Where is Gadolinium in sea-floor sediments?

As part of the ERC project DEEP-SEE (collaboration with Alain Manceau), the next chapter of the incorporation of rare earth elements in apatites from the sea floor is now published in Environmental Science: Nano. It turns out that Gadolinium is not associated with cerium in a phosphate rich precipitate, but rather present in the amorphous layer surrounding apatite, similar to yttrium. Indeed, computations evidence that a medium-range distance (about 6.2 Å; just out of reach for EXAFS detection) between Gd and/or Y atoms leads to the most stable aggregate.