The mid-Miocene climatic optimum (17-14 million years ago) and subsequent cooling is an important global climate event that affected the North American continental interior’s temperatures, ecosystems, and hydrology. These effects can be studied using isotopic records of surface temperature and hydrologic conditions from 16 to 6 million-year-old lake minerals (carbonate) on the southern Colorado Plateau–the Bidahochi Formation. Lake carbonate bulk isotopic values measure the abundance of heavy to light carbon and oxygen isotopes (d13C and d18O), and clumped analysis (∆47, ∆48) examines the bonding of heavy isotopes that reflect carbonate growth temperatures. However, the temperature estimates derived from clumped isotope data (T∆47 and T∆48) assume mineral growth under isotopic equilibrium, which may not be true for all lake samples. Disagreement of apparent temperatures T∆47 and T∆48 and covariance with d13C and d18O values can assess non-equilibrium. In cases where carbonates precipitated out of equilibrium, applying both ∆47 and ∆48 data (dual-clumped isotope thermometry), and using models to understand the mechanism for disequilibrium (e.g., kinetic isotope effects) allows for the reconstruction of true growth temperature. Here we analyze different types of lake carbonates using sample textures and d13C, d18O, ∆47, and ∆48 covariance to determine if they grew in or out of kinetic equilibrium and reconstruct depositional temperatures. Preliminary results support the hypothesis that lake carbonates that formed at the surface and settled into deeper water (marls) precipitated in equilibrium and recorded accurate temperatures, while carbonates formed at lake margins affected by groundwater (tufas) grew quickly and may have experienced kinetic effects that require dual-clumped analysis to reconstruct their growth temperatures. The temperature record that we build using ∆47 and ∆48 data will give a data set of surface temperatures in the North American continental interior throughout the mid-Miocene climatic optimum further constraining paleoclimate records.