Integrating global multidimensional datasets to underpin subduction process modelling during the past 60 million years

Project Report
Understanding the initiation and processes governing subduction remains one of the greatest challenges in geodynamics. Subduction processes affect every aspect of the Earth system, from its control on the thermal and chemical state of the mantle, to its recycling of oceanic lithosphere, sediments, water and volatiles, to its affect on the atmosphere, hydrosphere, biosphere and solid Earth through earthquakes and volcanic eruptions. Moreover, subduction is generally agreed to be one of the primary driving forces of plate tectonics and mantle convection through slab pull and the addition of raw materials into the mantle. Previous attempts to numerically model the initiation and development of a self-sustaining subduction system have relied on instantaneous snapshots and theoretical boundary conditions not well constrained by geological and geophysical observations. However, subduction zones are extremely dynamic and have continuously changing shapes, locations, orientations and physical properties through time. While computer simulations have provided useful insights into some of these problems, the lack of well-integrated observational constraints has limited previous models to various 2D or 3D simplifications. In order to advance our knowledge of subduction and its effects on the interior (mantle) and surface (crust) of the Earth, we propose to create a subduction e-science geoframework, in which observations, plate kinematics through time, geodynamic modelling, and model/data visualisation are seamlessly linked.

This research project will integrate recently developed time-dependent global data sets with geodynamic modelling to allow a quantitative analysis of observations from the world’s subduction zones. We will use our newly completed global palaeo-age grids of the ocean floor, revised global plate kinematics including moving hotspots, palaeo-plate velocity grids, seismic tomography and geological data together with CitcomS/SNARK geodynamic modelling software to:

  • Create a global digital library for subduction containing multidimensional data (e.g., plate kinematic, plate age, seismological, petrological) and 4D model outputs, which will underpin subduction process modelling, spanning the last 60 million years.
  • Determine the flux of subducted crustal fluids into the mantle based on ocean drilling results and our oceanic palaeo-age grids and kinematic models.
  • Constrain mechanisms that control the initiation of subduction.
  • Determine the controls on the dip of the subducted slab through time.
  • Investigate the tectonic, magmatic and thermal effects of ridge subduction on the over-riding plate.
  • Assess the relative importance of key subduction zone parameters on the formation of convergent-margin ore deposits.

Global Digital Library for Subduction Digital Isochrons of the World’s Ocean Floor Subduction and Back-arc Basin Parameters Global Plate Velocity Grids Palaeo-stress of the Australian Plate Software GPlates Project: www.gplates.org

Funding Agency
Australian Research Council Discovery Grant 2005-2007

Project Participants
Dietmar Müller, Primary Investigator, University of Sydney
Mike Gurnis, Primary Investigator, California Institute of Technology
Maria Sdrolias, Research Associate, University of Sydney
Stuart Clark, Postgraduate Student, University of Sydney
Lydia Taylor, Postgraduate Student, University of Sydney
Joanne Whittaker, Postgraduate Student, University of Sydney

Publications Arising from Project
Sdrolias M., Müller, R.D. and Gaina C. In Prep. The Controls on Back-arc Basin Formation. Geochemistry, Geophysics, Geosystems.