The use of the lichen genus Rhizocarpon in lichenometric dating with special reference to Holocene glacial events

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  • Richard A. Armstrong

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Lichenometry is one of the most widely used methods of dating the surface age of substrata including rock surfaces, boulders, walls, and archaeological remains and has been particularly important in dating late Holocene glacial events. Yellow-green species of the crustose genus Rhizocarpon have been the most useful lichens in lichenometry because of their low growth rates and longevity. This review describes: (1) the biology of the genus Rhizocarpon, (2) growth rates and longevity, (3) environmental growth effects, (4) methods of estimating lichen age, (5) the methodology of lichenometry, (6) applications to dating glacial events, and (7) future research. Lichenometry depends on many assumptions, most critically that if the lag time before colonisation of a substratum is known and lichen age can be estimated, then a minimum surface age date can be obtained by measuring the size of the largest Rhizocarpon thallus. Lichen age can be estimated by calibrating thallus size against surfaces of known age (‘indirect lichenometry’), by constructing a growth rate-size curve from direct measurement of growth (‘direct lichenometry’), using radio-carbon (RC) dating, or from lichen ‘growth rings’. Future research should include a more rigorous investigation of the assumptions of lichenometry, especially whether the largest thallus present at a site is a good indicator of substratum age, and further studies on the establishment, development, growth, senescence, and mortality of Rhizocarpon lichens.


Publication date2015
Publication titleAdvances in environmental research
EditorsJustin A. Daniels
Place of PublicationHauppauge, NY (US)
PublisherNova science
Number of pages28
ISBN (Electronic)978-1-63482-380-7
ISBN (Print)978-1-63482-366-1
Original languageEnglish

Publication series

NameAdvances in environmental research


  • lichenometry, rhizocarpon geographicum, Lichen growth, growth rate-size curve, growth rings, Holocene glacial events

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