Figure 3. Variation diagrams illustrating the chemical differences between the pre- and synbreakup succession (open symbols: Site 917 lower, middle, and upper series) on one hand, and the postbreakup oceanic rocks drilled at Sites 915, 918, and 990 (solid symbols) on the other hand. In each plot, the oceanic rocks form a tight, well-defined cluster set apart from the earlier rocks because of their high Sc and relatively low Sr and Ce. The lava flows from Site 989 and the two dikes from Site 917 and 990 clearly have oceanic chemistry. One dike symbol is always hidden by other symbols in the cluster.