The analysis of a speleothem from southwestern Missouri as a methods comparison for stable isotope analyses, and, The potential for paleoclimate inferences without established equilibrium conditions

A speleothem stable isotope record from Hensen Cave, MO was used as a method comparison test. The use of off-line preparation and dual inlet mass spectrometry has been the historically preferred method for speleothem stable isotope analysis. The continuous flow inlet system combined a micromilling apparatus proved to provide the better method precision and a higher sample through-put. For the routine analysis of submilligram sized samples of speleothem carbonate the continuous flow system was found to be preferable isotope ratio mass spectrometer set-up. The two inputs to speleothem carbonate, carbon and oxygen were hypothesized to change on different times. This study attempted to elucidate different periodicity in the two systems using spectral analysis. No difference in the Hensen Cave record could be found. As equilibrium conditions couldn't be proven, the Hensen Cave record is interpreted as being changes in the CO2 dynamics in the subsurface.