Appendix 2: Plans for 2015

Two years after commencement of the CCFS Foundation Projects, individual projects have matured, cross-node communications have developed, and new research directions and collaborations have emerged.  The research already completed has identified new perspectives and asks new questions: synergies between Foundation Projects and the Technology Development Projects have grown, fulfilling the original strategy.  The new project descriptions are given in detail here.

Most Foundation Projects (FP) have proven robust research anchors core to CCFS goals and have developed new aims and directions; some have been completed and others have conceptually converged so align (and merge) with other Foundation Projects, together defining creating new and exciting goals.  For example, original FP projects on large granite blooms (FP 3) and Dynamics of Earth’s mantle (2b) are completed as envisaged, whereas aspects of understanding the nature of deep Earth fluids through diamond research (FP 8) have been combined into FP 1 (TARDIS II) and 4-D lithospheric evolution (FP 9) into FP 2 (Multi-scale four-dimensional genesis).  There have been major re-alignments of several Foundation Projects, adjusting their scope to achieve the new scientific goals.  Aspects of geodynamic processes and fluid effects, at micron to macro scales, during subduction processes have taken on increased importance, and are now integral to most in projects.

FOUNDATION RESEARCH PROJECTS FROM MID 2014

WHOLE OF CENTRE TECHNOLOGY DEVELOPMENT

As this Annual Report goes to print, details of these projects (including titles and funding allocations) are being finalised for implementation from mid 2014 as the original 3-year projects are completed.

FP 1: TARDIS II: DEEP-EARTH FLUIDS IN SUBDUCTION ZONES, OPHIOLITES, AND CRATONIC ROOTS

The newly designed TARDIS project incorporates the previously independent Foundation Project Diamond genesis: Fluids in deep Earth processes, with an added specific goal of following up and explaining intriguing discoveries about the process of ultra-deep subduction in continental collision zones.  The former projects converged toward studies of the super-reducing, ultra-high-pressure (SuR-UHP) diamond-bearing mineral assemblages found in ophiolites from Tibet and the Polar Urals.  The SuR-UHP assemblage includes a wide range of alloys, native metals, oxides, carbides, and some silicates.  

The nature of the SuR-UHP environment and the tectonic setting and evolution of the UHP ophiolites will be constrained by analyses of the contents and aggregation state of N in the nitrogen rich ophiolitic diamonds, supplemented by in situ FTIR measurements of N contents and aggregation states, isotopic analysis of N and C by SIMS, and measurements of 3He/4He ratios and other noble gases.  These will help to establish the origin of the diamonds, following up initial indications that the rocks experienced a short burial and exhumation history and rapid cooling to low temperatures.  Studies of diamonds, their inclusions, and the amorphous carbon will include techniques such as NMR and FIB-TEM, benefitting from the broadened base of expertise in CCFS with the new AI Dorrit Jacob, CI Yingjie Yang (Beijing) and R. Wirth at Potsdam.  The investigation of the “amorphous C” will have a high priority to follow up the suggestion that this material may represent a natural occurrence of a polymer-based ceramic material.

In situ measurements of the isotopic ratios of a number of elements in their oxidised and reduced forms using a mixture of SIMS and LA-MC-ICPMS will test the possibility that the exceptionally reducing conditions may have caused isotopic fractionations between phases such as native metals, carbides, oxides and silicates.  The analysis of Si isotopes in SiC from several environments has been funded as a pilot sub-project as a new Technology Development initiative.  Small-scale variations in Fe3+/Fe2+ and Cr2+/Cr3+ will be ascertained by XANES mapping at the Australian Synchrotron.  These in situ and mapping techniques will improvements on the currently available bulk analyses by Mössbauer spectroscopy.

Indications of extreme pressures will be intensively investigated.  Trace-element spot analyses of olivines will check them for signs of inverted wadsleyite or ringwoodite, and the suggestion that olivines in the massive chromitites have shorter bond lengths (Mg-O, Si-O) than in shallow environments will be re-investigated.  If confirmed, this could become a “fingerprint” that could be applied to other ophiolites to detect similar UHP histories.  Dynamic modelling of deep subduction and collision will cross-check the conclusions from the geochemical and mineralogical investigations, integrating this work with FP 3 (Two-phase flow).  Petrological and improved Os isotope geochronological studies will constrain rock properties, including density and its changes during exhumation.  Experimental studies will be introduced in the last half of the project, following installation of the new high-pressure laboratory.  Aims could be the investigation of the formation of baiwenjiite by subduction-dehydration of antigorite at Transition Zone conditions, and element partitioning in the high-P polymorphs of chromite under variable redox conditions.

FP 2: MULTI-SCALE FOUR-DIMENSIONAL GENESIS, TRANSFER AND FOCUS OF FLUIDS AND METALS

A combination of the two previous Foundation Projects on metal sources and transport mechanisms and 4D lithospheric controls on mineral system distribution, FP 2 has been re-aligned to bring the separate studies of fertility, architecture and geodynamics into a single umbrella project.  Previous CCFS experiments on melt/fluid pairs have demonstrated the success of the experimental technique.  These studies will now be expanded to look at the role of other volatiles (S, Cl, CO2, Br) in the transport of metals, and to add PGE and Au to the existing suite of base metals.  The range of conditions will also be expanded to additional pressure-temperature windows and oxidation states.  This will in turn expand the applicability of the experiments to a greater range of mineral systems including Ni-Cu-PGE, Cu-porphyry systems and PGE layered intrusions, with the goal of resolving the debate whether these result from sulfide segregation or fluid metasomatism.  A new branch of studies will integrate the now-diverse CCFS expertise in investigating the role of ultrapotassic-potassic rocks in the redistribution of metals and volatiles from mantle to crust in collision zones.

Recent CCFS work has emphasised the role of lithospheric architecture in the localisation of magmatic provinces prospective for a wide range of mineral systems, including orogenic gold and Cu-(Au) porphyries, Ni-Cu-PGE, and Cu-Mo-Au porphyry systems.  The key pathways that connect geochemical reservoirs and permit efficient fluid flux will be further investigated in field studies in the Ivrea Zone, Southeast Greenland and Tibet.  The critical tectono-metamorphic events that favour the efficient extraction of metals from a fertile source will be investigated by targeting the peridotites of Zabargad (Red Sea), which represent mantle rocks exhumed by hyper-extension during rifting.  These rocks provide the key to establishing the relationship between continental-margin processes and mantle metasomatism and provide a unique opportunity to tease out the importance of extension in fertility enhancement before subsequent modification associated with basin closure.  Expanded use of EBSD will strengthen our knowledge of the key relationship between deformation at the micro-scale and the transfer of key fluids and metals.

FP 3: TWO-PHASE REACTIVE FLOW IN MULTI-COMPONENT DEFORMABLE MEDIA

This project incorporates novel self-consistent thermodynamic modelling and new seismic tomography methods to constrain the thermal and fluid content of the upper mantle.  A thermodynamically consistent scheme that couples deformation, self-generation and migration of porosity (or damage), mass transfer between phases, and reaction within phases is under development in only a few Institutions, and is widely regarded as the frontier of geodynamical methods.  This will enable the CCFS geodynamics group to address problems of significant relevance to the geochemical community, given the clear importance of percolative fluid flow within the solid mantle.

Progress in the investigation of multi-component multi-phase reactive flow (MPMCRF) systems involves overcoming technical difficulties in solving complex numerical problems, analytical, experimental and field studies to constrain important parameters, and understanding the strong scale-related variability in the behaviour of the system of equations.  Two prongs of a three-pronged approach to developing computational tools (Cartesian tool development [Underworld] and CitcomS spherical code capability) have been adopted, and we are currently working on the new code-development aspects.  Underworld’s modelling capabilities will be further developed using Nectar funding.  Applications of this modelling initially will be primarily in areas of flat subduction, where fluid release makes two-phase flow problems of particular importance.  The Farallon slab in the western U.S.A. and a similar situation in South China will be used as examples.

We will adopt the two new methods of Ambient noise tomography and Multiple Plane Wave Tomography in seismic imaging to construct 3D seismic models using data from the extensive broadband Transportable Array component of EarthScope/USArray, which are publicly available.

The thermodynamic modelling will benefit from the expansion of high-pressure experimental facilities at Macquarie over the next two years.  Immediate relevant questions that can be approached experimentally are the mineralogy of material formed by melts and fluids that solidify under lower lithosphere conditions, and the reactions that occur between infiltrating melts and fluids and the lower lithospheric mantle.

P 4: A PLANETARY DRIVER OF ATMOSPHERIC, ENVIRONMENTAL AND BIOLOGICAL EVOLUTION THROUGH TIME

This re-vamped project incorporates the work already conducted on multiple sulfur isotopes into a coherent, integrated plan with a much broader scope that links the previous work into a global framework of changing tectonics through time.  Specifically, we have added three new modules that link ore deposits and life, to investigate how these interact with the lithosphere-hydrosphere boundary through time, and tie changes in these systems to the evolving geodynamic framework of our planet.

The early Earth was a fundamentally different planet: environments, habitats, and atmosphere and ocean compositions have all evolved in concert with changes in the biosphere, and at least some of these coincide with changes in the tectonic style of Earth.  New work modules address [1] Vital pathways: how mantle-derived ultramafic magmas incorporate sulfur to produce ore deposits and how the compositions of these systems have evolved through time.  A continuation of this work will be applied to Mars, as a way of comparing the developmental history of these terrestrial planetary neighbours. [2] Critical interfaces: what occurs where the lithosphere meets the exosphere when and where life appears?  The low- metamorphic grade rocks of the Turee Creek Group, Western Australia, preserve a conformable record of the transition from early Earth (anoxic exosphere, warm climate, hotter mantle) to more modern Earth (oxidised exosphere, cold climate, cooler mantle).  [3] Global element cycles: chemical proxies of microbial metabolism are preserved in the cycles of C, S, Fe and N isotopic systems.  Here two specific intervals, the Mesoarchean, when modern-style plate tectonics appears to have begun, and the Neoarchean to early Proterozoic transition, when atmospheric oxygen rose and chaos appears to have reigned in the biosphere.  [4] Planetary driver: How do crust formation and episodic rapid subduction affect heat flow and life environments at a global scale?  We will elaborate on the causative drivers, undertaking whole-Earth modelling of the effects of subduction and its effects on atmospheric composition and temperature.

FP 5: DETECTING EARTH’S RHYTHMS: AUSTRALIA’S PROTEROZOIC RECORD IN A GLOBAL CONTEXT

This Foundation project maintains its previous aims, and will build on its solid base of results from the first two years, concentrating during the next period on paleomagnetic analysis of the Mesoproterozoic Morawa Lavas of Western Australia, and the 2.4 Ga Erayinia mafic dykes in the southwestern Yilgarn Craton.  Additional sequential targets are the Bangemall Basin, sampled in 2013, and Paleoproterozoic rocks of the Kimberley region.  International collaborative work will be continued, including a number of offshore targets, and results will be published as further syntheses of Proterozoic paleomagnetism and paleogeography.

FP 6: FLUID REGIMES AND THE COMPOSITION OF THE EARLY EARTH

Further work on both early Archean terrestrial samples and meteoritic material representative of the terrestrial planets will continue.  Terrestrial samples from several continents will be studied: Antarctic samples from both Enderby Land and Kemp Land will be further investigated to resolve the origin of the ‘patchy’ distribution of Pb and Ti, and will include additional synchrotron and Raman analyses.  The Jack Hills traverse will be interpreted and published, focusing on the distribution of Proterozoic sedimentary rocks and the timing of metamorphism.  Analytical work will be undertaken on the Illarra Greenstone Belt samples that contain components older than 4.0 Ga, and work will continue on zircons extracted from the oldest rocks in Canada and Greenland.  The work on the North Atlantic Craton will be augmented in the future by samples from key localities in Labrador, to which a field excursion is planned for 2014.  A thorough investigation of the oldest rocks in the North China Craton will continue in association with the Chinese Academy of Geological Sciences.

As regards extra-terrestrial samples, the geochemical and micro-structural data obtained on Zagami and Nakhla sub-samples will be completed, and a new focus will be placed on the composition and significance of carbonates within ALH84001-83, which will require development of suitable carbonate standards.  We will continue our investigations on ALH84001-104, emphasising variations in microstructure and geochemistry across the sample.

FP 7: 3-D ARCHITECTURE AND PRECAMBRIAN CRUSTAL EVOLUTION IN WESTERN AUSTRALIA

Two previous Foundation projects dealing with the evolution of the crust in Western Australia are now folded into one.  Future work on the Western Australian crust will involve more than 20 CCFS scientists, interlinking with several Foundation Projects, as well as independently funded initiatives such as ARC-Linkage funding of a three-year passive-array deployment across the south-eastern margin of the Yilgarn, and a similar passive array for the Capricorn Orogen on the Yilgarn Craton’s northern margin in association with the Distal Footprint Science Investment and Education Fund.  The craton-scale 3D seismic passive-source deployment will greatly improve lithospheric imaging.  Ambient-noise imaging and receiver-function CCP stacking have intermediate resolution in the crust compared with active-source studies, but unprecedented resolution in the cratonic lithosphere.

Collaborative research on the lithospheric evolution and related significant mineralisation of the Yilgarn Craton and its margins, will also be developed in geochemistry, geochronology, geodynamics and modelling.  U-Pb, Hf, and Nd isotope studies will be continued in the northeastern Yilgarn, and extended to the southwest of the craton.  These will be supplemented by Os and Nd isotopic data to develop a mantle-signature database that will assist in determining the relative roles of juvenile mantle and continental lithosphere in mafic/ultramafic rocks and in crustal isotopic mapping.  Testing of existing geodynamic concepts that have been put forward for the Yilgarn Craton will be prioritised, beginning with relatively well-described time slices such as the 2800–2600 Ma tectonic evolution of the eastern Yilgarn Craton. 

The project will continue to acquire and interpret zircon Lu–Hf isotope data, integrating them with other geoscience datasets.  The research will continue to be focused in ‘greenfields’ areas, concentrating on the western Yilgarn Craton, the Albany–Fraser and Capricorn Orogens, the Kimberley region, and basement rocks of the Eucla Basin from 2014.  Additional new samples will be collected during the normal course of GSWA fieldwork to address specific geological problems.  In 2013 more than 1400 analyses were performed despite considerable instrument down-time; it is hoped to surpass this number in the coming years.

TECHNOLOGY DEVELOPMENT PROJECTS

TDP 1: CAMECA ION-MICROPROBE DEVELOPMENT

The ion microprobe has enjoyed increasing usage within CCFS and has become an important entity in the cross-fertilisation of research ambitions, leading to an increased number of applications planned in the near future.  Work on standards and analytical protocols is ongoing, and currently includes multiple sulfur isotopes in sulfide minerals, oxygen and hydrogen isotopes and zirconium isotopes in zircon.  The new pilot projects will extend this to the isotopes of silicon, carbon and nitrogen.

The installation of the new NanoSIMS 50L will likely occur in late 2014, with testing extending into 2015.  Testing the new oxygen ion source should prove to be exciting as this has the potential to increase the spatial resolution for positive secondary ions by an order of magnitude.

TDP 2: FRONTIERS IN INTEGRATED LASER-SAMPLED TRACE ELEMENT AND ISOTOPIC GEOANALYSIS

Further advancement of geochemical methodologies and techniques, particularly involving the new Femtosecond laser microprobe, the Nu AttoM Sector field ICP-MS and the Excite 193nm excimer laser, will continue to play a significant role in the creation of new research initiatives and to be a major factor in attracting new research collaborators.  The development of potential microbeam standards for combined laser ablation ICP-MS and MC-ICP-MS requires characterisation of major and trace elements and isotopic compositions; these are being developed in collaboration with UWA in TP 1.  A new technological initiative involves adaptation of conventional ‘macro’ techniques to micro sample volumes, driven by the availability of ‘contamination-free’ mineral separates using selFrag and the New Wave Micromill (TP 3).  Research into fundamental properties of femtosecond ablation processes in geological materials (firstly silicates, then sulfides, oxides, phosphates, carbonates) focusing on laser-induced isotopic fractionation, will be expanded, and split-stream laser ablation analysis using Q-ICP-MS (U-Pb isotopes) and MC-ICP-MS (Hf isotopes) will be developed.  Work on Li and Mg isotopes will be continued and optimised.

PILOT PROJECTS 2014-2015: A NEW INTITATIVE

In addition to the Foundation Projects, CCFS is providing limited funding for pilot projects for one or two years, commencing in 2014.  These pilot projects were conceived with the aim of “seeding” small project ideas that are not yet far enough developed to compete successfully for grants to conduct the fully-fledged projects.  The aim of the pilot projects is to nurture excellent, risky research ideas and bring them to the stage where they are either competitive for outside funding or become a new strand of a Foundation Project.  The pilot projects were awarded in a competitive proposal round with a view either to folding them into Foundation projects at a later stage, or to giving them from one to two years to unfold their potential with preliminary results to demonstrate that they are competitive to apply for independent funding.  Three of these pilot projects (5, 6, 7) address technology development, particularly new types of in situ analysis.  All involve inter-node collaboration.