Convective isolation of Hadean mantle reservoirs through Archean time
Jonas Tusch, Carsten Münker, Eric Hasenstab, Mike W. Jansen, Chris S. Marien, Florian Kurzweil, Martin J. Van Kranendonk, Hugh Smithies, Wolfgang D. Maier, Dieter Garbe‐Schönberg
Abstract
Significance Geological processes like mantle convection or plate tectonics are an essential factor controlling Earth’s habitability. Our study provides insights into timescales of convective homogenization of Earth’s early mantle, employing the novel tool of high-precision 182 W isotope measurements to rocks from the Pilbara Craton in Australia, that span an age range from 3.5 billion years to 2.7 billion years. Previous 182 W studies mostly covered snapshots through geologic time, so the long-term 182 W evolution of the mantle has been ambiguous. Together with sophisticated trace element approaches, we can now provide an improved insight into such timescales, arguing for local preservation of primordial geochemical heterogeneities within Earth’s mantle as late as around 3.0 billion years, the putative onset of widespread plate tectonics on Earth.