Major Research Themes – Three Pillars
Research programs within the Centre are focussed to provide maximum synergy for the scope enabled by the resource base. It is not possible to encompass the full range of research about the Earth’s water cycle and deep Earth dynamics. In particular, all applied and mature strategic research is carried out in parallel from other funding sources. Research programs address selected aspects of the following major themes.
Theme 1: Early Earth
The Early Earth - Its formation and fluid budget. This theme focuses on the nature of Earth’s early differentiation and the role of fluids. Ancient (>3 Ga) rocks may yield evidence for early life, and analysing the mass-independent fractionation of Fe and S isotopes will allow us to test the involvement of biological processes in ancient deposits.
The earliest record of Earth’s magnetic field will provide new information on when the core’s geodynamo formed and the geometry and intensity of its field, and will be used to track the movement of Archean tectonic plates. The geochemical nature and dynamic behaviour of the mantle in the early Earth will be assessed using in-situ analysis of targeted minerals from a variety of mantle rock types and tectonic environments, coupled with dynamic modelling.
- to identify the sources of water and other volatiles in the early Earth
- to determine the nature and timing of the earliest crust, hydrosphere and atmosphere
- to use experimental studies to constrain the effects of volatile species and light elements on the separation of the core and the earliest differentiation of the mantle
- to identify the starting point and conditions for the beginnings of life on Earth
Theme 2: Earth’s Evolution
Earth’s Evolution - Fluids in crustal and mantle tectonics; recycling of fluids into the deep mantle; hydrosphere, atmosphere and the deep Earth. Earth has evolved through cycles of crustal formation and destruction, punctuated by “tipping points”, when rapid cascades of interlinked events produced dramatic changes in the composition of the oceans, the oxygen levels of the atmosphere, the tectonic behaviour of the crust and mantle, and the distribution of mineral and energy resources. These events changed the distribution and behaviour of fluids in the deep Earth, and each altered Earth’s evolution irreversibly.
Key issues are: when did subduction start; how did it contribute to the Earth’s cooling; how has this process evolved through time? Isotopic studies will define the rates of continental growth vs recycling through time, and test linkages between crust and mantle events. Geophysical imaging and dynamic modelling will be used to build 3D models of subduction dynamics, thermal evolution and geodynamic cycles. Stable-isotope studies will track water and other fluids in their cycles through the Earth and the hydrosphere.
- to define the processes that produced the earliest persistent lithospheric mantle – the “life raft” on which the continents ride, and the genetic links between crust, mantle and core
- to define the initiation of subduction, the growth rate of the continental crust, and the effects of subducted fluids on the composition and evolution of the deep Earth
- to clarify the nature and causes of major “tipping points” in Earth’s evolution
- to develop 3-D / 4-D kinematic and dynamic reconstructions of the evolution of Earth's mantle and plate geometry with geological and palaeomagnetic records
- to develop new conceptual models for the dynamic interactions between the crust and the deep Earth, and their effects on fluid budgets and mineral and energy systems through time.
Theme 3: Earth Today
Earth Today - Dynamics, decoding geophysical imaging, and Earth resources. Geophysical imagery gives us a snapshot of the current status of the deep Earth but also carries the imprints of past processes. Realistic interpretation of these data will give us new insights into Earth’s internal dynamics and will have practical consequences, e.g. for resource exploration. We will develop thermodynamically and physically self-consistent dynamic codes to model complex processes and their expression in geophysical and geochemical observables. These codes will be used to identify the processes that have controlled the fluid cycle through Earth’s history.
Measurement of the physical properties of potential deep Earth materials at extreme conditions will feed into petrophysical modelling of seismic data in terms of composition, temperature and anisotropy. Measurements of metal complexing at realistic conditions that mimic real ore-system fluids/melts will provide new ways to interpret observations on fluid/melt inclusions in minerals. We will investigate the role of organo-metallic compounds in metal transport, using the capabilities of the Australian Synchrotron, to understand the role of such compounds in the formation of large mineral systems.
- to develop new approaches to integrating petrophysical modelling and geophysical data
- to develop new self-consistent approaches to the interpretation of seismic tomography data in terms of lithospheric structure and deep-Earth dynamics
- to understand the mechanisms of the subduction cycle -- its total fluid budget and the transport of crustal rocks and fluids into the deep mantle
- to analyze the global pattern of mineral and energy resources in the modern and ancient Earth in the context of these approaches
- to develop and evaluate tectonic scenarios for the localisation of mineral and energy resources in the context of physical constraints and geodynamic theory
CCFS participanys at the 2013 SAC meeting, Macquarie University.