d.muller@usyd.edu.au
 

Currently a major Ocean Drilling Program (ODP) campaign south of Australia is being carried out, comprising nine drilling legs.  We propose to create a tectonic and paleogeographic framework for interpreting, modelling and synthesising these data. A joint analysis of Arctic and Antarctic regions will bring together a group of researchers from the Universities of Ottawa/Canada, California at San Diego/USA and Sydney to integrate data and models for the evolution of polar ocean basins and margins.  The project will strengthen our ties with centres of excellence in polar geoscience and help to maximise the return for Australia's investment in ODP.
 

Motivation

    Currently, the most comprehensive ocean drilling campaign in history south of Australia and around Antarctica is being carried out, comprising drilling nine legs.  They include drilling the Ninetyeast Ridge (179) , the Great Australian Bight (182), the South Tasman Rise (189), the Campbell Plateau (181), the Australian-Antarctic Discordance (187), Prydz Bay (188), the Kerguelen Plateau (183), Agulas Ridge/Meteor Rise (177) and the Antarctic Peninsula continental margin (178) (Figure 1).  The principal investigator of this proposal, Müller, has just returned from 9 weeks at sea, participating in ODP Leg 183, which drilled the Kerguelen Plateau, a large igneous province close to Australia’s only active volcanoes, Heard and McDonald islands.  The data collected on these cruises have the potential to vastly improve our understanding of the paleoceanography and paleoclimate, causes and effects of sea-level change, history of glaciation, and the deformation of the Earth’s crust in the southern hemisphere.
    However, major advances in our understanding of the link between deep Earth processes, paleogeography and the environment will require a synthesis of all relevant ODP data around Antarctica.  Such a synthesis will depend on accurate paleogeographic maps, which depict the distribution of landmasses and oceans and the gradual opening of ocean basins and gateways through time.  Recently, a large amount of new ship and satellite data have become available that allow us to create paleogeoraphic reconstructions in much greater detail than before.
    In view of the extensive current ocean drilling activity south of Australia and on the Antarctic margins, it is timely to utilise these data and the concepts, technologies, data bases and expertise developed for plate kinematics in all polar areas to create a revised paleogeographic framework through time.  To achieve this, we propose to bring together a group from the University of Ottawa/Geological Survey of Canada (GSC) and from the University of California at San Diego/Scripps Institute of Oceanography (SIO) to build upon a software system for database management, gridded data analysis and conceptual models developed for Arctic plate reconstructions at the GSC, and upon a large geophysical ship data base and data analysis expertise gathered at SIO, one of the top marine research centers in the world.
 

Detailed objectives:

1) Provide a tectonic framework for ODP drilling south of Australia, with emphasis on:

• reconstructions of relative and absolute plate motions
• changing plate boundary configurations through time
• the timing of the opening of oceanic gateways
• the role of large igneous provinces in obstructing oceanic gateways
• the role of microplate formation

2) Improve our understanding of the tectonic evolution of polar continental margins, in terms of:

• the timing of margin formation
• passive margin tectonic segmentation and the role of propagating rifts
• volcanism during continental breakup

Publications:

Gaina, C., Müller, R.D, Cande, S.C., 2000, Absolute plate motion, mantle flow and volcanism at the boundary between the Pacific
and Indian Ocean mantle domains since 90 Ma, American Geophysical Union Monograph, The History and Dynamics of Global
Plate Motions, in press

Gurnis, M., Moresi, L., and Müller, R.D, 2000, Models of mantle convection incorporating plate tectonics: The Australian Region
since the Cretaceous, American Geophysical Union Monograph, The History and Dynamics of Global Plate Motions, in press.

Gaina, C., Müller, R.D, Cande, S.C., 2000, Absolute plate motion, mantle flow and volcanism at the boundary between the Pacific
and Indian Ocean mantle domains since 90 Ma, American Geophysical Union Monograph, The History and Dynamics of Global
Plate Motions, in press

Müller, R.D., Gaina, C., and Clarke, S., Seafloor spreading around Australia, 2000, In: Billion-year earth history of Australia
and neighbours in Gondwanaland, ed. J. Veevers.

Frey, F.A., Coggin, M.F., Wallace, P.J., Weis, D., Zhao, X., Wise, S.W., Waehnert, V., Teagle, D.A.H., Sacocia, P.J., Reusch,
D.N., Pringle, M.S., Nicolaysen, K.E., Neal, C.R., Müller, R.D, Moore, C.L., Mahoney, J.J., Keszthelyi, L., Inokuchi, H., Duncan,
R.A., Delius, H., Damuth, J.E., Damasceno, D., Coxall, H.K., Borre, M.K., Boehm, F., Barling, J., Arndt, N.T., and Antretter, M.,
2000, Origin and evolution of a submarine large igneous province:  the Kerguelen Plateau and Broken Ridge, southern Indian Ocean,
Earth and Planetary Science Letters, 176, 73-89.

Cande, S.C., Stock, J.M., Müller, R.D, Ishihara, T., 2000, Cenozoic motion between East and West Antarctica, Nature, 404,
145-150.