Figure F11. Depth variation of eight elements determined by XRF powder analysis on either side of the unconformity (Section 316-C0004C-9H-5). Covariations between Ca, Mg, and Mn suggest these elements reflect changes in the calcite fraction. Variations in Fe and S reflect abundant pyrite at the unconformity, whereas covariations in Al, Si, and Ti may reflect complementary reductions in these elements as a consequence of relative pyrite abundance. Covariation between Ca and Mn as seen in the crossplot (lower right) may have implications for understanding the trend of diminishing carbonate in calcareous mudstones above the unconformity.
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