Researchers can first apply an absolute dating method to the layer.
They then use that absolute date to establish a relative age for fossils and artifacts in relation to that layer. Anything below the Taupo tephra is earlier than 232; anything above it is later.
After archaeologists have thoroughly surveyed the site they begin excavation. Then archaeologists excavate the site using trowels, shovels, and various other tools.
Layers of rock build one atop another — find a fossil or artifact in one layer, and you can reasonably assume it’s older than anything above it.
A datum is a fixed reference point, often one placed by the U. The context of the artifact is just as important as the artifact itself, so the artifacts are always carefully mapped and documented.
Archaeologists also look for features while excavating a site.
Paleontologists still commonly use biostratigraphy to date fossils, often in combination with paleomagnetism and tephrochronology.
A submethod within biostratigraphy is faunal association: Sometimes researchers can determine a rough age for a fossil based on established ages of other fauna from the same layer — especially microfauna, which evolve faster, creating shorter spans in the fossil record for each species.