Characterization and Correction of Evaporative Artifacts in Speleothem Fluid Inclusion Isotope Analyses as Applied to a Stalagmite From Borneo

Fluid inclusion water isotope measurements in speleothems have great potential for paleoclimate studies as they enable the reconstruction of precipitation dynamics and land temperatures. Several previous observations, however, suggest that waters do not always reflect isotopic composition surface precipitation. In such cases, dripwaters are thought to be modified by evaporation cave environment results more positive δ2H δ18O values shallow δ2H/δ18O slopes. Although can occur systems, also lost during analysis but before extraction. Here, we examine likelihood this possibility with a stalagmite from Borneo. We demonstrate many samples lose water, loss is controlled type size inclusions. With multiple replicate coeval samples, calculate an evaporative slope 1.0 ± 0.6 (2SE). This value consistent model predictions fractionation at high analytical temperature low humidity. Finally, propose method correct effect. find fluid–calcite paleotemperatures calculated corrected data show excellent agreement recent microthermometry estimates Borneo, supporting validity our approach implying limited disequilibrium variations. Corrected fluid follow expected hydroclimate response Borneo periods reduced Atlantic Ocean meridional overturning circulation. Our careful petrographic examination necessary reliable reconstructions speleothem isotopes.