Search for: All records

Stalagmites are an important archive of terrestrial climate information. However, there remains questions about the ability of stalagmites to form in oxygen isotopic equilibrium and thus record, in a simple manner, the oxygen isotopic composition and temperature of formational fluids. Recent studies have suggested that the combined application of 48 and 47 carbonate clumped isotope measurements can quantify the extent of kinetic isotope fractionation in stalagmites and thus used to correct for these kinetic isotope effects and solve for the original formation temperatures. Here we measure the 47 and 48 values from 16 different samples of the same stalagmite from central California that spans the deglaciation (11 to 20 kya). Each sample is replicated three to five times. We find that based on these measurements the extent of kinetic fractionation present in the carbonate from this stalagmite is minimal. The temperature calculated from 47 in this stalagmite ranges from 11.6 to 19.9 °C, in agreement with regional reconstructions of temperatures from 47 values of lake carbonates. In contrast, previously published the 18O and 2H values of inclusion fluids (Wortham et al., 2022) from this stalagmite suggest periods of increasing kinetic fractionation of the water isotopes at 13 and 15 ka. These periods have been previously interpreted to be times of a reduction in effective moisture regionally. We suggest by this comparison that the use of both water isotopes and the dual clumped isotope system in stalagmites can aide the interpretation of where kinetic fractionation occurs in the hydrologic and carbonate precipitation system in caves. We will discuss the work’s implications for paleoclimate records from stalagmites and other terrestrial systems in seasonally dry and Mediterranean regions.