Paper alert – Molybdenum isotopes in basalts, and potential constraints on the redox state of subducted slabs
It's fresh off the press, Qasid Ahmad and co-authors (including yours truly) just published a short paper at GPL (here) providing some constraints on the redox state of subducted slabs, using molybdenum isotopes. And yes, articles in Geochemical Perspective Letters are fully open-access, thanks to the EAG support.
Qasid's paper is titled "Molybdenum isotopes in plume-influenced MORBs reveal recycling of ancient anoxic sediments"
Using this new work to re-activate this page, but note that i've posted a short thread on twitter, check it out below.
How do molybdenum isotope constrain the redox state of subducted slabs? Qasid Ahmad just published a short paper providing some constraints. Fully open access thanks to @EAG_. Quick thread https://t.co/QEQc4HfhjN— Jabrane Labidi (@JabraneLabidi) October 20, 2022
The studied objects here are basalts dredged up on the South-Atlantic mid-ocean ridge. These basalts record well-known interactions between the sub-oceanic mantle and plume-derived components, delivered to the ridge by both the Shona and the Discovery hotspots.
The new finding in this work is the observation of correlations between Mo stable isotopes and radiogenic isotope tracers such as Nd and Sr isotopes.
For those who would want to learn more, these trends were already observed in 2013 and in 2020 for sulfur and selenium isotopes in the very same samples. Nice to see it further confirmed with molybdenum!
Now and that's the coolest part of the paper: the recycled sediment does not appear to be fractionated compared to the un-subducted protoliths. The data can easily be satisfied with sediments observed at the surface of the Earth (i.e. that never were obliterated by subduction). It's as if the recycled sediments underwent no Mo isotope fractionation.