Dating of speleothems in Kartchner Caverns, Arizona

Uranium-series dates on calcite travertine samples collected from Kartchner Caverns range from ~200-40 Ka. These dates span from the Illinoian glacial to the Wisconsin glacial, but the majority cluster within the wetter Sangamon interglacial. Petromorphic vein quartz (>35 Ka from alpha spectrometry and >1 Ma from ²³⁴U/²³⁸U ratios) dates from an earlier thermal episode associated with Basin and Range faulting. All that can be surmised about the …