Constraining the age of rock art by dating a rockfall event using sediment and rock-surface luminescence dating techniques

Age of a prehistoric “Rodedian” cult site constrained by sediment and rock surface luminescence dating techniques

“…Habermann et al (2000), Polikreti et al (2002), Liritzis et al (2010) and Sohbati et al (2011Sohbati et al ( , 2012a have all measured luminescence signal with depth into rock surfaces that were exposed to light immediately before measurement. However, by measuring such luminescence profiles into a buried rock surface, one can determine the degree to which the surface had been bleached prior to burial (Sohbati et al, 2011(Sohbati et al, , 2012aChapot et al, 2012) and even estimate, by using an appropriate calibration, how long the surface had been exposed before burial (Sohbati et al, 2012a;Freiesleben et al, 2015).…”

Age of Barrier Canyon-style rock art constrained by cross-cutting relations and luminescence dating techniques

“…Serendipitously, a third, independent age determination for the rockfall event comes from a leaf trapped between the talus boulder and underlying sediment, dated by AMS radiocarbon methods to ∼900 y old, again within error of both OSL results. These three convergent dates provide a very solid minimum age constraint of A.D. 1100, the height of the Fremont culture, ruling out the post-Fremont hypothesis at this site (15) (Fig. 2B).…”

“…Thus, the bleached grains in the depth profile had been shielded, dosed, and reaccumulated a small luminescence signal. Indeed, it is that small reaccumulated signal that we measured in the outermost grains for one of the dates on the rockfall (15). Once recent dosing is accounted for, the profile analysis provides an exposure duration estimate of ∼700 y for the fallen block (Fig.…”

“…The optically stimulated luminescence (OSL) signals from mineral grains make it possible to date the deposition of most sediment that is exposed to a few seconds of full sunlight before burial, and its use in the earth and cultural sciences has greatly increased (10,11). Among the latest applications of OSL are techniques dating the outer surfaces of rock clasts that have become shielded from light, including those with archaeological context (12)(13)(14)(15). Recent work has furthermore used the "bleaching" profile of decreasing luminescence signal toward the surface of rock to estimate exposure time to sunlight (16,17).…”

Luminescence, Rock Surfaces

“…This study was the first to report credible exposure ages obtained using OSL surface exposure dating. In a related study, Chapot et al (2012) derived a burial age for the same sample by dating the outer 1-mm surface of the buried boulder. This age was supported by the OSL age of single grains of sediment buried under the boulder and by the 14 C age of a leaf buried between the boulder and the underlying sediment.…”