Figure F1. Preliminary calculation of Mantle Bouger Anomaly (e.g., Lin et al., 1990) from shipboard gravity measurements in 1998 (Kelemen et al., 1998b; Matsumoto et al., 1998; Casey et al., 1998). Both figures use the same range of colors, representing slightly different values. A. Range is from about –35 (red) to +40 (pink) Mgal north of the 15°20'N FZ. B. Range is from about –60 (red) to +45 (pink) Mgal south of the 15°20'N FZ. These data suggest that the magma-starved region with abundant peridotite outcrops from 14°40' to 15°40'N lies on the periphery of large magmatic segments centered at ~14° and 16°N, with thick igneous crust in the segment centers.