Figure F1. 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. B. Range is from about 60 (red) to +45 (pink) Mgal south of the 15°20'N Fracture Zone. 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.
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