A HIGH-RESOLUTION RECORD OF HOLOCENE EL NIÑO CYCLICITY FROM CREVICE CAVE, MISSOURI

Flood-deposited sediments contained within stalagmites from Crevice Cave, Missouri reveal a correlation between the frequency of El Niño/Southern Oscillation (ENSO) and flooding of the cave throughout most of the Holocene. High-precision U-Th dating of three stalagmites provides a high resolution flooding chronology during the past 8,000 years. Thin clay-rich layers of sediment were deposited on the surface of stalagmites during flood events as flood waters slowly inundated the stalagmites during back-flooding of the cave passage. Stalagmite CC-99-12-B was deposited at the fast average deposition rate of 68 mm per thousand years, and 19 U-Th dates reveal an unusually uniform rate of deposition throughout the past 8,000 years. Millennial-scale cyclicity is apparent in the stalagmite flood record. Furthermore, long-term variability of warm ENSO (El Niño) periods as modeled by Clement et al. (2000) show a close correlation to the flooding frequency recorded in Crevice Cave. In modern times, El Niño increases flooding in southeast Missouri by enhancing moisture transport from the Gulf of Mexico, thereby generating increased storm potential during early winter months. To the best of our knowledge, our record is the most complete and best-dated Holocene record of ENSO behavior for the North American mid-continent. Significance of these correlations may lead to predictions of frequency and magnitude of flooding for periods of warm ENSO-dominated climates.