Subduction pelagic sediment

Lead isotopes. Sato and Sasaki (1973) concluded on the basis of a remarkable narrow range in lead isotopic composition of Kuroko ores that lead of Kuroko ore came from deep-seated source which originated from subducting pelagic sediments. 

In basalts, lawsonite is the only hydrous phase which is stable in the deep mantle and this phase dehydrates at the depth of the mantle transition zone. Similarly in subducted pelagic sediments there is a series of hydrated aluminum silicates and oxides (including the phase Egg - AlSiOs.OH) which also remain stable down to transition zone depths (Williams Hemley, 2001). 

Hole MJ, Saunders AD, Marriner GF, Tamey J (1984) Subduction of pelagic sediments implications for the origin of Ce-anomalous basalts from the Mariana islands. J Geol Soc London 141 453-472 Holland HD (1984) The Chemical Evolution of the Atmosphere and Oceans. Princeton Uiuversity Press, Princeton... 

Newman S, Macdougall JD, Finkel RC (1986) Petrogenesis and °Th- U disequilibrium at Mt. Shasta, Califonua, and in the Cascades. Contrib Mineral Petrol 93 195-206 Nichols GT, Wylhe PJ Stem CR (1994) Subduction zone melting of pelagic sediments constrained by melting experiments. Nature 371 785-788... 

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