Paleogene Climate Conundrums
September's Shell London lecture, delivered by Tom Dunkley Jones (Imperial College London) at the Geological Society on 21 September 2011.
The Paleogene period represents two thirds of the time elapsed since the end Cretaceous mass extinction event. Dominated in its early stages by a continuation of late Mesozoic warm climates, the early Paleogene witnessed geologically short-lived transient warming events, or hyperthermals, which have been much studied as potential analogues of current carbon cycle, climate and biotic perturbations. Peak warmth - especially extreme high-latitude warmth - during the early Eocene climatic optimum (~50-52Ma) continues to pose a significant challenge to the climate modelling community, despite recent methodological advances in proxy temperature estimation that has largely resolved the "cool tropics" paradox. Gradual high-latitude and then global cooling through the middle to late Eocene culminated in the geologically rapid growth of the East Antarctic Ice Sheet, to around its modern extent, at the Eocene/Oligocene Boundary. This "one-cold pole" glaciated state then persisted to the end of the Paleogene and beyond.
The lecture aims to show how rapid climate events, specifically the Paleocene Eocene Thermal Maximum (PETM) - the largest of the Paleogene hyperthermals - and the Eocene/Oligocene transition are expressed in the geological record. Tom Dunkley Jones will present primary sedimentary, palaeontological and geochemical data from these intervals recovered from sections in Tanzania, Spain and from recent ocean drilling in the eastern Equatorial Pacific. This will include a whistle-stop tour of some truly astounding fossil discoveries from the micropalaeontological Lagerstätte of southern Tanzania, the amazing technological capabilities of the newly refurbished ocean drilling vessel the JOIDES Resolution and current attempts to reconcile climate model and proxy data reconstructions of PETM global warming.
Speaker
Tom Dunkley Jones (Imperial College London)
Biography
Tom Dunkley Jones is a Royal Society Dorothy Hodgkin Research Fellow within the Department of Earth Science and Engineering, Imperial College London. Having worked for a number of years as a consultant hydrogeologist, Tom returned to academia, undertaking PhD research at University College London into exceptionally-well preserved coccolithophore algae recovered in Paleogene sediments of coastal Tanzania. Tom has worked on these assemblages to understand the evolution, diversity and ecology of these marine phytoplankton through time and the inter-relationship with wider climatic and oceanographic change.
In 2009 he sailed as a nannofossil palaeontologist on Integrated Ocean Drilling Program Expedition 320 to the eastern Equatorial Pacific and in 2010 was awarded the Geological Society President's Award for gifted young geoscientists.
Sponsor
