ACE Oligocene-Miocene Subcommittee

Oligocene-Miocene ACE subcommittee

Rationale:

The Oligocene-Miocene boundary marks a significant transition in the development of the Antarctic cryosphere, where small dynamic ice sheets of the late Oligocene rapidly expanded to continental scale in the early Miocene. Sediment cores recovered in Western Ross Sea indicate orbital modulation of the ice sheet during the transition. It is argued that the transition occurred as a consequence of a unique set-up of orbital parameters during an interval of declining CO 2 that led to a prolonged period of cold summer orbits, during which time a large ice sheet established. The main functions of the committee are to develop and implement environmental research investigating:

The Eocene-Oligocene climate transition and earliest Oligocene glaciation.
The nature and timing of Oligocene ice sheet variability.
The response/role of Antarctica in possible Late Oligocene global warming.
Transient cooling events including the Mi1 glaciation.
The nature of early Miocene ice sheet variability.
The Mid-Miocene Climate Optimum (MCO) and it’s signature in Antarctica.
Mid-Late Miocene cooling and stepped ice volume increase (working jointly with the Miocene-Pliocene sub-committee chaired by Dr Alan Haywood).

Focus:

Emphasis will be placed on understanding Antarctica’s role in (and response to) fundamental climate transitions and ephemeral events through the late Paleogene and early Neogene. This will be accomplished through the synthesis of newly acquired data from Antarctic field investigations with data from ongoing deep sea drilling expeditions and sequence stratigraphic reconstructions of eustasy. These synthesized data will be integrated into numerical modelling studies to 1) test data-driven hypotheses, 2) explore the envelope of climate-cryosphere behavior in response to specific forcings, and 3) to explore possible mechanisms and feedbacks responsible for the dramatic Antarctic and global environmental changes recognized in Paleogene and Neogene proxy climate records.

Committee Membership:

Robert DeConto (chair) USA; David Pollard (proposed) Penn State University, USA; Matthew Huber (proposed), USA; Steve Pekar, USA; David Harwood (proposed), USA; Catherine Stickley (proposed), UK; Katarina Billups, USA. Members from other nations are TBA.