In archaeology , palaeontology , and geomorphology , lichenometry is a geomorphic method of geochronologic dating that uses lichen growth to determine the age of exposed rock , based on a presumed specific rate of increase in radial size over time. The measured growth rates of R. Lichenometry can provide dates for glacial deposits in tundra environments, lake level changes, glacial moraines , trim lines , palaeofloods,  rockfalls, seismic events associated with the rockfalls,  talus scree stabilization and former extent of permafrost or very persistent snow cover. Among the potential problems of the technique are the difficulty of correctly identifying the species, delay between exposure and colonization, varying growth rates from region to region as well as the fact that growth rates are not always constant over time, dependence of the rate of growth upon substrate texture and composition, climate, and determining which lichen is the largest. Several methods exist for dating surfaces with help of lichenometry; the most simple relies on a single largest lichen while other methods use more.
The biology behind lichenometric dating curves | SpringerLink
All publications more feeds DOI: BibTeX file. The hitherto existing growth curves for Rhizocarpon lichens for Polish mountains were prepared in a traditional way for given climatic zones. Each altitude interval determined by vegetation-climatic zones has got a specific lichen factor.
Marginal oscillations of its outlet-glaciers and general description of its morphology. Furthermore, indian women for dating gravestones are small and do not compare well in size to the geomorphic features being dated. Thirteen studies have now reported directly measured growth rates of lichens in the Rhizocarpon subgenus. No conclusions were drawn in these studies regarding the growth history of the plants. When the role of thallus size on growth rate over the ca.
Lichenometry is used to date late-Holocene terminal moraines that record glacier fluctuations. Traditionally, it relies upon dating curves that relate diameters of the largest lichens in a population to surface ages. Although widely used, the technique remains controversial, in part because lichen biology is poorly understood. We use size-frequency distributions of lichens growing on well-dated surfaces to fit demographic models for Rhizocarpon geographicum and Pseudophebe pubescens, two species commonly used for lichenometry.