Map of magnetic anomaly numbers Deep Sea Drilling sites

magnetic anomaly number Age (Ma) from geomagnetic reversal chronology extrapolated in South Atlantic assuming constant rate of spreading paleontological age, Ma Seafloor ages from deep sea drilling versus geomagnetic reversal chronology Deep sea drilling in the South Atlantic Ocean

Chronology of geomagnetic field reversals magnetic anomaly “number” Ocean floor age, millions of years (Ma), determined largely from deep sea drilling

Geologic time scale My 600 My Age range of modern ocean floor

Transform faults

South Atlantic Ocean

South Atlantic Ocean inactive fracture zone active transform fault active ridge crest

inactive fracture zone active transform fault active ridge crest inactive fracture zone

Transform faults and fracture zones

Map pattern of magnetic anomaly number Deep sea drilling calibration of chronology of geomagnetic field reversals back to 180 Ma. Map pattern of ocean floor age

anomaly no M16 M10N M4M0M21M Age of ocean floor From Muller, et al., 1997