The Cretaceous-Tertiary boundary is characterized by mass extinctions triggered by a large body impact into predominantly limestone-, dolomite-, and anhydrite-bearing sediments of the Yucatan peninsula, Mexico. Decomposition of these volatile-rich minerals and associated deterioration of the atmosphere and hydrosphere rank among the most prominent kill mechanisms during this global catastrophe. As a consequence, we conducted optical and scanning electron microscopy and X-ray diffraction studies of anhydrite (CaSO₄) that was experimentally shock-loaded to pressures from 4 to 64 GPa to determine the shock damage and potential loss of volatiles as a function of shock stress. We did not find...