A U-TH DATED RECORD OF HOLOCENE SEDIMENTATION IN CREVICE CAVE, MISSOURI

Age constraints were placed on interstratified sediment layers contained within stalagmites using U-Th age dating methods. Stalagmites CC-99-3-B and CC-03-06-B from Crevice Cave, southeastern Missouri were used to constrain Holocene sedimentation events. The sediment layers are mainly silts and are bracketed by calcite fins which protrude from the stalagmite. Each fin was dated to constrain the timing of sedimentation. Nearly 80 ages were obtained representing over 30 sedimentation positions within the two stalagmites.

Stalagmite CC-99-3-B grew periodically from the last interglaciation (~ 130 ka) to the present. The upper 291 cm (~ 75%) of the stalagmite grew during the Holocene. High-precision dating capabilities allow ultra high resolution of individual sedimentation events. For example, age determinations of 1,177 ± 15 and 1,179 ± 19 years b.p. distinguish separate calcite fins. The youngest dated sedimentation event occurred just before 197 ± 7 years b.p. Overall, 15 identifiable fins exist.

Stalagmite CC-03-06-B was collected in active growth position ~ 10 m from CC-99-3-B. It grew exclusively during the Holocene from 5,460 ± 244 years b.p. to the present and is ~ 400 cm in length. Numerous sedimentation events can be correlated by age between the two stalagmites during the late Holocene, possibly revealing common causes for sedimentation.

Further investigation may reveal connections between Holocene climatic and environmental changes of regional scale with cave sedimentation events preserved in the stalagmite record of Crevice Cave. This will broaden the knowledge of local paleoenvironments during the Holocene and potentially develop an understanding of climatic controls on local erosion.