Figure F11. Schematic drawings of crustal accretion models (modified from Korenaga and Kelemen, 1998) under discussion with regards to Site 1256. A. Gabbro glacier ductile flow model (e.g., Henstock et al., 1993; Phipps Morgan and Chen, 1993; Quick and Denlinger, 1993). Ductile flow down and outward from a high-level axial magma chamber constructs the lower crust. B. A hybrid model of ductile flow with sill intrusions (e.g., Boudier et al., 1996). C. "Sheeted" or "stacked" sill model of in situ formation of the lower crust by on-axis sill intrusions (e.g., Bédard et al., 1988; Kelemen and Aharonov, 1998; Kelemen et al., 1997; MacLeod and Yoauancq, 2000).
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