Comparatively little is known about the evolution of the terrestrial mantle throughout the Hadean and Early Archean, after four and a half billion years of Earth history erasing its primordial features. Whilst there are vestiges of Hadean material preserved as zircons and other xenocrysts in rocks of Archean age, recently, insight into the Hadean-Archean mantle has instead derived from studying small but significant variations present amongst short-lived radiogenic isotopes.
The half life of the parental isotope in the Hf-W system (8.9 Ma for 182Hf) requires that any heterogeneity that exists, irregardless of the age of the sample, ultimately derives from processes operating within the first ca. 60 Ma of Earth history. For my PhD I will be studying heterogeneity in 182W, the decay product of 182Hf, in rocks of primarily Archean age. From this I hope to gain insight into some of the most geochemically and geodynamically important phases in Earth history, such as the timing and admixing of the "late veneer" into the silicate Earth, early terrestrial mantle differentiation, and even the timing of the onset of modern-style plate tectonics.
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