title: Platinum-group element abundance patterns in different mantle environments
abstract: Mantle-derived xenoliths from the Cameroon Line and northern Tanzania display differences in their platinum-group element (PGE) abundance patterns. The Cameroon Line lherzolites have uniform PGE patterns indicating a homogeneous upper mantle over several hundreds of kilometers, with approximately chondritic PGE ratios. The PGE patterns of the Tanzanian peridotites are similar to the PGE systematics of ultramafic rocks from ophiolites. The differences can be explained if the northern Tanzanian lithosphere developed in a fluid-rich suprasubduction zone environment, whereas the Cameroon Line lithosphere only experienced melt extraction from anhydrous peridotites.
authors.affiliation: M. Rehkamper, A. N. Halliday, D. Barfod, Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1063, USA. J. G. Fitton and J. B. Dawson, Department of Geology and Geophysics, University of Edinburgh, Edinburgh EH9 3JW, UK.
authors.initials: M
authors.lastname: Rehkamper
authors.initials: AN
authors.lastname: Halliday
authors.initials: D
authors.lastname: Barfod
authors.initials: JG
authors.lastname: Fitton
authors.initials: JB
authors.lastname: Dawson