Improvements in the extraction of microinclusion water from speleothem calcite make possible multiple, higher resolution measurements of dD of water. This can be applied to paleoclimate reconstruction using d¹⁸O and d¹³C of speleothems. Additionally, analysis of lattice-bound water may provide an additional paleothermometer. Two speleothems from Reed's Cave, South Dakota that grew during the Wisconsin glacial period from marine isotope stages 4 to 2 (65 –23 kya) were analyzed to determine the isotopic composition of paleoprecipitation. Paleotemperatures are calculated using O-isotope fractionation between calcite and water. The oxygen isotopes of fluid inclusion water cannot be measured directly because of post-depositional exchange of oxygen molecules between the host calcite and the fluid inclusions. The isotopic compositions of cave dripwaters approximate average annual d¹⁸O and d D of precipitation (Yonge et al .1983), therefore d¹⁸O can be calculated from D/H of inclusion water using the MWL relationship d D=8 d¹⁸O + 10.

FTIR analysis shows that even after removal of microinclusions, a strong water signal still exists. High temperature calcination of calcite to CaO + CO₂ releases this crystal-bound water. Isotopic (D/H) fractionation between bound and inclusion water may yield a paleotemperature record. Also, the presence of this component in water released at high temperatures may explain a -20‰ offset observed by some researchers.