Two new Icelandic tephra markers: The Hekla O tephra layer, 6060 cal. yr BP, and Hekla DH tephra layer, \\~6650 cal. yr BP. Land-sea correlation of mid-Holocene tephra markers.
The Schmidt hammer as a Holocene calibrated-age dating technique: Testing the form of the R-value-age relationship and defining the predicted-age errors.