Figure 3. A. Conceptual model of the OCT off western Iberia. East-dipping hachured symbols indicate thinned continental crust; west-dipping hachured symbols indicate oceanic crust; the cross-hachured region indicates transitional and relatively highly magnetized, but nonoceanic, crust (see text). The light gray layer beneath the OCT represents either serpentinized peridotite or material affected by underplating. Densities (Mg · m³) are indicated for each layer. L1, L2, and so forth, are seismic refraction lines reported by Whitmarsh, Miles, and Mauffet (1990). IAP-2, IAP-3C, and so forth, are the proposed Leg 149 drill sites; sites in square brackets have been projected onto the east-west profile. B. A gravity profile (continuous line) computed with the densities and model given in (A). Crosses represent observations (Whitmarsh et al., 1993).