Os Isotopic and Platinum Group Element (PGE) Geochemistry of Oceanic Mantle: A Case Study from the Oman Ophiolite

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Recommended project is for measurement of the platinum group elements (PGE), chalcophile elements, and Os isotopic compositions on well-characterized dunites and harzburgites from the Oman ophiolite, representing relict samples from obducted oceanic mantle. The major goal is to determine the Os isotopic and PGE composition of the mid-ocean ridge basalt (MORB) mantle source, principally to test whether it has chondritic Os and PGE signatures that are fractionated from chondrites (as are abyssal and massif peridotites). The proposal will also examine PGE mobility during magmatic and alteration processes, considering specifically whether wall-rock interaction during melt transport and weathering of exposed rock can change PGE values. This work will provide important constraints regarding the origin of the MORB source, and should help to resolve geochemical contraditions presented between ophiolites and abyssal peridotites regarding whether they are both residues of MORB melting.