Investigation of Dating Technique
Lichenometry
Lichenometry offers a wide range of applications for the short term dating of certain rocks, up to 10,000 years. The dating method uses known lichen growth curves of different lichen species to date the object of interest. Most lichenometry experiments use the Rhizocarpon species of lichen. The most simple method of dating using lichenometry is to measure the diameter of the largest lichen of each species identified on the rock face. With a calibrated lichen growth curve of the lichen species measured, an age can be inferred.
Lichenometry has multiple geolgoic applications, in which the ages of lichen are used to date ancient floods and flood plains, seismic activities, glacial deposits, and more recently, lichenometry has been used to evaluate the speed of retreating glaciers due to climate change.
Lichens, Lichenometry and Global Warming - Richard Armstrong
This paper out of Columbia University explains some of the pros and cons of lichen dating, as well as the applications for measuring impacts of global climate change. Specifically, work has been done that highlights increased avalanche activity in Norway that has been attributed to faster and earlier spring snowmelts. Lichenometry has also highlighted glacial retreat rates, and scientists have seen that these rates have been accelerating since the 1940s. Pictured above is a lichen growth curve for the poppular lichen species Rhizocarpon.
Armstrong, R. A. (2004) Lichens, Lichenometry and Global Warming. Microbiologist, September 2004, 32-35.
A review of Lichenometric Dating and Its Applications to Archaeology - James Benedict
I found this paper interesting becasue it introduces a different type of application for lichenometry that isn't necesarilly geological. This paper talks about the use of lichenometry for archaeological purposes. This can be useful for dating rock faces of historical importance such as the Easter Island moai, ancient quarrys, or ancient civilization buildings and structures. The paper walks through multiple insances of how lichenometry has been used to date features similar to those mentioned previously.
Benedict, J. (2009). A Review of Lichenometric Dating and Its Applications to Archaeology. American Antiquity, 74(1)