North-Central - 52nd Annual Meeting

Paper No. 1-4
Presentation Time: 9:00 AM

A HIGH-RESOLUTION RECORD OF FLOODING FROM CREVICE CAVE, MISSOURI DURING THE TIME OF MARINE ISOTOPE STAGE 5


DORALE, Jeffrey A., Dept. of Earth and Environmental Sciences, University of Iowa, 115 Trowbridge Hall, Iowa City, IA 52242-1379

Shallow ground water flow in Crevice Cave, Missouri is regulated by numerous recharge points along with a very limited number of outlets, which can create a condition of slow back flooding during high recharge events. Detrital particles may become suspended during the flooding and get deposited on speleothem and bedrock surfaces that are inundated by the flooding. After flood waters recede, thin clay-rich deposits may be preserved by the subsequent resumption of speleothem growth, essentially confining the deposits in calcite.

High-precision U-Th dating of a stalagmite from Crevice Cave provides a high-resolution flooding chronology during the period from 112,000 to 74,000 years ago, which captures most of MIS 5d/5c/5b/5a sequence. Strong contrasts in low frequency versus high frequency flooding regimes are observable in the record, and suggest there are prominent cycles of heavy midwestern precipitation behavior that are part of the larger climatic changes of the past interglacial.