I use stable isotopes to investigate water-rock interaction, crustal recycling, and near-surface conditions on the early Earth. In this part of my work, the key question is how much primary environmental information remains preserved in ancient rocks that have been hydrothermally altered and later metamorphosed. Instead of treating Archean isotope records as automatically compromised, I focus on separating the signatures of early exchange from those of later overprint.
My recent work in this area has centred on triple oxygen and hydrogen isotopes in 3.8 Ga metalavas from the Saglek-Hebron terrane. The purpose is to understand seawater-oceanic crust interaction in the Eoarchean and to evaluate how alteration and metamorphic dehydration affect the isotope record of very old submarine volcanic rocks. Triple oxygen isotopes are especially useful because they allow a more rigorous view of fluid source and exchange history than conventional oxygen isotope measurements alone. I combine isotope data with petrological reasoning and modelling so that the isotope record is interpreted within the full metamorphic and alteration history of the rock. More broadly, this work is part of my interest in how altered mafic rocks can still preserve information about ancient hydrosphere-crust interaction and, by extension, the evolving surface environment of the early Earth.
