lichenometry

lichen +‎ -metry.

lichenometry (uncountable)

1. (archaeology, paleontology, geomorphology) A geomorphic method of geochronologic dating that uses lichen growth to determine the age of exposed rock.

   In lichenometry, a lichen is presumed to grow radially at a specific, constant rate: this rate is used to estimate the age of the largest lichen on a rock surface, and thus the length of time the rock has been exposed.

   • 2004, Jean M. Grove, Little Ice Ages: Ancient and Modern, Volume 1, 2nd edition, Taylor & Francis (Routledge), page 7:

     The sophistication of approach to lichenometry has increased markedly in the last decade or two.

   • 2011, Jason P. Briner, “Dating Glacial Landforms”, in Vijay P. Singh, Pratap Singh, Umesh K. Haritashya, editors, Encyclopedia of Snow, Ice and Glaciers, Springer, page 177:

     Lichenometry is a surface-exposure dating method that uses lichen-growth rates to infer the age of young ([a] few thousand years old or younger) glacial landforms, typically bouldery deposits such as moraines. […] Several approaches have been employed to measure lichens, and a distinct advantage of lichenometry over other techniques is its simplicity (Bradwell, 2009).

   • 2012, Matti Saarnisto, “I.4: Time-scales and dating”, in B. Huntley, T. Webb III, editors, Handbook of vegetation science, Volume 7: Vegetation history, Kluwer Academic, page 102:

     Lichenometry is a dating method which is based upon the direct relationship between lichen diameter and age.

• lichenometric