21 Result(s)
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Christopher L. Kirkland
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Open AccessCryptic geological histories accessed through entombed and matrix geochronometers in dykes
Deep geology of ancient continental crust can be difficult to access, with direct observation restricted to limited exposures. The age and composition of hidden geology can be gleaned from indirect isotopic mo...
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Onset of the Earth’s hydrological cycle four billion years ago or earlier
Widespread interaction between meteoric (fresh) water and emerged continental crust on the early Earth may have been key to the emergence of life, although when the hydrological cycle first started is poorly c...
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Open AccessTesting in-situ apatite Lu–Hf dating in polymetamorphic mafic rocks: a case study from Palaeoproterozoic southern Australia
In mafic systems where primary mineral assemblages have witnessed moderate- to high-temperature hydrous overprinting and deformation, little is known about the retentivity of the Lu–Hf isotopic system in apati...
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Open AccessEmplacement of the Argyle diamond deposit into an ancient rift zone triggered by supercontinent breakup
Argyle is the world’s largest source of natural diamonds, yet one of only a few economic deposits hosted in a Paleoproterozoic orogen. The geodynamic triggers responsible for its alkaline ultramafic volcanic h...
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Open AccessThermochronometry constraints on south West Greenland passive continental margin development
Passive continental margins (PCMs) represent the interface between the marine and terrestrial realms. However, topographic evolution of PCMs is often difficult to decipher due to paucity of the preserved geolo...
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Open AccessDating mylonitic overprinting of ancient rocks
Deformation in shear zones is difficult to date because mylonites can preserve partially reset pre-existing isotopic signatures. However, mylonites can be key structural elements in terrane recognition, so an ...
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Giant impacts and the origin and evolution of continents
Earth is the only planet known to have continents, although how they formed and evolved is unclear. Here using the oxygen isotope compositions of dated magmatic zircon, we show that the Pilbara Craton in Weste...
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Open AccessRegional zircon U-Pb geochronology for the Maniitsoq region, southwest Greenland
Zircon U-Pb geochronology places high-temperature geological events into temporal context. Here, we present a comprehensive zircon U-Pb geochronology dataset for the Meso- to Neoarchean Maniitsoq region in sou...
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Oxygen isotopes trace the origins of Earth’s earliest continental crust
Much of the current volume of Earth’s continental crust had formed by the end of the Archaean eon1 (2.5 billion years ago), through melting of hydrated basaltic rocks at depths of approximately 25–50 kilometres, ...
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Open AccessPrecise radiometric age establishes Yarrabubba, Western Australia, as Earth’s oldest recognised meteorite impact structure
The ~70 km-diameter Yarrabubba impact structure in Western Australia is regarded as among Earth’s oldest, but has hitherto lacked precise age constraints. Here we present U–Pb ages for impact-driven shock-recr...
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Zircon oxygen and hafnium isotope decoupling during regional metamorphism: implications for the generation of low δ18O magmas
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 sou...
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Open AccessNo evidence for high-pressure melting of Earth’s crust in the Archean
Much of the present-day volume of Earth’s continental crust had formed by the end of the Archean Eon, 2.5 billion years ago, through the conversion of basaltic (mafic) crust into sodic granite of tonalite, tro...
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An impact melt origin for Earth’s oldest known evolved rocks
Earth’s oldest evolved (felsic) rocks, the 4.02-billion-year-old Idiwhaa gneisses of the Acasta Gneiss Complex, northwest Canada, have compositions that are distinct from the felsic rocks that typify Earth’s a...
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A Palaeoproterozoic tectono-magmatic lull as a potential trigger for the supercontinent cycle
The geologic record exhibits periods of active and quiescent geologic processes, including magmatism, metamorphism and mineralization. This apparent episodicity has been ascribed either to bias in the geologic...
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Correction: Corrigendum: Earth’s first stable continents did not form by subduction
Nature 543, 239–242 (2017); doi:10.1038/nature21383 In this Letter we omitted to cite a paper1 that also used recently developed thermodynamic models2 to predict the melting process in Archaean metabasaltic ro...
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Open AccessContrasting Granite Metallogeny through the Zircon Record: A Case Study from Myanmar
Granitoid-hosted mineral deposits are major global sources of a number of economically important metals. The fundamental controls on magma metal fertility are tectonic setting, the nature of source rocks, and ...
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Earth’s first stable continents did not form by subduction
Phase equilibria modelling of rocks from Western Australia confirms that the ancient continental crust could have formed by multistage melting of basaltic ‘parents’ along high geothermal gradients—a process in...
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Shocked monazite chronometry: integrating microstructural and in situ isotopic age data for determining precise impact ages
Monazite is a robust geochronometer and occurs in a wide range of rock types. Monazite also records shock deformation from meteorite impact but the effects of impact-related microstructures on the U–Th–Pb syst...
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Multi-mineral geochronology: insights into crustal behaviour during exhumation of an orogenic root
Under rare conditions, reworked cratons and their margins preserve the orogenic roots of ancient mountain-building events. However, based on the preservation of high-temperature (~ 800 °C), middle and lower cr...
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Open AccessThe Juvenile Hafnium Isotope Signal as a Record of Supercontinent Cycles
Hf isotope ratios measured in igneous zircon are controlled by magmatic source, which may be linked to tectonic setting. Over the 200–500 Myr periodicity of the supercontinent cycle - the principal geological ...
