Geophysical data collected as part of Leg 37 are compiled with more recent data collected for new IPOD drilling site surveys. Bathymetric and magnetic maps covering the area of sites 332–335 are presented. On the basis of magnetic anomaly correlations it is suggested that site 334 is on normal crust between fracture zones A and B and not closer than 15 km to either fracture zone. Magnetic anomaly inversion is applied to a composite profile, extending from the ridge crest out to beyond anomaly 5. It shows a definite change in spreading rate at 4.7 ± 0.5 Ma. Average rates for the periods 0–4.7 Ma and 4.7–10 Ma are 10.2 ± 0.9 mm/yr and 14.0 ± 1.9 mm/yr respectively. The inversion results are consistent with a simple magnetic source layer 2 km thick.

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