in what is termed the Paleocene-Eocene Thermal Maximum (PETM). 

Coincident with global warming was a massive release of light carbon into the atmosphere that fueled global warming leading to rises in temperature from the deep-oceans through to high-latitude landmasses by c. 6 Celsius. The PETM was transient – the total duration was less than 200,000 years but peak warmth marks only a part of this event. 

My research uses the PETM as a model system for exploring how plants respond to warming and addresses the consequences of prolonged climate change. I am a micropalaeontologist and use the fossil record of pollen and spores as a proxy for vegetation in deep-time. 

One project I am actively involved in is the Bighorn Basin Coring Project (BBCP) that represents a consortium of several leading US research institutions to investigate the PETM from the best preserved sections in the Bighorn Basin, Wyoming, USA. 

BBCP polecat

Today, this area is classed as dry desert (figure 1) but in the late Paleocene and early Eocene this whole area was a floodplain environment covered by forests similar to those found today in south-east China and eastern USA. 

The Bighorn Basin has a spectacular record of mammal, reptile, plant and pollen records spanning over 5 million years preserved in fossil soils, swamps, ponds and channel fills. The BBCP involved taking three cores from different part of the Bighorn Basin and our research into the pollen record represents the best terrestrial record of plant change through this important event in geological history. 

Primarily my research and field areas are centred on the USA. My areas include Wyoming, Colorado, North Dakota, Mississippi, Alabama, Louisiana, and Texas. I also undertake industrial work from the Gulf of Mexico (GoM) from wells that penetrate Paleocene-Eocene strata in the deep-waters in the GoM.

Member of staff involved

  • Guy Harrington

Former researchers 

  • Phillip Jardine
  • Jirina Dašková

Project funding

  • EU Framework 7
  • National Science Foundation (NSF)


Sluijs, A.,van Roij, L., Harrington, G.J., Schouten, S., Sessa, J.A., Schneider, L.J., Reichart, G.-J., & Slomp, C.P. (2013). Intense warming, ocean anoxia and sea level rise during the Paleocene/Eocene Thermal  Maximum along the US margin of the Gulf of Mexico. Climates of the Past Discussion 9:6459-6494, doi:10.5194/cpd-9-6459-2013. 

Clyde, W.C. et al. (BBCP Science Team) (2013) Bighorn Basin Coring Project (BBCP): A continental perspecive on Early Paleogene Hyperthermals. Scientific Drilling.16:21-31. doi:10.5194/sd-16-21-2013. 

Jardine, P.E., Harrington, G.J. & Stidham, T, 2012. Regional-scale spatial heterogeneity in the Late Paleocene paratropical forests of the U.S. Gulf Coast. Paleobiology. 38:15-39.

Jardine, P.E. & Harrington, G.J. 2008. The Red Hills Mine flora: a diverse swamp palynoflora from  the Late Paleocene of Mississippi. U.S.A. Palynology v. 32:183-204. 

Harrington, G.J. 2008. Palaeocene-Eocene paratropical swamp palynofloras from Alabama and Mississippi, USA. Palaeontology v. 51: 611-622. 

Clechenko, E.R., Kelly, D.C., Harrington, G.J. & Stiles, C.A. 2007. Terrestrial records of a regional weathering pattern at the Paleocene-Eocene boundary in the Williston Basin of North Dakota. GSA Bulletin v. 119: 428-442. 

Harrington, G.J. & Jaramillo, C.A. 2007. Paratropical floral extinction in the Late Palaeocene–Early Eocene. Journal of the Geological Society of London v. 164: 323-332. 

Wing, S.L., Harrington, G.J., Smith, F.A., Bloch, J.I, Boyer, D.M. & Freeman, K.H. 2005. Transient floral change and rapid global warming at the Paleocene-Eocene boundary. Science v. 310: 993–996. 

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