The Stratigraphy Problem in Detail

The criticism of the cave’s stratigraphic integrity — the concern that the sediment layers might not represent a reliable record of the chronological sequence of human occupation — was among the more complex challenges facing the Paisley evidence, and addressing it required the most sustained and detailed archaeological response.

Stratigraphic analysis is the foundation of archaeological dating.

The principle of superposition — the observation that in an undisturbed sediment sequence, older materials are below younger materials — allows archaeologists to establish relative chronologies from the vertical position of materials in a site.

When that principle is violated by natural or human disturbance, the relative chronology becomes unreliable, and radiocarbon dates associated with a disturbed layer may not accurately reflect the age of all the materials in that layer.