Lichenometric constraints on the age of the Huashan Grottoes, East China

Lichenometry is a method of dating that has been widely used in glaciated areas for determining the minimum age of exposure of a geomorphic landform during the late Holocene. This paper presents a regional calibration data set of lichen thallus sizes versus rock surface ages for the Huashan area, East China, based on measurements of yellow-green Rhizocarpon lichens on the known-age substrates at eight sites. An empirical relationship between thallus sizes and rock surface ages was established using both the traditional regression and the Bayesian approaches. Using the Bayesian calibration, the minimum age of the Huashan Grottoes was dated from 450 ± 60 to 330 ± 60 years ago, corresponding to the late Ming Dynasty (AD 1477-1632). These dates are generally consistent with those predicted from the regression-based linear growth curve. Our results suggest that applications of this technique can be safely extended to the non-glaciated areas.