Element fluxes associated with subduction related magmatism

Abstract

Destructive plate margin magmas may be subdivided into two groups on the basis of their rare earth element (REE) ratios. Most island arc suites have low Ce/Yb, and remarkably restricted isotope ratios of 87Sr/86Sr=0.7033, 143Nd/144Nd=0.51302, 206Pb/ 204Pb=18.76, 207Pb/204Pb=15.57, and 208Pb/204Pb=38.4. However, they also have Rb/Sr (0.03), Th/U (2.2) and Ce/Yb (8.5) ratios which are significantly less than accepted estimates for the bulk continental crust. The high Ce/Yb suites have higher incompatible element contents, more restricted heavy REE, and much more variable isotope ratios. It is argued that for isotope and trace element models the slab component can usefully be taken to consist o..