In the Paisley Caves, the combination of south-facing orientation (maximizing solar warming and evaporation during the summer season), the protection from rain, and the alkaline chemistry of the sediment created conditions where desiccation of deposited biological material could occur relatively quickly and where the desiccated material could remain in a stable state for extended periods.

The alkaline chemistry of the cave sediment is particularly important for DNA preservation.

DNA degrades through several mechanisms, and one of the most important is acid hydrolysis — the chemical breakdown of the DNA backbone by acidic conditions.

In alkaline sediments, this mechanism is suppressed, allowing DNA to survive longer than it would in the acidic conditions of many forest soils or humid sediment environments.

The Great Basin’s carbonate-rich sediments are naturally alkaline, contributing to the preservation of both the DNA and the lipid molecules that the 2020 study analyzed.