For bone, the specific material being dated is usually collagen — the protein fraction of bone that, in well-preserved specimens, retains original organic material and is relatively resistant to contamination compared to the inorganic fraction.

Collagen dating has become standard because bone apatite — the mineral fraction — is much more susceptible to exchange with environmental carbonates and produces unreliable dates.

Good collagen preservation requires that the bone be well-sealed in its depositional environment, that groundwater chemistry not have been strongly acidic (which destroys collagen), and that the physical integrity of the collagen structure be maintained over time.

The Buhl burial was in dry, windblown sediments above the water table, which is generally a favorable preservation environment for collagen.