(a) Abstract
The Australian Plate has undergone major changes in plate boundary geometry and relative plate velocities since the breakup of Gondwanaland. We illustrate the history of seafloor spreading around Australia by reconstructing gridded ocean floor ages and plate boundary configurations in a fixed Australian reference frame. In the Argo Abyssal Plain, seafloor spreading started at M25 dated as 154.3 Ma Late Jurassic (Oxfordian). The onset of seafloor spreading west of Australia at ~136 Ma marks the breakup between Greater India and Australia. Roughly at the same time, long-lived subduction east of Australia ceased, probably due to subduction of the Phoenix-Pacific spreading ridge, changing this plate boundary to a transform margin. … Read more…
Prof Dietmar Müller
Group Coordinator
Phone: +61 2 9351 4255
Fax: +61 2 9351 3644
School of Geosciences
The University of Sydney
Sydney, NSW 2006
Australia
View Dietmar's Sydney Uni page
See below for EarthByte content related to Dietmar.
Numerical Modeling of Archean Tectonic Regimes by 2-Dimensional Finite Element Code
Project Summary
Many lines of evidence suggest that heat loss from the earth should have been significantly greater in the Archean. The presence of high temperature komatiites, greater radiogenic heat production and heat from the secular cooling of the earth all imply higher mantle temperatures in the Archean. However, these lines of evidence are difficult to reconcile with Archean metamorphic PT data, diamond thermobarometry, mantle xenoliths in kimberlites, the ominous lack of minimum melting granites and estimates for crustal thickness which all suggest that geothermal gradients in the Archean, at least on the continents, were not very different from today. This paradox presents problems for reconstructing Archean tectonic processes and environments. … Read more…
Seafloor imaging east and south of Australia
Project Summary
Data from three recent cruises on N.O. L’Atalante are used in collaboration with AGSO to use backscatter and bathymetry data for seafloor classification, and to reconstruct the tectonic and sedimentary history of selected areas, also based on 3.5 kHz, seismic reflection, gravity and magnetic data.
Sponsors
Australian Geological Survey Organization
Environment Australia … Read more…
The Mid-Cretaceous seafloor spreading pulse: fact or fiction?
Project Summary
A major debate in Geoscience is centred on the hypothesis that a massive pulse of rapid seafloor spreading occurred during the mid-Cretaceous (~120-80 Ma). It has been suggested that such a pulse caused prolonged magnetic field stability, large igneous provinces, a sea-level highstand, variations in atmospheric CO2 and anoxia, but doubts have been raised about its existence. We propose to test this hypothesis by creating complete palaeo-seafloor age grids for the last 130 m.y. They will serve as input for 3-D spherical convection models, whose output will be groundtruthed by plate kinematics, results from mantle tomography and by the uplift-subsidence history of cratons. … Read more…