Just add water: a recipe for the deformation of continental interiors

A. Putnis, T. Raimondo, N. Daczko: Support by ARC DP (commenced 2016)

Summary: By integrating geochemical, geochronological and microstructural datasets, this project aims to provide a novel framework for fluid-rock systems in the lithosphere. Plate tectonics argues that continental interiors are usually stable, rigid and undeformable, yet mountain belts have formed in these locations. Their existence suggests that strong crust can be weakened to allow the accommodation of deforming forces, but the underlying causes for this change in behaviour are not clear. This project aims to investigate the largely unexplored impact of fluid flow on the characteristics of intraplate deformation. This would improve our understanding of what modulates the strength of continental crust, including its susceptibility to seismic activity, and the ways in which fluids interact with the deep crust, including their mineralisation potential.

Mechanisms of proxy uptake in biominerals

D. Jacob, S. Eggins, R. Wirth: Support by ARC DP (commenced 2016)

Summary: This project plans to combine nano-analytical and aquaculture methods to develop new models that improve the reliability of paleoclimate reconstructions. The compositions of shells and skeletal materials of marine invertebrates are essential archives for quantifying temperatures and environmental conditions before modern climate records began. However, their reliability relies on understanding their formation. Emerging knowledge from material sciences indicates that these biocarbonates form via transient precursors rather than direct precipitation from seawater, profoundly affecting their interpretation. This project plans to transfer this new understanding to the earth sciences using nanoscale analytical methods including in vitro geochemical partitioning experiments. This would enable realistic models for geochemical proxy behaviour to be developed, significantly improving paleoclimate interpretations and assessments of ocean acidification effects on marine calcifiers.

Rehydration of the lower crust, fluid sources and geophysical expression

M. Hand, C. Clark, D. Hasterok, T. Rushmer, S. Reddy, B. Hacker: Support by ARC DP (commenced 2016)

Summary: This project aims to explore a long-standing mystery: the origin of deep crustal electrical conductors detected by magnetotelluric imaging of tectonically stable crust. These features occur in cratons of all ages, and commonly cross-cut structures and lithologies. This project aims to investigate the hypothesis that such features are the record of ancient deep crustal fluid flow, which modified the rocks’ electrical properties. Using an exceptionally exposed natural laboratory preserving large-scale rehydration of anhydrous lower crust, the project plans to determine the source of fluids and the compositional changes they induced. It then plans to experimentally determine changes in resistivity induced by fluid flow and use that data to model the magnetotelluric response at crustal scale.

To develop a geophysically relevant proton conduction model for the Earth’s upper mantle

S. Clark, J.C. Afonso, A. Jones: Support by ARC DP (commenced 2016)

Summary: This project is dedicated to developing a proton conduction model for the Earth’s upper mantle to allow for correct interpretation of magnetotelluric data such as those currently being collected by the Australian AusLAMP initiative.

The global consequences of subduction zone congestion

L. Moresi, P. Betts, J. Whittaker, M. Miller: Supported by ARC Discovery (commenced 2015)

Summary: This project will use a combination of 3D geodynamic modelling, plate kinematic reconstruction and geological and geophysical synthesis to determine how congested subduction zones influence plate kinematics, subduction dynamics and tectonic evolution at orogen and global scales. The project aims to deliver a transformation change in understanding the links between congested subduction, mantle flow, trench migration, crustal growth, transitions between stable convergent margin configurations and deformation in the overriding plates of subduction zones. Determining these relationships is significant because it will provide dynamic context to interpret the geological record of ancient convergent margins, which host a large percentage of Earth’s metal resources.

Timescales of mixing and volatile transfer leading to volcanic eruptions

H. Handley, S. Turner, M. Reagan, J. Barclay: Supported by ARC Discovery (commenced 2015)

Summary: The short-lived lead isotope, 210Pb, has the unique ability to place timescale constraints on volcanic processes, such as the input, mixing and degassing of magma. These processes are believed to be of fundamental importance in the triggering of volcanic eruptions. This project will measure 210Pb isotopic compositions and elemental diffusion profiles in crystals of volcanic rocks that represent the end members of mixed magmas to constrain the volume and timescale of volatile transfer from magmatic recharge and also the time between magma mixing events and eruptions. The project aims to test the paradigm that magma recharge triggers volcanic eruptions and aims to yield significant outcomes for understanding eruption triggers at hazardous volcanoes.

Migmatites, charnockites and crustal fluid flux during orogenesis

I. Fitzsimons, M. Holness, C. Clark: Supported by ARC Discovery (commenced 2015)

Summary: Migration of volatile fluid and molten rock controls many Earth processes including rock deformation and the formation of mineral and energy deposits. Deep crustal fluids are hard to study directly, and their characteristics are usually inferred from lower crustal rock brought to the surface by erosion. For over 30 years one such rock called charnockite has been used to argue that lower crust is dehydrated by influx of carbon dioxide-rich fluid, while other evidence supports dehydration by water extraction in silicate melt. This project aims to use the shape, distribution and chemistry of mineral grains to trace the passage of volatiles and melt through charnockite, constrain the nature of lower crustal fluids and resolve a long-standing controversy.

How the Earth works- toward building a new tectonic paradigm

Z.X. Li: Supported by ARC Laureate Fellowships (commenced 2015)

Summary: This fellowship project aims to build on the latest technological and conceptual advances to establish the patterns of Earth evolution, and use this information to examine a ground-breaking geodynamic hypothesis which links cyclic plate aggregation and dispersion to deep Earth processes. Half a century after the inception of plate tectonics theory, we are still unsure how the Earth ‘engine’ works, particularly the forces that drive plate tectonics. The project involves extensive national and international collaboration to potentially create a paradigm shift in our understanding of global tectonics, and hopes to contribute to an understanding of the formation and distribution of Earth resources to provide a conceptual framework for their exploration.

From Core to Ore: emplacement dynamics of deep- seated nickel sulphide systems

M. Fiorentini: Supported by ARC Future Fellowship (commenced 2012)

Summary: Unlike most mineral resources, which are generally concentrated in a wide range of crustal reservoirs, nickel and platinum are concentrated either in the core or in the mantle of our planet. In punctuated events throughout Earth history, large cataclysmic magmatic events have had the capacity to transport and concentrate these metals from their deep source to upper crustal levels. This project aims to unravel the complex emplacement mechanism of these magmas and constrain the role that volatiles such as water and carbon dioxide played in the emplacement and metal endowment of these systems.

The timescales of Earth-system processes: extending the frontiers of uranium-series research

H. Handley: Supported by ARC Future Fellowship and MQ (commenced 2012)

Summary: This project will advance our understanding of the timescales of Earth processes using short-lived (22 to 380,000 years) isotopes. The results will provide better constraints on the timescales of magmatic processes and frequency of large-scale eruptions for volcanic hazard mitigation and also soil production rates for landscape erosion studies.

A new approach to quantitative interpretation of paleoclimate archives

D. Jacob: Supported by ARC Future Fellowship and MQ (commenced 2013)

Summary: Skeletons of marine organisms can be used to reconstruct past climates and make predictions for the future. The precondition is the knowledge of how climatic and environmental information is incorporated into the biominerals. This project will use cutting-edge nano- analytical methods to further our understanding of how organisms build their skeletons.

New insights into the origin and evolution of life on Earth

D. Wacey: Supported by ARC Future Fellowship and MQ (commenced 2014)

Summary: This project aims to provide new insights into the origin of life on Earth, life’s diversification through the Precambrian, and the co-evolution of life and early Earth environments. It will be discipline-leading in that it will take the study of early life to the sub-micrometre and hence sub-cellular level. This will facilitate new opportunities for identifying the types of life present during early Earth history, their metabolisms, cellular chemistry and interactions with their environment. This project aims to also provide new search engines and more robust assessment criteria for life on other planets, and help to resolve specific scientific controversies, for example, the validity of claims for cellular life from 3.5 billion-year-old rocks.

Roles of deep-Earth fluid cycling in the generation of intra-continental magmatism

X.C. Wang: Supported by ARC Future Fellowship and MQ (commenced 2014)

Summary: This project aims to test a provocative and potentially ground-breaking hypothesis that fluid released from subducted oceanic slabs and stored in the mantle transition zone, may trigger or control some major intra-plate geotectonic phenomena. It aims to provide a self-consistent model that links geological processes occurring at plate boundaries with those far-field effects well away from plate boundaries via deep-Earth fluid cycling. The outcomes of this project aim to help to better understand links between plume and plate tectonic processes in the first-order dynamic system of Earth, and identify ways to improve success in future mineral exploration.

How the Earth moves: Developing a novel seismological approach to map the small-scale dynamics of the upper mantle

Y. Yang: Supported by ARC Future Fellowship (commenced 2013)

Summary: The concept of small-scale convection currents from about 100-400 km below the Earth’s surface is a model proposed to explain the origins of intraplate volcanoes and mountains. However, direct evidence for the physical reality of small-scale convection cells is generally weak. This project will develop a novel seismological approach combining both ambient noise and earthquake data that can image such small-scale upper mantle convection. The outcomes of this project will help to fill the gap left in the Plate Tectonic paradigm by its inability to explain intraplate geological activity (volcanoes, earthquakes, mountains), which would be a significant step towards unifying conceptual models about how the Earth works.

Earth’s origin and evolution: a sulphurous approach

O. Alard: Supported by ARC Future Fellowship (commenced 2015)

Summary: This project aims to shed new light on global element cycles in the deep Earth and how they connect to the evolution of the exospheres - one of the hottest topics in geosciences. It also aims to produce key knowledge of the extraction and transport of elements from the deep Earth to the surface, which may provide valuable information for resource exploration. Using novel integrated elemental and isotopic approaches, this program aims to track the origin and fate of sulfur, selenium and tellurium during accretion and subsequent redistribution in fluids to Earth’s surface. This new knowledge is critical to understanding how these and other elements of strategic and economic importance, such as the Platinum Group Elements, are extracted from the deep Earth and transported to the surface.

Measuring mantle hydrogen to map ore fluids and model plate tectonics

K. Selway: Supported by ARC Future Fellowship (commenced 2015)

Summary: The goal of this project is to use magnetotellurics to measure mantle hydrogen contents to aid in the discovery of new mineral deposits. Hydrogen controls the strength of Earth’s mantle and is a vital component of the systems that form giant ore deposits. However, mantle hydrogen content is unconstrained. Ore-forming fluids hydrate the mantle pathways on which they travel. The first aim of this project is to image these fluid pathways to improve mineral exploration techniques. Plate tectonic models assume that the lithospheric mantle is dehydrated but existing data from magnetotellurics and mantle rocks show high hydrogen contents. The second aim of this project is to create a map of the hydrogen content of the plates, which may lead to new models for continental evolution and mantle dynamics.

A new approach to revealing melting processes in the hidden deep Earth

A. Giuliani: Supported by ARC DECRA (commenced 2015)

Summary: Kimberlite magmas are very rich in volatiles (for example carbon dioxide and water); they are the major host of diamonds and provide the deepest samples from Earth’s mantle. The primary compositions of these melts can provide unique information on the nature of the deep mantle. However, kimberlite melts mix and react with wall rocks on the way up, obscuring their primary composition. To see through these secondary processes, the project aims to use a novel approach integrating the study of melt inclusions in magmatic minerals with analysis of radiogenic and stable isotopes, and investigating reactions between kimberlite magmas and wall-rock fragments. The project aims to provide new understanding of the constraints on melting processes and recycling of crustal material in the deep mantle.

A new approach to revealing the composition of kimberlite melts and their deep mantle source

A. Giuliani: Supported by a Marie Curie Grant (commenced 2015)

Summary: The overarching aim of this project is to provide novel constraints on the composition of the Earth’s deep mantle, particularly its volatile content, by undertaking an innovative geochemical and isotopic study of the deepest formed melts on Earth: kimberlites. Kimberlite melts are derived from depths in excess of 150-200 km. They are important as the major host of diamonds because they entrain xenoliths (i.e. fragments) of upper mantle and deep crustal rocks during ascent to the surface, providing a major source of information about the geochemistry of the deep Earth. Despite their importance, the composition of primary kimberlite melts and their exact mantle source are hotly debated issues. This is due to contamination of kimberlite melts by mantle and crustal rocks during magma emplacement and near surface alteration of primary kimberlite mineralogy. To determine the composition of primary kimberlite melts, I will employ a novel approach that combines radiogenic (Sr-Nd-Pb) and stable (C-O) isotope fingerprinting of melt inclusions in kimberlitic magmatic minerals (i.e. olivine and spinel). This approach will constrain whether the carbonate-dominated melt inclusions truly represent examples of pristine kimberlite magma by quantifying processes like crustal contamination and degassing that may have altered the melt composition. I will investigate kimberlites from targeted localities from different parts of the world (South Africa, Canada, Greenland, Russia) and of variable ages (Proterozoic to Cretaceous) to assess if there are spatial and/or temporal controls to kimberlite composition. This information would provide important new constraints on the global cycle of volatiles through geological time.

IGCP project: Supercontinent cycles and global geodynamics

Z.X. Li, D. Evans, S. Zhong and B. Eglington and Co-Leaders, and around 170 members from around the world: Supported by UNESCO-IUGS IGCP (commenced 2016)

Summary: In this project, we will bring together a diverse range of geoscience expertise to explore the occurrence and evolution history of supercontinents through time, in the process to construct global databases of geotectonics, mineral deposits, and the occurrences of past mantle plume events. We will further utilise all information collected to conduct better-constrained geodynamic modelling on how the Earth’s engine works in the first order, and how the supercontinent cycles interacted with the mantle to produce episodic and unevenly distributed Earth resources.

Australian membership of the International Ocean Discovery Program

R.J. Arculus, E.J. Rohling, A.P. Roberts, N.F. Exon, C.J. Yeats, S.Y. O’Reilly, S.C. George, D. Muller, J.C. Aitchison, J.M. Webster, M.F. Coffin, P.M. Vasconcelos, K.J. Welsh, T.C. McCuaig, A.D. George, C.G. Skilbeck, A.T. Baxter, J.M. Hergt, S.J. Gallagher, C.L. Fergusson, C.R. Sloss, A.D. Heap, W.P. Schellart, J.D. Stilwell, J.D. Foden, A.P. Kershaw, W.R. Howard, M.B. Clennell, J.J. Daniell, L.B. Collins: Supported by ARC LIEF (commenced 2014)

Summary: This project is for an Australian membership of the International Ocean Discovery Program. The Program will recover drill cores, situate observatories, and conduct down-hole experiments in all the world’s oceans from lowest to highest latitudes to address fundamental questions about Earth’s history and processes within four high-priority scientific themes: climate and ocean change - reading the past and informing the future; biosphere frontiers - deep life, biodiversity, and environmental forcing of ecosystems; Earth connections - deep processes and their impact on Earth’s surface environment; Earth in motion - processes and hazards on a human time scale.

Australian virtual experimental laboratory: a multimode geoscience facility

S. Foley, J. Mavrogenes, A. Putnis, J. Brugger, S. Clark, H. O’Neil, A. Cruden, K. Evans: Supported by ARC LIEF (commenced 2016)

Summary: This project aims to establish seven types of high-pressure equipment to form a multi-node experimental laboratory at four locations across Australia. Experiments conducted at the high pressures and temperatures of the internal Earth form the basis of our knowledge about the physical and chemical processes that drive geological processes such as plate tectonics, melting to form volcanoes, and the formation and movement of fluids that concentrate precious metals into valuable ore deposits. The new facility may enable major advances in fields such as mantle geodynamics and element transport in fluids, improving our understanding of internal Earth processes and ore deposit formation and location. It also includes portable systems, which can be used in synchrotron applications.

NanoMin: quantitative mineral mapping of nanoscale processes

M. Kennedy, C. Sorrell, D. Haberlah, D. Dewhurst, S. Turner, D. Gore, S. O’Reilly, M. Van Kranendonk, J. Foden, P. Nelson, M. Haghighi, P. Le-Clech, C. Ward, P. Koshy, N. Sherwood: Supported by ARC LIEF (commenced 2016)

Summary: The project seeks to establish an electron microscope-based mineral mapping and analysis facility to provide rapid, quantitative and statistically reliable mineralogical, petrographic and metallurgical data unobtainable by other means in fine-grained materials. The proposed equipment can identify minerals in complex mixtures of sub-µm-grain size materials by virtue of an integrated software and hardware system called NanoMin which incorporates a spectral deconvolution engine combined with a mineral spectra database. A key limitation in understanding complex materials is sub-micron to nanometre scale spatial variability of mineralogical phases. Imaging and quantifying these phases is now possible with the NanoMin system. This promises to open up petrological, geobiological, and materials science research in complex fine-grained materials.

The Ediacaran- Silurian palaeogeography of western Yangtze Block and its tectonic linkage with the Gondwana assembly

W. Yao, J. Wang, X. Zhou: Supported by the China Geological Survey and CU (commenced 2015)

Summary: This project targets the Ediacaran-Silurian sedimentary packages on the western margin of the Yangtze Block, by analysing its sedimentary facies and environments, tracking the provenances of the targeted sedimentary detritus as well as the basin fillings. Based on the sedimentary facies and provenance results, it aims at correlating the western Yangtze Ediacaran- Silurian sedimentary strata with the coeval sedimentary packages of other continents on the northern Gondwana margin (e.g. north India, western Australia etc.), and investigating the paleogeographic linkages amongst those areas. Together with the well-known paleogeographic link between the Cathaysia Block and northern Gondwana during the Ediacaran-Silurian, this project will evaluate the paleogeography of South China in the supercontinent assembly and its geodynamic significance.

Genesis of comb quartz layers: case studies from porphyry Cu deposits at Qulong, Tibet and Now Chun, Iran

Z. Yang, Y. Lu: Supported by NSFC (commenced 2015)

Summary: Two hypotheses have been proposed to account for formation of comb quartz layers (also unidirectional solidification textures, UST). One concept proposes that these textures have grown from pockets of exsolved magmatic fluid located between the magma and its crystallised border, but the other proposes that they have precipitated directly from a crystallising silicate melt. To test these hypotheses, as well as to investigate nature and source of primitive ore-forming fluids in porphyry Cu systems, comb-layered quartz from Qulong and Now Chun porphyry Cu deposits have been selected for the following studies. Features to be studied include: (1) their distribution, occurrence and petrographic characteristics; (2) their spatial and genetic relationships with Cu mineralisation; (3) characteristics of melt/fluid inclusions (e.g. composition, formation temperature, Cu content) in comb-layered quartz; and (4) their elemental and oxygen isotopic geochemistry. The aims of this study are to: (1) document the nature and variation of initial ore-forming fluids in the two deposits; (2) clarify the genesis of comb quartz layers; and (3) identify the sources of ore-forming fluids for porphyry Cu system.

China-Western Australia Seismic Survey (CWAS)

L. Zhao, H. Yuan: Supported by the Institute of Geology and Geophysics, Chinese Academy of Sciences (commenced 2016)

Summary: IGGCAS, Macquarie and GWSA will install a 900 km-long dense (station spacing of 10-15 km) seismic profile across the Western Australia from Port Hedland to the southwestern border of the Kimberley Craton. The project will include 80 broadband seismic stations for 18 months from April 2017 to October 2018 with IGGCAS to provide seismic instruments for 60 stations. A test station was installed in Oct 2016.

From space to the deep Earth

J.C. Afonso, J. Ebbing: Supported by Germany-Australia Joint Research Cooperation Scheme and MQ University (commenced 2016)

Summary: We will develop a novel joint analysis of satellite-derived gravity-magnetic datasets and land-based seismic data within a 3D probabilistic inversion framework. This project thus marks the beginning of a new field in integrated Earth imaging methods and provides an unprecedented opportunity to produce the first images of the thermal and mineralogical structure of the Earth’s lithosphere. We will apply this method to GOCE and Swarm satellite data, as well as to global seismic data, to improve our understanding of the roles of lithospheric vs deep mantle mechanisms in controlling near-surface processes. The outcomes of the project will also provide key information for society-relevant activities such as ore and energy exploration and natural hazard assessment.

Maintaining and upgrading the Global Palaeomagnetic Database

S.A. Pisarevsky: Supported by NSFC University of Oslo (commenced 2015)

Summary: Maintaining and upgrading the Global Palaeomagnetic Database (GPMDB) (http:// www.ngu.no/geodynamics/gpmdb/), which was originally developed by McElhinny and Lock (1996, Surv. Geophys. 17, 575). Updated versions of the GPMDB will be delivered electronically in Microsoft Access database format twice a year (June and December). At Oslo University the updated versions will subsequently be incorporated in both the GPMAP (Torsvik and Smethurst 1999, Computers & Geosciences 25, 395-402) and GPlates (www.gplates.org) software and made available electronically online.

Defining mineral systems footprints in the Edmund Basin of the Capricorn Orogen

H. Lampinen, S. Occipinti: Supported by the Australian Society for Exploration Geophysicists (commenced 2014)

Summary: The results of this project will lead to a fully integrated and ground truthed geological-geophysical map and a 3D basin architecture model containing the information and analysis of the mineral assemblages detected from the spectral signatures. In addition, the project aims to produce a detailed methodology in how to use the selected datasets as an exploration tool.

Carbon isotope evolution of the deep Earth from coupled C-O isotope SIMS measurement of carbonates in kimberlites

A. Giuliani, M. Castillo-Oliver: Supported by a Europlanet 2020 Research Award (commenced 2016)

Summary: Kimberlites are carbonate-rich volcanic rocks that represent the deepest-derived melts at Earth’s surface. They have formed since at least ~2.5 Ga and represent a unique probe of the deep Earth. Understanding the C isotope evolution of kimberlites and their mantle source(s) through space and time can provide fundamental new clues on the time-integrated deep C cycle. To constrain the C-O isotope composition of kimberlites, we will examine the C-O isotope composition of kimberlite carbonates by SIMS. Selected samples include kimberlites from South Africa, Canada, Finland, Brazil and Australia emplaced at between 2.0 Ga and 50 Ma and whose petrography and geochemistry has been thoroughly investigated. SIMS analyses of the C-O isotope composition of texturally and geochemically well-characterised carbonates will permit, for the first time, determination of the magmatic signature of kimberlite carbonates, which was previously hampered by the employment of bulk analytical techniques to (partially) altered samples. This approach, coupled with other isotopic systems (e.g. S, N) that are sensitive to crustal contribution, will allow evaluation of the extent of crustal C recycling in the kimberlite source over the last 2.0 Ga. This project has implications for understanding of the temporal evolution of Earth’s mantle and exosphere and potentially major implications for other terrestrial planets.