渤海湾北岸海相贝壳AMS 14C测年与“驻留时间”

AMS;C ages of marine shells and the residence time effect on the north coastal of Bohai Bay

以渤海湾地区曹妃甸沿海全新统埋藏贝壳为研究对象,对比同一层位中不同形态贝壳的AMS;C年龄,总结贝壳形态-年龄差异及所指示的"驻留时间"。测年结果显示,在研究区同一地层中,用于测年的腹足类-单瓣壳-贝屑3种形态贝壳的年龄通常具有依次变小的特征,以校正年龄中值计算,年龄差值总体介于52~466 yr。以2倍标准偏差的校正年龄对比,不同形态贝壳的年龄部分接近。这一结果明显不同于渤海湾西岸贝壳堤中同一单层同种贝壳的闭合壳-单瓣壳-贝壳碎片的年龄逐渐变老的次序。这种贝壳形态—年龄序列的差别系沉积环境不同,搬运营力及距离差异性导致。

In order to summarize the differences in shell form-age and the indicated "residence time", the marine shells buried in the Holocene on the coastal of Caofeidian, north of Bohai Bay were taken and AMS;C ages of different shell forms in the same horizon layer were compared. The dating results showed that the ages of the three shell forms, gastropods, disarticulated valve and shell hash, which were used for dating, usually decreased in turn. the age difference was generally between 52 and 466 yr based on the corrected median age. The age of different shell forms was close to each other by using 2 times standard deviation. This result is obviously different from the sequence of the gradual aging of the including articulated shell-disarticulated valve-shell hash of the same species in the shelly layers on the west coast of Bohai Bay. The difference of the shell morpho-age sequence is caused by the difference of sediment environment, transport capacity and distance.