Chris Clark

• Professor at Curtin University

Exhumed orogenic belts contain the only physical record of the processing of Earth’s crust during tectonic cycles and are, therefore, the critical regions where constraints on geodynamic processes can be developed. Reconstructing metamorphic field gradients and thermal modeling are key approaches for investigating this record. This study examines t...

Petrochronological investigations of granulite-facies metapelitic rocks from the eastern contact of the Closepet granite in the Central Dharwar Craton (CDC), southern India, provide new pressure–temperature–age (P–T–t) constraints on two seemingly discrete Archean metamorphic events during the Neoarchean and late Paleoarchean eras. Phase equilibriu...

Using petrography, in situ garnet Lu-Hf geochronology, garnet rare-earth element (REE) analysis, zircon U-Pb geochronology and phase equilibrium modelling, we provide unambiguous evidence for Eoarchean granulite-facies metamorphism in the northern Itsaq Gneiss Complex (IGC), southwest Greenland. In situ garnet Lu-Hf geochronology from two samples o...

To constrain the rate of cooling of lower-crustal rocks from an ultrahot orogen, we determined both the age and equilibration temperature of metamorphic zircon from six widely spaced samples of metasedimentary garnet−sillimanite gneiss from the Eastern Ghats Province in eastern India. For the combined data set of metamorphic zircon, concordant date...

The tectonic setting of Tonian orogenic events recorded in the present-day circum-North Atlantic region is uncertain. U-Pb zircon geochronology shows that the Yell Sound and Westings groups (Shetland) and metasedimentary rocks of the Naver Nappe (northern mainland Scotland) were deposited between c. 1050-960 Ma and intruded by mafic, intermediate a...

In situ garnet Lu-Hf geochronology has the potential to revolutionise the chronology of petrological and tectonic processes, yet there is a paucity of well-characterised reference materials to account for laser-induced matrix-dependant elemental fractionation. Here, we characterise two reference garnets GWA-1 (Lu ~ 7.0 μg g-1) and GWA-2 (Lu ~ 8.5 μ...

In situ age and trace element determinations of monazite, rutile and zircon grains from an ultrahigh temperature (UHT) metapelite‐hosted leucosome from the Napier Complex using laser split‐stream analysis reveal highly variable behaviour in both the U–Pb and trace element systematics that can be directly linked to the microstructural setting of ind...

The oldest known evolved (felsic) rocks on Earth (c. 4.03 Ga) are found in the Acasta Gneiss Complex (AGC) in northwestern Canada and represent a fundamental keystone in unravelling the geological processes governing crustal growth and differentiation during the Hadean and early Archean. Although the timing of multiple episodes of magmatism, metamo...

Accessory minerals like zircon, rutile and monazite are routinely studied to inform about the timing and nature of geological processes. These studies are underpinned by our understanding of the transfer processes of trace elements and the assumption that the isotopic systems remain undisturbed. However, the presence of microstructures or Pb-bearin...

Multi-mineral petrochronology can effectively track changes in the thermochemical environment experienced by rocks during metamorphism. We demonstrate this concept using garnet–chlorite schists from the Walter-Outalpa Shear Zone of the southern Curnamona Province, South Australia, which reveal a cryptic and protracted (c. 39 Myr) record of high the...

Some isotopic ratios in minerals like monazite, apatite, and mica can record the thermal response to mylonitization, but such systems may fail to track the time of low-to medium temperature fabric realignment (recrystallization). New analytical methods that allow spatially resolved measurement isotopic ratios in distinct microstructures offer the p...

Chemical heterogeneities along grain boundaries in garnet occur across a wide range of metamorphic conditions, yet the processes underlying their development remain poorly understood. Here we integrate electron backscattered diffraction (EBSD) and atom probe tomography (APT) to evaluate the mechanisms driving nanoscale trace element mobility to def...

The impact of fluid infiltration on the deformation mechanisms that facilitate the development of lower-crustal ductile shear zones is evaluated through a multiscale structural, geochemical, and thermobaric analysis undertaken across a shear zone/wall-rock interface exposed on the island of Radøy in the Bergen Arcs (western Norway). At the outcrop...

Element mobility is a critical component in all geological processes and understanding the mechanisms responsible for element mobility in minerals is a fundamental requirement for many geochemical and geochronological applications. Volume diffusion of elements is a commonly assumed process. However, linear defects (dislocations) are an essential co...

The enigmatic occurrence of Neoarchean- and Proterozoic-aged zircon grains in some samples of metasedimentary rocks from the Jack Hills, Western Australia, that otherwise appear to have been deposited before 3.0 Ga is explained by contamination with embedded zircon grains sourced from transported regolith. Zircon U-Pb age spectra obtained by laser...

In this study, data from garnet‐kyanite metapelites in ultrahigh‐pressure (UHP) domains of the Western Gneiss Region (WGR), Norway is presented. U–Pb geochronology and trace element compositions in zircon, monazite, apatite, rutile and garnet were acquired, and pressure–temperature (P–T) conditions were calculated using mineral equilibria forward m...

The Capricorn Orogen, Western Australia, is a complex orogenic zone that records the convergence and collision of the Archaean Yilgarn and Pilbara cratons in forming the West Australian Craton (WAC), then over one billion years of subsequent intracontinental reworking. Granites associated with these tectonothermal events (the Dalgaringa, Bertibubba...

Glassy melt inclusions are unique geological repositories that preserve evidence of the formation and evolution of mantle and crustal-derived magmas. However, the mechanisms responsible for their preservation in slowly cooled crustal rocks remain contentious, in some part due to their small size (commonly < 10 µm) and the technical difficulty in qu...

The extent to which solid-state volume diffusion modifies rare earth element (REE) abundances in accessory minerals during high-temperature metamorphism governs our ability to link recorded trace element compositions to particular thermal events. We model diffusion of REE in zircon under different temperature–time conditions and show that, for both...

The geometry and composition of deformation-related low-angle boundaries in naturally deformed olivine were characterized by electron backscattered diffraction (EBSD) and atom probe tomography (APT). EBSD data show the presence of discrete low-angle tilt boundaries, which formed by subgrain rotation recrystallisation associated with the (100)[001]...

Epidote eclogites embedded in paragneisses from the Austrian Eastern Alps host rare, decimetre- to metre-sized planar pegmatitic segregations (‘pegmatoids’) that consist of a hornblende–plagioclase–epidote–titanite–quartz assemblage. The pegmatoids cut the primary eclogite foliation at a high angle, show abrupt terminations and exhibit numerous mic...

Traditional approaches to develop 3D geological models employ a mix of quantitative and qualitative scientific techniques, which do not fully provide quantification of uncertainty in the constructed models and fail to optimally weight geological field observations against constraints from geophysical data. Here, using the Bayesian Obsidian software...

Mechanical twins form by the simple shear of the crystal lattice during deformation. In order to test the potential of narrow twins in monazite to record the timing of their formation, we investigated a ca. 1700 Ma monazite grain (from the Sandmata Complex, Rajasthan, India) deformed at ca. 980 Ma, by electron backscattered diffraction (EBSD), tran...

The ca. 2 Ga retrogressed eclogites in the Usagaran Belt in central Tanzania are among the oldest documented eclogites in the world. As such, they have been used to pinpoint the thermal conditions of the onset of modern style subduction on Earth. Two samples of retrogressed mafic eclogite have been interrogated to reconstruct the metamorphic histor...

Phase equilibrium modelling is commonly employed to constrain the pressure–temperature (P–T) evolution of granulite facies rocks, from which their geodynamic setting may be inferred. However, defining a suitable equilibrium volume in such rocks is non‐trivial due to heterogeneities in protolith composition and open system behaviour, including melt...

Characterization of host rocks is an essential step towards understanding the genesis and history of sedimentary rock-hosted mineral deposits. Abra is a sedimentary rock-hosted polymetallic deposit, located within the Mesoproterozoic Edmund Basin, in the central Capricorn Orogen, Western Australia. Stratigraphic analysis of the Abra host rock, coup...

Aluminous metapelitic granulites from the central Namaqua Sector of the Namaqua––Natal Metamorphic Province, South Africa, host partly retrogressed hercynite–quartz assemblages. These assemblages record peak P–T conditions of 860–890°C and 5–5.5 kbar, estimated via thermodynamic modelling and ternary feldspar thermometry. In-situ U–Pb geochronology...

The Delamerian Orogen formed at the final stages of assembly of the Gondwana supercontinent. This system marks the initiation of subduction of the Pacific oceanic lithosphere along a prior rifted and extended passive margin. This paper explores the magmatic consequences following the early Cambrian initiation at the palaeo-Pacific margin in South A...

Correlation of Rodinian and Gondwanan crustal domains relies on a thorough knowledge of those vestiges preserved today. The Bunger Hills hold a critical place in East Antarctica, recording the Mesoproterozoic assembly of Australo-Antarctica in Rodinia and the Neoproterozoic–Cambrian amalgamation of Indo- and Australo-Antarctica in Gondwana. It is s...

Southern India lies in an area of Gondwana where multiple blocks are juxtaposed along Moho-penetrating structures, the significance of which are not well understood. Adequate geochronological data that can be used to differentiate the various blocks are also lacking. We present a newly acquired SIMS U–Pb, Lu–Hf, O isotopic and trace element geochem...

Geochronological data from zircon in Archean tonalite–trondhjemite–granodiorite (TTG) gneisses are commonly difficult to interpret. A notable example is the TTG gneisses from the Lewisian Gneiss Complex, northwest Scotland, which have metamorphic zircon ages that define a more-or-less continuous spread through the Neoarchean, with no clear relation...

Measurements of U–Th–Pb, Lu–Hf and oxygen isotopes as well as selected trace and rare earth elements were carried out on zircon grains from high-grade metasedimentary rocks from the Albany–Fraser Orogen in southwest Australia. Oxygen isotopes from detrital zircon domains yield δ¹⁸O (VSMOW) values ranging from 5.8 to 8.0‰ and exhibit coupled Hf- and...

The extraction of tectonic lineaments from digital satellite data is a fundamental application in remote sensing. The location of tectonic lineaments such as faults and dykes are of interest for a range of applications, particularly because of their association with hydrothermal mineralization. Although a wide range of applications have utilized co...

The age and composition of magmas provide fundamental information to chart the tectonic setting of crustal development through time and hence refine paleogeographic reconstructions. The Biranup Zone of the Albany-Fraser Orogen in southwestern Australia preserves a protracted record of magmatism associated with the formation and subsequent break-up...

This Special Issue comprises a selection of the papers presented at the fifth Granulites and Granulites meeting, held in July 2018 in Ullapool, northwest Scotland. The meeting was in large part a celebration of the outstanding career contribution of Michael (Mike) Brown, who delivered the 51st Hallimond Lecture of the Mineralogical Society of Great...

A tract of amphibolite-facies granitic gneisses and metagabbros in northern Shetland, UK, is here named the Uyea Gneiss Complex. Zircon U–Pb dating indicates emplacement of the igneous protoliths of the complex c. 2746–2726 Ma, at a later time than most of the Archean protoliths of the Lewisian Gneiss Complex of mainland Scotland. Calc-alkaline geo...

The Fraser Zone is a major lithotectonic domain of the Albany–Fraser Orogen, Western Australia, which records Proterozoic modification of the margin of the Archean Yilgarn Craton. The Fraser Zone is volumetrically dominated by gabbroic rocks and their metamorphosed equivalents. However, little is known of the pressure–temperature–time (P–T–t) histo...

A highly residual granulite‐facies rock (sample RG07‐21) from Lunnyj Island in the Rauer Group, East Antarctica, presents an opportunity to compare different approaches to constraining peak temperature in high‐grade metamorphic rocks. Sample RG07‐21 is a coarse‐grained pelitic migmatite composed of abundant garnet and orthopyroxene along with quart...

The Singhbhum Craton and supracrustal provinces in eastern India are one of a few Precambrian terranes that record protracted sedimentation and magmatism spanning the Paleoarchean to Neoproterozoic. A paucity of robust geochronological and isotope geochemical data and the perpetuation of poor-quality data have hampered petrogenetic interpretations,...

Titanite can be found in rocks of wide compositional range, is reactive, growing or regrowing during metamorphic and hydrothermal events, and is generally amenable to U‐Pb geochronology. Experimental evidence suggest that titanite has a closure temperature for Pb ranging from 550 to 650 °C and thus, titanite dates are commonly interpreted as coolin...

In our study we explore the applicability of rutile as a pathfinder for orogenic gold deposits, which are an important source of this metal worldwide. We analysed rutile associated with orogenic Au deposits from three different Precambrian terranes, the Capricorn Orogen, the Barberton Greenstone Belt and the Ashanti Belt, all of which formed under...

Here we present results of the first ⁴⁰Ar/³⁹Ar dating of osumilite, a high‐temperature mineral that occurs in some volcanic and high‐grade metamorphic rocks. The metamorphic osumilite studied here is from a metapelitic rock within the Rogaland–Vest Agder Sector (RVA), Norway, an area that experienced regional granulite‐facies metamorphism and subse...

The Southern Irumide Belt (SIB) records over one and a half billion years ( c . 2000–500 Ma) of tectonic evolution along the southern Congo Craton margin. To understand this evolution we present U–Pb, Lu–Hf, REE zircon and structural data for the SIB of Zambia, which are used to investigate its formation, evolution and relationship to the Irumide B...

Since the introduction of laser-assisted atom probe, analysis of nonconductive materials by atom probe tomography (APT) has become more routine. To obtain high-quality data, a number of acquisition variables needs to be optimized for the material of interest, and for the specific question being addressed. Here, the rutile (TiO 2 ) reference materia...

Granulite facies cordierite–garnet–biotite gneisses from the southeastern Reynolds Range, central Australia, contain both orthopyroxene‐bearing and orthopyroxene‐free quartzofeldspathic leucosomes. Mineral reaction microstructures at the interface of gneiss and leucosome observed in outcrop and petrographically, reflect melt‐rock interaction during...

Traditional approaches to develop 3D geological models employ a mix of quantitative and qualitative scientific techniques, which do not fully provide quantification of uncertainty in the constructed models and fail to optimally weight geological field observations against constraints from geophysical data. Here, we demonstrate a Bayesian methodolog...

The timing of final assembly and initiation of subsequent rifting of Rodinia is disputed. New rutile ages (913 ± 9 Ma, 900 ± 8 Ma and 873 ± 3 Ma) and published zircon, monazite, titanite, biotite, muscovite and xenotime geochronology from the Capricorn Orogen (West Australian Craton) reveal a significant early Neoproterozoic event characterized by...

A pilot palaeomagnetic study was conducted on the recently dated with in situ SHRIMP U-Pb method at 1134 ± 9 Ma (U-Pb, zircon and baddeleyite) Bunger Hills dykes of the Mawson Craton (East Antarctica). Of the six dykes sampled, three revealed meaningful results providing the first well-dated Mesoproterozoic palaeopole at 40.5°S, 150.1°E (A95 = 20°)...

Unravelling the spatio-temporal evolution of orogenic terranes requires a comprehensive understanding of the duration and extent of metamorphic events and hydrothermal alteration. Commonly used minerals such as zircon and monazite may not fully record geological histories in complex tectonic settings because their elemental constituents do not reac...

Intracontinental rifting of the Capricorn Orogen was accompanied by the emplacement of mafic intrusions at c. 1080 Ma, contemporaneous with deposition of siliciclastic and volcanoclastic sediment in the late Mesoproterozoic Collier Basin. In this work we investigate the provenance of the Collier Basin sediment with U-Pb and trace elements data for...

The extraction of geological lineaments from digital satellite data is a fundamental application in remote sensing. The location of geological lineaments such as faults and dykes are of interest for a range of applications, particularly because of their association with hydrothermal mineralization. Although a wide range of applications have utilize...

The timescales and P-T conditions recorded by granulite facies metamorphic rocks permit inferences about the geodynamic regime in which they formed. Two compositionally heterogeneous cordierite-spinel-bearing granulites from Vizianagaram, Eastern Ghats Province (EGP), India, were investigated to provide P-T-time constraints using petrography, phase...

Intracontinental rifting of the Capricorn Orogen was accompanied by the emplacement of mafic intrusions at c. 1080 Ma, contemporaneous with deposition of siliciclastic and volcanoclastic sediment in the late Mesoproterozoic Collier Basin. In this work we investigate the provenance of the Collier Basin sediment with U-Pb and trace elements data for...

The Napier Complex in East Antarctica preserves a record of ultrahigh‐temperature (UHT) metamorphism during the late Archean to early Palaeoproterozoic. While there is little argument that the UHT metamorphic event began at c. 2580 Ma, the duration over which the rocks resided at UHT has been the subject of intense debate, with estimates for the en...

We present LA–ICP–MS U–Pb monazite and zircon geochronology, trace element chemistry and phase equilibria forward modelling to constrain the P–T–t evolution of the Bunger Hills, East Antarctica. Metasedimentary rocks in the Bunger Hills record evidence for a protracted metamorphic history during the Mesoproterozoic. Taken in isolation, zircon and m...

The Abra Pb-Ag-Ba-Zn-Cu-Au deposit in the Capricorn Orogen, Western Australia is primarily a lead and silver resource currently estimated at 47.8 Mt (indicated and inferred) of 7.3–10.1% Pb and 18–28 gt⁻¹ Ag, although significant Cu-Au zones are also identified. The deposit is unique within sediment-hosted Pb-Zn deposits for its low Zn content, sig...

The Th/U ratios of zircon crystals are routinely used to help understand their growth mechanism. Despite the wide application of Th/U ratios in understanding the geological significance of zircon U–Pb ages, the main controls on the Th/U ratio in metamorphic zircon are poorly understood. Here, phase equilibria modelling coupled with solubility expre...

The widespread use of monazite (LREEPO4) in U-Pb geochronology is underpinned by the assumption that it incorporates negligible amounts of Pb during initial growth, and that radiogenic Pb remains immobile after formation. We have investigated the nanoscale distribution of Pb in monazite from granulite facies rocks of the Sandmata Metamorphic Comple...

Exhumed eclogitic crust is rare and exposures that preserve both protoliths and altered domains are limited around the world. Nominally anhydrous Neoproterozoic anorthositic granulites exposed on the island of Holsnøy, in the Bergen Arcs in western Norway, preserve different stages of progressive prograde deformation, together with the correspondin...

The geochemistry of rutile (TiO2) has recently found its use in mineral exploration with some studies reporting anomalous concentrations of Fe, W, V, Sn and Sb in rutile associated with mineralized ore systems. However, the use of rutile as a prospecting tool is likely to be complicated by the systematic changes in trace element composition with Ti...

Ultrahigh temperature (UHT) granulites in the Eastern Ghats Province (EGP) have a complex P–T–t history. We review the P–T histories of UHT metamorphism in the EGP and use that as a framework for investigating the P–T–t history of Mg–Al-rich granulites from Anakapalle, with the express purpose of trying to reconcile the down pressure-dominated P–T...

India and East Antarctica collided during assembly of the Rodinia supercontinent at around 1 Ga. Granulites related to this orogeny are exposed in the Eastern Ghats Province (EGP) in India, and these are believed to have been contiguous with granulites of the Rayner Province in East Antarctica at that time. In the Indian segment, we describe a shea...

The crystalline basement beneath the Cretaceous to Cenozoic Bight and Eucla Basins, in Western Australia has received comparatively little attention even though it lies on the eastern margin of one of the most mineral resource endowed regions on the planet. This basement is characterized by a complex geological evolution spanning c. 2 billion years...

The Bunger Hills in East Antarctica occupy a pivotal location as the westernmost continuation of the Albany–Fraser Orogen in southwestern Australia. Combined U–Pb, Lu–Hf and oxygen isotope data from the Bunger Hills reveal a previously unrecognised Archean basement (ca. 2800–2700 Ma) of Yilgarn Craton affinity. Results also reveal a Paleo–Mesoprote...

The use of rare earth element (REE) partition coefficients is an increasingly common tool in metamorphic studies, linking the growth or modification of accessory mineral geochronometers to the bulk silicate mineral assemblage. The most commonly used mineral pair for the study of high-grade metamorphic rocks is zircon and garnet. The link from U–Pb...

Neoproterozoic tectonic geography was dominated by the formation of the supercontinent Rodinia, its break-up and the subsequent amalgamation of Gondwana. The Neoproterozoic was a tumultuous time of Earth's history, with large climatic variations, the emergence of complex life and a series of continent-building orogenies of a scale not repeated unti...

A persistent problem in the study of garnet geochemistry is that the consideration of major elements alone excludes a wealth of information preserved by trace elements, particularly the rare-earth elements (REEs). This is despite the fact that trace elements are generally less vulnerable to diffusive resetting, and are sensitive to a broader spectr...

U–Pb and Hf isotopic data from metasedimentary and magmatic rocks from the Windmill Islands in Wilkes Land, East Antarctica, confirm age and crustal evolution links between the Albany–Fraser Orogen and this part of East Antarctica. Detrital zircon age data indicate that the protoliths to the metasedimentary rocks of the Windmill Islands have maximu...

Meta-igneous lithologies of the Cullivoe inlier in NE Yell, Shetland, have tonalite–trondhjemite–granodiorite (TTG) chemistry and yield U–Pb zircon crystallization ages of c. 2856 – 2699 Ma. Formation was coeval with protoliths of the Lewisian Gneiss Complex and the time of major Neoarchaean crustal growth in the North Atlantic Craton. The adjacent...