A persistent Hadean–Eoarchean protocrust in the western Yilgarn Craton, Western Australia

Abstract

The scarcity of well-preserved primary Hadean-Eoarchean material (e.g. Goodwin, 1996) impedes understanding of Earth's earliest continental crust. However, the geochemical legacy of ancient (>3,800 Ma) crustal seeds may survive reworking, conveying information on early crust-mantle differentiation into younger continental crust and ultimately the detrital record (Griffin, Belousova, Shee, Pearson, & O 'Reilly, 2004;Guitreau et al., 2019). The Archean Yilgarn Craton (YC) in Western Australia (Figure 1a) has enabled significant advances in the understanding of the spatial and temporal development of early Earth's crust (e.g. Cassidy et al., 2006). The Narryer Terrane, in the northwestern YC, preserves some of the oldest continental crust on the planet (>3,700 Ma; Kinny, Williams,

Cryptic geological histories accessed through entombed and matrix geochronometers in dykes

“…However, based on the current data it is impossible to distinguish between inheritance of sedimentary or magmatic material into the dyke. Furthermore, detrital zircon U-Pb data in beach sediments in SW Australia have yielded additional putative evidence for Paleoarchean crust, with two c. 3500 Ma grains found 28 . In any case, the c. 3440 Ma inherited component reported herein supports an interpretation of ancient >3000 Ma components within the South West Terrane (Fig.…”

“…A common ancient substrate in the western margin of the Yilgarn craton has been proposed based on Hf depleted mantle model ages from detrital zircon grains 28 . The identification of a Paleoarchean inherited zircon component provides additional evidence for a connection between the South West Terrane and crustal ages with similarity to the Narryer Terrane.…”

“…These rocks commonly contain Meso-to Paleoarchean detrital zircons, with only a single Eoarchean detrital zircon dated at 3676 ± 12 Ma 14 . Unradiogenic Lu-Hf data measured from detrital zircon grains from modern beaches of southwestern Australia also suggest the presence of isotopically coherent Hadean-Eoarchean crustal vestiges associated with the southwestern border of the Yilgarn Craton 28 .…”