Subduction zone Hf-anomalies: Mantle messenger, melting artefact or crustal process?
Jon Woodhead, Janet Hergt, Alan Greig, Louise Edwards
EARTH AND PLANETARY SCIENCE LETTERS | ELSEVIER | Published : 2011
The origin of Hf elemental depletions in subduction zone magmas is investigated using new major- and trace-element data for cumulate xenoliths from the Mariana arc, and deep sea sediments recovered by the DSDP and ODP drilling programmes. Results indicate that most of the rare earth element (REE) and Hf inventory in the xenoliths is contained within two minerals-clinopyroxene and titanomagnetite-and that removal of a typical gabbroic fractionating assemblage reduces the depletion in Hf relative to neighbouring REE on a mantle normalised trace element diagram (commonly denoted Hf/Hf*) in the evolving magmas. Confirmation of this observation is provided by a variety of literature data from dif..View full abstract