Long-lasting formation and metamorphic alteration of Paleoarchean (~3.3 Ga) peridotite bodies within the Eoarchean Itsaq Gneiss Complex, southwest Greenland

The Earth’s origin and early evolution are crucial for the formation of habitability and the emergence of life (Anbar, 2001), and have been hotly debated. Nonetheless, our understanding of Earth’s early history is impeded by the scarcity of early geological records. The most ancient Hadean traces are found in zircons from the Jack Hills (Wilde et al., 2001), while Eoarchean rocks are sparsely dispersed in several locations (e.g., Acasta and Labrador in Canada and Itsaq Gneiss Complex in southwest Greenland; Bridgwater & Schiøtte, 1991; Nutman et al., 1996; Bowring & Williams, 1999). Among these identified Eoarchean rocks, the Itsaq Gneiss Complex (IGC) stands out as the best-preserved and largest (~3000 km2) occurrence (Nutman et al., 1996), and provides a unique glimpse into the Earth’s Eoarchean and earlier history. In this regard, the ultramafic rocks of the IGC, which includes the Isua Supracrustal Belt (ISB), south of ISB (SOISB), Narssaq ultramafic body (NUB) and Ujaragssuit Nunât ultramafic complex (hereafter UNUC) and so on, have been the focus of scientific inquiry for decades. Previous studies on these ultramafic rocks have helped to delineate the scope of late accretion, including the mixing extent of late accretionary materials in the Eoarchean (Bennett et al., 2002; Willbold et al., 2011; Rizo et al., 2016; Creech et al., 2017; Dale et al., 2017; van de Löcht et al., 2018; Xu et al., 2023) and the origin of these building blocks (Fischer-Gödde et al., 2020), based on evidence from highly siderophile elements and their embedded long- and short-lived radioactive, stable and nucleosynthetic isotope systems.