Key to the wiggle-match dating method is radiocarbon dating samples through a known sequence. In our case, the known sequence is the structure of the trees which were used in construction of our crannogs. The rings within the trees represent, of course, single-years. So we sample rings through this sequence using microscopes and scalpels to cut out groups of rings as the individual samples. These samples will then be radiocarbon dated, but importantly we’ll know precisely where in the sequence they should fall (this group of rings comes after that group but before that other group…). This makes counting and cutting out the rings very important. We want to be absolutely sure to precisely sample the right rings.

Counting and Cutting Rings

Oak timber under the microscope.

The first wiggle-match we will analyse comes from Milton Morenish crannog. The dendrochronological assessment identified a group of three trees all felled in the same late winter/early spring, and the longest lived among these trees was 65 years old. We have now cut out the rings in sequential blocks and are beginning standard pre-treatment methods prior to measuring the sample in the AMS. The pre-treatment process will be covered in our next post, so be sure to check back soon!