|
Original Article |
1 1Department of Geology, University College Cork, Cork, Ireland
2 2Department of Paleobiology MRC 121, Smithsonian Institution, 10th and Constitution Avenue NW, Washington, DC 20560-0121, USA
3 3Present address: School of Geography, Earth and Environmental Sciences, The University of Birmingham, Birmingham B15 2TT, UK (e-mail: g.j.harrington@bham.ac.uk)
4 4British Geological Survey, Keyworth, Nottingham NG12 5GG, UK
5 5Department of Earth Sciences, University of California, Santa Cruz, CA 95064, USA
The Initial Eocene Thermal Maximum (IETM) at c. 55 Ma represents a period of rapid global warming that lasted less than 200 ka. The response of vegetation to such an event, and particularly warm-adapted highly diverse vegetation types, is poorly understood. Using pollen floral, clay mineral and stable carbon isotope analyses of sediments from the upper Tuscahoma Formation on the eastern US Gulf Coast (eastern Mississippi and western Alabama), we document paratropical floral changes across the PalaeoceneEocene boundary from the Wahalak #2 and lower Harrell cores. Data indicate strong changes in the abundance of kaolinite that correlate with changes in relative abundance of native pollen taxa. There is no evidence for a transient, extra-tropical flora on the US Gulf Coast that may characterize the IETM. Immigration and extinction are not associated with this event. Instead, Early Eocene plant immigration occurs in pulses and therefore is not associated directly with climate change during the IETM. The two cores share the same regional species pool but compositional differences are stronger between cores than they are either through changes in environment, increased soil erosion or chemical weathering, or through the introduction of non-native plants. Our data suggest that vegetation change across the PalaeoceneEocene boundary is not a single event but rather a sequence of cascading events.
Key Words: lower Eocene US Gulf Coast 13C kaolinite palynology vegetation
This article has been cited by other articles:
![]() |
P. D. Gingerich, K. D. Rose, and T. Smith Oldest North American primate PNAS, 2008; 105: E30 - E30. [Full Text] [PDF] |
||||
![]() |
G. J. Harrington and C. A. Jaramillo Paratropical floral extinction in the Late Palaeocene-Early Eocene Journal of the Geological Society, 2007; 164: 323 - 332. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. L. Wing, G. J. Harrington, F. A. Smith, J. I. Bloch, D. M. Boyer, and K. H. Freeman Transient Floral Change and Rapid Global Warming at the Paleocene-Eocene Boundary Science, 2005; 310: 993 - 996. [Abstract] [Full Text] [PDF] |
||||