Figure 4. Correlation between Ba flux in subducted sediment and Ba enrichment of arc basalts for various arcs (Ant = Northern Antilles, Mar = Mariana, T= Tonga, Mex = Mexico, J = Java, Al = Aleutians, and G = Guatemala) around the world (after Plank and Langmuir, 1993). Open circles = three different sediment flux estimates for the Mariana, based on the three ODP Sites drilled during Leg 129 (800-802) (Plank and Langmuir, 1998). Although there are variations from site to site, the average sediment input to the Mariana is fairly well constrained (± 20%). Note Izu volcanics are lower in Ba/Na than Mariana volcanics by a factor of two. B. Contrasting Pb isotopic composition of Mariana (open circle) and Izu-Bonin (solid circle) arc volcanics. Mariana volcanics form a mixing trend (arrow), almost perfectly coincident with mixtures of ODP Hole 801C sediment (open boxes) and basalt (solid boxes) averages.

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