Deposits of the El Cajete pumice at the Las Conchas mine in the Jemez Mountains, part of the youngest sequence of volcanic activity in the Valles caldera. These deposits have an estimated age of 50-60,000 years based on dating by thermoluminescence, electron spin resonance, and radiocarbon methods. The pumice deposits are over 20 m thick at this site 1.5 km from the vent, and reach a maximum thickness of at least 2.2 m at the Los Alamos National Laboratory, 28 km to the east. The black holes at the top of the ladder are sub-horizontal casts of trees that were sheared off by a volcanic blast, and are contained within surge beds. These deposits have been studied to help understand volcanic hazards in the Los Alamos area and to constrain the age of the pumice beds, which constitute a key stratigraphic marker in the region.

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