Rehkamper M, Halliday AN, Barfod D, Fitton JG, Dawson JB
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.
Science. 1997 Nov 28;278(5343):1595-8. doi: 10.1126/science.278.5343.1595.
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.
来自喀麦隆线和坦桑尼亚北部的地幔衍生捕虏体在铂族元素（PGE）丰度模式上存在差异。喀麦隆线的二辉橄榄岩具有均匀的PGE模式，表明在数百公里范围内上地幔是均匀的，PGE比值近似于球粒陨石。坦桑尼亚橄榄岩的PGE模式与蛇绿岩中超镁铁岩的PGE系统相似。如果坦桑尼亚北部岩石圈是在富含流体的超俯冲带环境中形成的，而喀麦隆线岩石圈仅经历了无水橄榄岩的熔体提取，那么这些差异就可以得到解释。
