The thermoluminescence (TL) properties of shocked Coconino sandstone and Kaibab dolomite from Meteor Crater, Arizona, have been studied. Equivalent dose (ED), a measure of stored TL, decreases with increasing shock (decreasing TL sensitivity) but becomes shock independent at high shock grades. The minimum shock grade at which ED becomes shock independent, the shock threshold for resetting preimpact TL to a negligible level, falls within petrographic shock class 2 as defined by Kieffer and corresponds to an equilibrated state at about 10 GPa and 700 ¿C. Shocked Coconino fragments suitable for evaluation of the formation age of the crater using TL are those shocked in excess of the resetting threshold. The average postimpact temperature of the crater floor, about 190 ¿C based on the TL of samples heated during burial, is consistent with impact energy estimates for the crater.