title: Archean komatiite volcanism controlled by the evolution of early continents.
abstract: The generation and evolution of Earth's continental crust has played a fundamental role in the development of the planet. Its formation modified the composition of the mantle, contributed to the establishment of the atmosphere, and led to the creation of ecological niches important for early life. Here we show that in the Archean, the formation and stabilization of continents also controlled the location, geochemistry, and volcanology of the hottest preserved lavas on Earth: komatiites. These magmas typically represent 50-30% partial melting of the mantle and subsequently record important information on the thermal and chemical evolution of the Archean-Proterozoic Earth. As a result, it is vital to constrain and understand the processes that govern their localization and emplacement. Here, we combined Lu-Hf isotopes and U-Pb geochronology to map the four-dimensional evolution of the Yilgarn Craton, Western Australia, and reveal the progressive development of an Archean microcontinent. Our results show that in the early Earth, relatively small crustal blocks, analogous to modern microplates, progressively amalgamated to form larger continental masses, and eventually the first cratons. This cratonization process drove the hottest and most voluminous komatiite eruptions to the edge of established continental blocks. The dynamic evolution of the early continents thus directly influenced the addition of deep mantle material to the Archean crust, oceans, and atmosphere, while also providing a fundamental control on the distribution of major magmatic ore deposits.
authors: Centre for Exploration Targeting, Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, School of Earth and Environment, University of Western Australia, Perth, WA 6009, Australia;Department of Applied Geology, Curtin University, Bentley, WA 6102, Australia; david.mole@csiro.au.
authors: David R
authors: DR
authors: Mole
authors: Centre for Exploration Targeting, Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, School of Earth and Environment, University of Western Australia, Perth, WA 6009, Australia;
authors: Marco L
authors: ML
authors: Fiorentini
authors: Centre for Exploration Targeting, Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, School of Earth and Environment, University of Western Australia, Perth, WA 6009, Australia;
authors: Nicolas
authors: N
authors: Thebaud
authors: Centre for Exploration Targeting, Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, School of Earth and Environment, University of Western Australia, Perth, WA 6009, Australia;
authors: Kevin F
authors: KF
authors: Cassidy
authors: Centre for Exploration Targeting, Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, School of Earth and Environment, University of Western Australia, Perth, WA 6009, Australia;
authors: T Campbell
authors: TC
authors: McCuaig
authors: Geological Survey of Western Australia, Department of Mines and Petroleum, East Perth, WA 6004, Australia;
authors: Christopher L
authors: CL
authors: Kirkland
authors: Geological Survey of Western Australia, Department of Mines and Petroleum, East Perth, WA 6004, Australia;
authors: Sandra S
authors: SS
authors: Romano
authors: Centre for Exploration Targeting, Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, School of Earth and Environment, University of Western Australia, Perth, WA 6009, Australia;Geological Survey of Western Australia, Department of Mines and Petroleum, East Perth, WA 6004, Australia;
authors: Michael P
authors: MP
authors: Doublier
authors: Key Centre for the Geochemical Evolution and Metallogeny of Continents, Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, Macquarie University, North Ryde NSW 2109, Australia; and.
authors: Elena A
authors: EA
authors: Belousova
authors: Earth Science and Resource Engineering, Commonwealth Scientific and Industrial Research Organization (CSIRO), Kensington, Perth, WA 6151, Australia.
authors: Stephen J
authors: SJ
authors: Barnes
authors: Centre for Exploration Targeting, Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, School of Earth and Environment, University of Western Australia, Perth, WA 6009, Australia;
authors: John
authors: J
authors: Miller
mesh_terms: D001105:Archaea / Q000502:physiology*; D005075:Biological Evolution; D005580:Fossils; D018707:Volcanic Eruptions
keywords: Ni-Cu-PGE deposits; architecture; crustal evolution; lithosphere; mantle plumes