Tephrochronology is the study and dating of volcanic ash layers (tephra) to create a chronological framework for geological and archaeological events. This method is significant in stratigraphy and archaeology for correlating and dating deposits across wide geographic areas.
Source Lowe, D. J. (2011). “Tephrochronology and Its Application: A Review.” Quaternary Geochronology, 6(2), 107-153.