A minimum age for canyon incision and for the extinct molossid bat, Tadarida constantinei, from Carlsbad Caverns National Park, New Mexico

Slaughter Canyon Cave (or New Cave), Carlsbad Caverns National Park, southeastern New Mexico, opens in the wall of Slaughter Canyon, 174 m above the present level of the canyon floor. It contains bone-bearing, water-laid sediments capped by a double layer of calcite. TIMS U-Th dates on the two layers are 66.0 ± 0.3 ka and 209 ±9 ka. Deposition of these two laterally-extensive calcite layers suggests wet periods in this currently-arid region during MIS 4 and 7. The date on the lower layers suggests that the elastic deposit was emplaced no later than MIS 8. This yields a maximum estimate for downcutting rate of the canyon of∼0.87 mm yr-1 during the Late Pleistocene. The clastic deposit contains bones of the molossid bat Tadarida constantinei Lawrence 1960: the date of 209 ± 9 ka is thus a minimum age for this extinct bat.