Shells were aged by the Sclerochronology Laboratory at the Pacific Biological Station using the dendrochronological technique of cross-dating
. The year of death of the dead shells was determined by using the novel technique of overlapping the synchronous growth patterns of the live and dead shells.
and quality control of tree-ring measurement were performed using the program COFECHA (Holmes, 1983).
Douglass called it cross-dating
. He matched patterns of tree rings, like the flagstaff Signature, from trees that have overlapping lifespans.
is a method of pattern matching a tree's growth signals of unknown age (floating chronology) to that of a known pattern that is locked in time (master chronology).
Rinntech, Heidelberg, Germany), and cross-dating
quality was checked using COFECHA (Holmes, 1983).
The quality of their cross-dating
was checked by the program COFECHA  according to the mean correlation of each series with all other series per sample set.
We developed two floating sequences of cross-dated tree rings with no cross-dating
between these two sequences suggesting the possibility of two different stands with different absolute ages.
Living white spruce trees near the glacier's terminus in the Slims valley are less than about 290 years old (Allen, 1982) and thus of limited value for cross-dating
. Consequently, we dated the Kaskawulsh Glacier samples using a millennium-length white spruce ring-width chronology developed from trees that grew at the Landslide site near the southwest end of Kluane Lake (Fig.
Although the trenches were stratigraphically discontinuous and thus require cross-dating
, they provide new data on Khabur-region chronology and complement the sequence from Leilan.
If two or more independent methods yield the same answer within the quoted standard deviations, it is hard to argue that the result is not correct, so the most secure numerical dating results come from cross-dating
the same site, which in Australia usually means the radiocarbon and luminescence methods.
Within a 19 X 32 km area, local fire chronologies were established at 203 points by cross-dating
fire scars on 1133 wood samples, the earliest dating back to the 1100s.
Years were assigned to annual rings using the skeleton plot and cross-dating
method (Stokes and Smiley, 1968; Fritts, 1976).