Editing Tuff (section)

===Tephrochronology===
{{Main|Tephrochronology}}
[[File:Pilar Formation outcrop.jpg|thumb|Pilar Formation outcrop showing metatuff beds used for radiometric dating]]

Tuffs are deposited geologically instantaneously and often over a large region. This makes them highly useful as time-stratigraphic markers. The use of tuffs and other tephra deposits in this manner is known as tephrochronology and is particularly useful for [[Quaternary]] chronostratigraphy. Individual tuff beds can be "fingerprinted" by their chemical composition and phenocryst assemblages.<ref name="philpotts-ague-2009-74">Philpotts and Ague 2009, p. 74</ref> Absolute ages for tuff beds can be determined by [[K-Ar]], [[Argon–argon dating|Ar-Ar]], or [[carbon-14 dating]].{{sfn|Fisher|Schmincke|1984|pp=352-356}} [[Zircon]] grains found in many tuffs are highly durable and can survive even metamorphism of the host tuff to schist, allowing absolute ages to be assigned to ancient metamorphic rocks. For example, dating of zircons in a metamorphosed tuff bed in the [[Pilar Formation]] provided some of the first evidence for the [[Picuris orogeny]].<ref>{{cite journal |last1=Daniel |first1=Christopher G. |last2=Pfeifer |first2=Lily S. |last3=Jones |first3=James V III |last4=McFarlane |first4=Christopher M. |title=Detrital zircon evidence for non-Laurentian provenance, Mesoproterozoic (ca. 1490–1450 Ma) deposition and orogenesis in a reconstructed orogenic belt, northern New Mexico, USA: Defining the Picuris orogeny |journal=GSA Bulletin |date=2013 |volume=125 |issue=9–10 |pages=1423–1441 |doi=10.1130/B30804.1 |bibcode=2013GSAB..125.1423D |url=https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/125/9-10/1423/125945/Detrital-zircon-evidence-for-non-Laurentian?redirectedFrom=fulltext |access-date=17 April 2020}}</ref>