Modern mantle-like μ182W signatures in Paleoarchean rocks from southern India

The isotope records of short lived ¹⁸²Hf-¹⁸²W and ¹⁴⁶Sm-¹⁴²Nd decay systems preserved in Archean crustal rocks that formed from different mantle domains, provide temporal constraints on chemical differentiation processes on Earth during the Hadean eon (>4.0 Ga). These early differentiation events provide potential insights on the geodynamic environment prevailing during the formation of the first continents. We present a μ¹⁸²W-stable W isotope data set for felsic and mafic-komatiitic suites (∼3.4–3.0 Ga) from the western Dharwar Craton in India previously analysed for their μ142Nd. As one of the oldest cratonic areas on Earth, it preserves key evidence for an incomplete convection and mixing of the Hadean mantle. The results reveal μ1¹⁸²W values resembling that of the modern Earth’s upper mantle. In contrast, their anomalous ¹⁴²Nd isotope compositions requires Sm/Nd fractionation before 4.0 Ga. This implies that the mantle source differentiated only after ¹⁸²Hf became extinct (