Figure F3. Preliminary calculation of Mantle Bouger Anomaly (e.g., Lin et al., 1990) from shipboard gravity measurements taken in 1998 (Kelemen et al., 1998a; 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 Fracture Zone (FZ). B. Range is from about –60 (red) to +45 (pink) mgal south of the 15°20´N Fracture Zone. These data suggest that the 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 (also see Escartin and Cannat, 1999, and Fujiwara et al., 2003).

Figure F3. Preliminary calculation of Mantle Bouger Anomaly (e.g., Lin et al., 1990) from shipboard gravity measurements taken in 1998 (Kelemen et al., 1998a; 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 Fracture Zone (FZ). B. Range is from about –60 (red) to +45 (pink) mgal south of the 15°20´N Fracture Zone. These data suggest that the 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 (also see Escartin and Cannat, 1999, and Fujiwara et al., 2003).