Figure 4. Sketch showing the relationship of the site locations to the various characteristic features of the OCT in the Iberia Abyssal Plain. Thick lines bind the three main types of crust identified in the OCT. Triangles mark the trend of the peridotite ridge, proposed from seismic reflection profiles by Beslier et al. (1993). Thinner bold lines mark the positions of seafloor spreading magnetic anomalies J and M0, chosen from a reduced-to-the-pole magnetic anomaly contour chart (S.R. Srivastava, pers. comm., 1993) and the eastern edge M3(E) of the magnetic block used in a two-dimensional seafloor spreading model to model anomaly M3. Thin lines are seismic refraction profiles reported by Whitmarsh, Miles, and Mauffret (1990).