Aierken Yierpan

Abstract Oxygenation of Earth’s oceans and atmosphere through time has consequences for subducted surface signatures that are now stored in the mantle. Here, we report significant mass-dependent selenium isotope variations in modern hot spot–influenced oceanic lavas. These variations are correlated with tracers of mantle source enrichment, which can only be explained by incorporation of abyssal pelagic sediments subducted from a redox-stratified mid-Proterozoic ocean.

Abstract The origin of Earth’s volatiles has been attributed to a late addition of meteoritic material after core–mantle differentiation. The nature and consequences of this ‘late veneer’ are debated, but may be traced by isotopes of the highly siderophile, or iron-loving, and volatile element selenium. Here we present high-precision selenium isotope data for mantle peridotites, from double spike and hydride-generation multicollector inductively coupled plasma mass spectrometry.

The redox-sensitive, chalcophile and volatile Se stable isotope system offers new perspectives to investigate the origin and evolution of terrestrial volatiles and the roles of magmatic and recycling processes in the development of the redox contrast between Earth's reservoirs. Selenium isotope systematics become more robust in a well-constrained petrogenetic context as can be inferred from Se–Te elemental signatures of sulfides and igneous rocks.