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Construction of the Yilgarn Craton over 1.5 billion years

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Created 20/01/2025

Updated 20/01/2025

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The Yilgarn Craton of Western Australia represents one of the largest pieces of Precambrian crust on Earth, and a key repository of information on the Meso-Neoarchean period. Understanding the crustal, tectonic, thermal, and chemical evolution of the craton is critical in placing these events into an accurate geological context, as well as developing holistic tectonic models for the Archean Earth. In this study, we collected a large U-Pb (420 collated samples) and Hf isotopic (2163 analyses) dataset on zircon to investigate the evolution of the craton. These data provide strong evidence for a Hadean-Eoarchean origin for the Yilgarn Craton from mafic crust at ca. 4000 Ma. This ancient cratonic nucleus was subsequently rifted, expanded and reworked by successive crustal growth events at ca. 3700 Ma, ca. 3300 Ma, 3000-2900 Ma, 2825-2800 Ma, and ca. 2730-2620 Ma. The <3050 Ma crustal growth events correlate broadly with known komatiite events, and patterns of craton evolution, revealed by Hf isotope time-slice mapping, image the periodic break-up of the Yilgarn proto-continent and the formation of rift-zones between the older crustal blocks. Crustal growth and new magmatic pulses were focused into these zones and at craton margins, resulting in continent growth via internal (rift-enabled) expansion, and peripheral (crustal extraction at craton margins) magmatism. Consequently, we interpret these major geodynamic processes to be analogous to plume-lid tectonics, where the majority of tonalite-trondhjemite-granodiorite (TTG) felsic crust, and later granitic crust, was formed by reworking of hydrated mafic rocks and TTGs, respectively, via a combination of infracrustal and/or drip-tectonic settings. While this process of crust formation and evolution is not necessarily restricted to a specific geodynamic system, we find limited direct evidence that subduction-like processes formed a major tectonic component, aside from re-docking the Narryer Terrane to the craton at ca. 2740 Ma. Overall, these 'rift-expansion' and 'craton margin' crustal growth process led to an intra-cratonic architecture of younger, juvenile terranes located internal and external to older, long-lived, reworked crustal blocks. This framework provided pathways that localized later magmas and fluids, driving the exceptional mineral endowment of the Yilgarn Craton. This Abstract/Poster was submitted to & presented at the 2023 6th International Archean Symposium (6IAS) 25 - 27 July (https://6ias.org/)

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Title Construction of the Yilgarn Craton over 1.5 billion years
Language eng
Licence notspecified
Landing Page https://devweb.dga.links.com.au/data/dataset/cc2eaa8f-c961-4bd6-8fdd-f6ddbd9b4d18
Contact Point
Geoscience Australia
clientservices@ga.gov.au
Reference Period 14/09/2023
Geospatial Coverage {"type": "Polygon", "coordinates": [[[113.0, -36.0], [129.0, -36.0], [129.0, -14.0], [113.0, -14.0], [113.0, -36.0]]]}
Data Portal data.gov.au

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This dataset was originally found on data.gov.au "Construction of the Yilgarn Craton over 1.5 billion years". Please visit the source to access the original metadata of the dataset:
https://devweb.dga.links.com.au/data/dataset/construction-of-the-yilgarn-craton-over-1-5-billion-years

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