Dr Eleanor Maddison
I am a research associate based jointly in the Department of Geography and the Institute of Hazard, Risk and Resilience. My expertise lies in reconstructing periods of rapid climate change using micropalaeontology, geochemistry and sedimentology. My current research is focussed upon reconstructing Neoglacial cooling using chironomids. This research falls within Working Package 1 of the interdisciplinary Leverhulme Trust funded project Tipping Points (http://www.dur.ac.uk/ihrr/tippingpoints/).
Tipping Points: Rapid Neoglacial transitions in the North Atlantic
The cause of mid-Holocene rapid cooling, about 4-6 ka, has puzzled researchers for some time. In order to ascertain the nature and origins of this event I am using the remains of chironomids preserved in lake sediments to construct temperature records of this period of cooling. Chironomids are two-winged flies, which are often referred to as non-biting midges. The aquatic chironomid larvae are abundant in lake sediments and are well preserved due to their chitinized head capsules. These factors, along with their virtually instantaneous response to temperature change (due to their ability to fly and their short lifecycles) make them an ideal tool for reconstructing past climate. In order to infer temperature records from fossil chironomid assemblages, I will be developing modern chironomid-temperature calibration datasets. By quantifying modern temperature ranges of each chironomid taxon, I will derive estimates of past temperatures during the period of rapid cooling.
Other members of Working Package 1: Professor Antony Long (Department of Geography), Professor Brian Huntley (School of Biological and Biomedical Sciences) and Dr Helen Ranner (School of Biological and Biomedical Sciences).
Causes and consequences of global cooling in the mid-Miocene
Postdoctoral Research Scientist, Open University, 2006-2009 (NERC-funded).
Working with: Dr Angela Coe and Dr Antony Cohen.
An investigation of mid-Miocene cooling was made by conducting high-resolution logging and analysis of organic-rich marine sediments (Monterey Formation, California). Fourier analysis of organic-rich mudrock facies revealed regular depositional cycles through this period of rapid cooling. These cycles and new biostratigraphic ages were correlated to the Laskar orbital solution to produce a new astronomical timescale (~16-13 Ma). Trends in our high-resolution carbon isotope record are comparable to distinctive carbon maxima events in deep sea sediment sections. Large carbon isotope shifts in the record may relate to either methane hydrate release or to changes in the organic carbon sediment source. Foraminiferal oxygen isotopes indicate that bottom water temperatures fluctuated on the continental margin during this global cooling event.
High-resolution analysis of Antarctic Quaternary diatom-rich laminated sediments
PhD, Cardiff University, 2002-2006 (NERC-funded).
Supervisors: Dr Jennifer Pike (Cardiff University) and Dr Amy Leventer (Colgate University).
The seasonality of Late Quaternary Antarctic climate and sea ice conditions were investigated by examining laminated diatom-rich sediments from the Antarctic Peninsula (Palmer Deep) and East Antarctica (Mertz Ninnis Trough and Dumont D’Urville Trough). To do this a quantitative and qualitative high-resolution approach was employed to analyse diatom assemblages. The deposition of diatom-rich laminae were controlled by seasonal changes in sea ice conditions, nutrient levels and water column conditions on the continental shelf. Variations in lamina and sub-lamina were caused by changes in continental shelf oceanographic conditions such as upwelling water fluctuations and the presence of a palaeo-polynya.
- Quaternary palaeoenvironments
- Palaeoclimate reconstruction
Journal papers: academic
- Maddison, EJ, Pike, J & Dunbar, R Seasonally-laminated diatom-rich sediments from Dumont d’Urville Trough, East Antarctic Margin: Late Holocene Neoglacial sea-ice conditions. The Holocene. 2012;22:857-875.
- Pike, J., Crosta, X., Maddison, E. J., Stickley, C. E., Denis, D., Barbara, L. & Renssen, H. Observations on the relationship between the Antarctic coastal diatoms Thalassiosira antarctica Comber and Porosira glacialis (Grunow) Jorgensen and sea ice concentrations during the late Quaternary. Marine Micropaleontology. 2009;73:14-25.
- Leventer, A., Domack, E., Dunbar, R., Pike, J., Stickley, C., Maddison, E., Brachfeld, S., Manley, P., & McClennen, C., East Antarctic Margin marine sediment record of deglaciation. GSA Today. 2006;16:4-10.
- Maddison, E. J., Pike, J., Leventer, A., Dunbar, R., Brachfeld, S., Domack, E. W., Manley, P. & McClennen, C. Post-glacial seasonal diatom record of the Mertz Glacier Polynya, East Antarctica. Marine Micropaleontology. 2006;60:66-88.
- Maddison, E. J., Pike, J., Leventer, A. & Domack, E. W. Deglacial seasonal and sub-seasonal diatom record from Palmer Deep, Antarctica. Journal of Quaternary Science. 2005;20:435-446.