Figure F4. Leg 205 Costa Rica drilling area (red box) (Fig. F3) and isochrons derived from seafloor magnetic anomalies (Barckhausen et al., 2001). Numbers indicate crustal age in million years. Tectonic boundaries, convergence direction and rate (arrow) (De Mets et al., 1990), and arc volcanoes (triangles) are shown. FS = Fisher Seamount, QSC = Quesada Sharp Contortion.