Recycled crust in the upper mantle: insights from combining isotopic data and geodynamics Kari M. Cooper, UC Davis (collaboration with John M. Eiler, Caltech, Kenneth W.W. Sims, WHOI, Charles H. Langmuir, Harvard, Louise Kellogg, UCD)

CIDER 2006: Mixing in the mantle CIDER group: Stan Hart, Louise Kellogg, Liz Vanacore, Amber Harris, Julie Prytulak AGU poster 2006 Oxygen isotopes and radiogenic isotopes in MORB

Hunt & Kellogg, 2001 Sampling mantle heterogeneities Kellogg et al., 2002 Brandenburg & van Keken, 2007

Oxygen isotope composition of MORB Harmon&Hoefs, 1995; Eiler, 2001 Cooper et al. in prep (see poster) Correlations between laser data for  18 O and other geochemical indices Major element: ‘buffered’ composition Balanced by strong isotopic contrasts between crust and mantle Mixing relations relatively simple to define

 18 O in MORB by ocean basin Oxygen isotopes have the same distribution in each ocean basin. How faithfully does the normal distribution of data record mantle variations? What are the implications for the physical distribution and sampling of upper mantle heterogeneities?  = 5.52  = 0.10  = 5.52  = 0.11  = 5.49  = 0.10

Monte Carlo simulations How much of the variance can be attributed to analytical error and to small sample size?

Summary and future directions Distribution of  18 O-enriched domains in upper mantle is the similar beneath all ocean basins Next step: comparison with geodynamic simulations - implications of observed distribution Forum like CIDER is important in developing broad thinking about a specific problem