Nd and Sr isotope evidence linking mid-ocean-ridge basalts and abyssal peridotites
Peridotites found on the sea floor are widely believed to be residues left by mid-ocean-ridge basalt (MORE) melting. As such, their composition should provide insights into the nature of the sub-oceanic depleted mantle. But although these abyssal peridotites occur in mid-ocean ridge fracture zones 1,2, there is little other evidence in support of their genetic link with MORB, and doubts about it have been raised3-5. Radiogenic isotopes should be able to provide a powerful test of the hypothesis, but previous studies3,8-10 on whole rocks have not provided unambiguous answers as they are generally altered by sea water. Here we present measurements of the Nd and Sr isotope compositions of a suite of abyssal peridotite clinopyroxenes which should have resisted alteration. Despite residual seawater contamination of Sr in the clinopyroxenes, the data demonstrate that the peridotites are from a depleted mantle source, identical to that of MORB. This provides a strong indication that abyssal peridotites are residues of MORB melting. © 2002 Nature Publishing Group.
Publication Source (Journal or Book title)
Snow, J., Hart, S., & Dick, H. (1994). Nd and Sr isotope evidence linking mid-ocean-ridge basalts and abyssal peridotites. Nature, 371 (6492), 57-60. https://doi.org/10.1038/371057a0