Resumen de Variation of Late Mastrichtian planktic foraminiferal faunas from rhythmically bedded sediments.
Late Maastrichtian planktic foraminifera from rhythmically bedded sections were studied quantitatively, to determine the extent of faunal variation at the scale of orbital cycles. Variation in foraminiferal concentrations and fragmentation at Site 516 is consistent with levels of dissolution that varied with precession cycles. Although the carbonates are diagenetically altered, dissolution cycles are interpreted as primary. Results for Site 605 are inconclusive, but variation in carbonate content could represent dissolution as well. Two land sections near El Kef, Tunisia, and Bidart, France, show weak variation in planktic foraminiferal faunal composition, indicating that cylic variation in carbonate content is mainly the result of dilution by variable clay accumulation rates.
