But gradual aeolian accumulation produces a sediment record that is, while not perfectly undisturbed, amenable to stratigraphic interpretation using both macroscopic observation and micromorphological analysis.

Superimposed on the primary aeolian accumulation are the secondary processes that all cave sediments experience: the periodic input of water-transported sediment during flood events associated with high lake levels; the bioturbation caused by rodents and other burrowing animals; the physical disturbance caused by the activities of human and animal occupants; and the slow chemical transformation of the sediment matrix through weathering and diagenesis.

The micromorphological analysis of the Paisley sediment was specifically designed to characterize these secondary processes and assess their effects on the integrity of the primary stratigraphic sequence.

The results of that analysis are what allow researchers to make statements about stratigraphic integrity with the confidence that the 2012 paper expressed — not a claim of perfect undisturbance, but a well-documented assessment that the primary sequence is sufficiently intact to support the chronological interpretations drawn from it.

The coprolites are preserved within this sediment matrix.

They represent discrete organic objects that were deposited at specific moments in time — when a human or non-human visitor to the cave used it as a latrine site — and that were subsequently buried by the continuing accumulation of wind-driven sediment.

Their relationship to the surrounding sediment matrix is one of the key questions that the stratigraphic and micromorphological analysis was designed to address, and the conclusion that the dated coprolites are in primary or near-primary depositional context is the foundation on which the chronological interpretation of the entire Paisley pre-Clovis case rests.

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