A study of determining the tree-ring age with a precision of one year by 14C wiggle matching

本研究旨在探讨利用AMS对考古遗址或地质沉积物中出土的木材年轮进行14 C测年，并应用14 C摆动匹配法确定其年轮年龄的可能性。我们首先测量了日本鹿儿岛屋久岛和奈良室路寺的日本雪松年轮的~（14）C年龄。的样品树dendrochronologically提前。61年轮（AD 1617 -1739）从室路树，173（AD 1413 -1615）和78环（AD 881 -1072）从屋久岛树的14 C测年和他们的年龄值进行了比较，从国际公认的IntCa 104 14 C年龄校准数据的14 C值。14 C年龄在测量误差范围内相互一致，但日本树木的14 C年龄有比IntCa 104数据更老的趋势。其次，室路树的55个年轮（AD 1631 -1739）和屋久岛树的142个年轮（AD 1413 -1554）与IntCa 104数据进行了摆动匹配。匹配产生了一个完美的巧合，14 C确定的年龄与树木的树木日期为+/-2年的不确定性（95%的置信度）的室路树。对于Yaku岛树，14 C确定的年龄是由4年以上的树树，一个+/-2年的不确定性。这表明，如果对一棵树的年轮进行大量的测定，那么用摆动匹配法可以估算出一棵树的年龄，其精度可达一年左右。我们还尝试用摆动匹配法测定了考古和地质木材样品的最外年轮。由此可以得出结论，这种方法的精度远远高于仅对树木年轮最外层进行~（14）C测年的常规方法。

This research aims to investigate the possibility of determining the age of annual ring for a wood sample excavated from archeological sites or geological sediments with a precision of one year, by 14C dating of their annual rings with AMS and applying 14C wiggle-matching. We first measured 14C ages of individual annual rings as many as possible that were separated from Japanese cedar trees grown in Yaku Island, Kagoshima, and at Muroji temple, Nara, Japan. The sample trees were dated dendrochronologically in advance.61 annual rings (AD1617-1739) from the Muroji tree, 173 (AD1413-1615) and 78 rings (AD881-1072) from the Yaku-Island tree were 14C dated and their age values are compared with respective 14C values from the internationally accepted IntCa104 14C-age calibration data. The 14C ages were consistent with one another within measurement errors, but a tendency that 14C ages of Japanese trees were older than IntCa104 data for respective annual rings.Next, 55 annual rings (AD1631-1739) from the Muroji tree and 142 rings (AD1413-1554) from the Yaku-Island tree were wiggle-matched to the IntCa104 data. The matching yielded a perfect coincidence of 14C-determined age to dendro-dated one with +/-2 year uncertainty (95% confidence) for the Muroji tree. For the Yaku-island tree, 14C-determined age was older by 4 years than the dendro-dated one with +/-2 year uncertainty. It is clearly suggested that age estimation of a tree is possible with a precision of about one year by wiggle matching if a larger number of annual rings will be dated for the sample tree.We also tried to date the outermost ring of archeological and geological wood samples by wiggle matching, and could conclude that a far better accuracy is obtained by this method than by the ordinary method of 14C dating of only the outermost annual ring of the woods.