Cosmogenic dating archaeology

17-Nov-2017 01:33

Novel applications of multiple nuclides with different half-lives are also being developed for determining ages of timing and amounts of soil erosion in the past, with potential applications to archaeological settings (see below).

Ar/Ar dating is limited to K-rich minerals, such as sanidine, from volcanic ashes and is primarily used to bracket the timing of site occupation.

Two chert artifacts from the region near Luxor, Egypt have yielded concentrations of cosmogenic (super 10) Be that allow calculation of nominal exposure ages of 326,000 and 304,000 years.

Both artifacts are flakes that were collected atop limestone benches of the Eocene Thebes Formation which form cliffs along the west side of the Nile.

TCN analysis is still overall in a developmental phase, although it is reasonable to state that its application is becoming more routine.

The assumptions and necessary ‘pre-requisites’ for the technique are probably less likely to be routinely well understood by archaeologists.

Tools associated with these artifacts can be attributed to the Late Acheulean or early Middle Paleolithic (the transition has been suggested to have been on the order of 250,000-300,000 years ago).

TCNs accumulate at the Earth’s surface and so provide a chronology of exposure (Siame 2008).

TCNs can also be used to determine rates of erosion, and multiple nuclides with different half-lives can be used to date the deep burial of materials (e.g., in caves where the materials are cut off from cosmic radiation).

At this stage, the work is laborious, expensive and developmental, but virtually all analytical geochronological techniques are thus as they are developed but ultimately become more affordable as they become more routine.

It is worth recalling here that the application of all geochronological techniques is never fully routine, though some are more widely understood than others and their assumptions (and the associated potential pitfalls) are part of the ‘working toolkit’ of many archaeologists.

Surface exposure dating is widely used to provide ages of deglaciation for Scotland (e.g.