Middle Miocene environmental and climatic evolution at the Wilkes Land margin, East Antarctica

• Main Authors: Sangiorgi, Francesca, Passchier, Sandra, Salzmann, Ulrich, Schouten, Stefan, Pross, Jorg, Bijl, Peter, Tauxe, Lisa, Bendle, James, Escutia, Carlotta, Brinkhuis, Henk
• Format: Conference Object
• Language: unknown
• Published: 2012
• Subjects: F800 Physical and Terrestrial Geographical and Environmental Sciences; Antarctic; East Antarctica; Wilkes Land; Antarc*; Antarctica; Sea ice; Tundra
• Online Access: https://nrl.northumbria.ac.uk/id/eprint/17923/

Integrated Ocean Drilling Program (IODP) Expedition 318 successfully drilled a Middle Miocene (~ 17 – 12.5 Ma) record from the Wilkes Land Margin at Site U1356A (63 °18.6138′S, 135 °59.9376′E), located at the transition between the continental rise and the abyssal plain at 4003 mbsl. We present a multiproxy palynological (dinoflagellate cyst, pollen and spores), sedimentological and organic geochemical (TEX86, MBT/CBT) study, which unravels the environmental and climate variability across the Miocene Climatic Optimum (MCO, ~17-15 Ma) and the Mid Miocene Climate Transition (MMCT). Several independent lines of evidence indeed suggest a relatively warm climate during the MCO. Dinocyst and pollen assemblage diversity at the MCO is unprecedented for a Neogene Antarctic record and indicates a temperate, sea ice-free marine environment, with woody sub-antarctic vegetation with elements of forest/shrub tundra and peat lands along the coast. These results are further confirmed by relatively warm TEX86-derived Sea Surface Temperatures and mild MBT-derived continental temperatures, and by the absence of glacially derived deposits and very few ice-rafted clasts. A generally colder but highly dynamic environment is suggested for the interval 15-12.5 Ma.