Spatial and Temporal Variability in the Geochemistry of Basalts from the East Pacific Rise

Closely spaced sampling of basalts around the East Pacific Rise, made possible by a new sampling technique, reveals spatial patterns of change in the composition of the sea floor. The patterns demonstrate the scale and magnitude of temporal variability in the basalt chemistry, and suggest that the characteristic length scale of petrological segmentation can vary over time from 15 to >40 km along a single section of ridge. Patterns of basalt composition on the sea floor reveal the history of the ocean ridge with much finer resolution than do sea-floor spreading magnetic anomalies.