LAUSR

Geothermometers are commonly used to reconstruct the diagenetic and thermal history of rocks. However, characterizing the timing, origin, and temperature of paleofluid flow remains challenging because it must be assessed indirectly through the analysis of microscopic cements that precipitate and fill intergranular spaces during fluid circulation. Here, we measure both the clumped isotope (Δ47) temperature and in situ U-Pb age of individual diagenetic calcite cements within a sedimentary section of the Paris Basin (France), whose thermal history has been previously inferred to be 70 °C) have been measured for calcite cements containing single-phase aqueous fluid inclusions, challenging the commonly accepted assertion that the absence of nucleation of a vapor phase indicates crystallization at low temperature (∼<70 °C). We suggest that the kinetics of mineralization events prevented the recording of short-lived hot fluid flows by other