The sedimentation or annual varve thickness is relatively uniform, typically 1.2 mm per yr for present conditions in Lake Suigetsu which is located near the coast of the Sea of Japan.
Recently scientists took a 75-m long continuous core from the center of the lake for close analysis including AMS 14C measurements on more than 250 terrestrial macrofossil samples of the annual laminated sediments.
The 29,100 yr Lake Suigetsu chronology then covers the absolute age range from 8830 to 37,930 cal BP. Matching of the 29,100-yr long floating varve chronology from Lake Suigetsu to the absolute chronology.
To allow detailed observation of the sediments, the well-cleaned surfaces of sediments were scanned with a digital camera.
By means of computer image analysis of digital pictures, we found that the much less distinct varves observed in some intervals during the deglaciation and Glacial could be determined only with a relatively large error.
The age below 30.45 m depth is obtained by assuming a constant sedimentation in the Glacial (0.62 mm yr-1).
In order to reconstruct the calendar time scale, we compared the Lake Suigetsu chronology with calibration curves obtained from recently revised absolute German oak and the floating German pine calibration curves (2).