相距3?20km的岭头、罾口河、俵口和空港物流中心4处埋藏牡蛎礁体的年代学研究证实,开始发育的时间不同,但同时在4.2?4.0kacal BP时结束建礁,即其灭亡与4.2ka事件在时间上重合。岭头、罾口河剖面O稳定同位素和罾口河剖面孢粉数据进一步表明,4.5?4.3ka cal BP时研究区气候出现变冷变干的趋势,4.3?4.2ka cal BP逐渐好转,推测这一气候波动变化过程可能是对4.2ka事件的响应。
英文摘要:
AMS ~(14)C dating revealed that initiation timing of the four buried oyster reefs, Lingtou, Zengkouhe, Biaokou and Airport Logistic Center, 3?20km apart from each other, was different but the reef building up at the four sites were almost simultaneously finished by accumulation of the thick muddy sediments at 4.2?4.0ka cal BP or so, which coincided with the '4.2ka event'. Furthermore, oxygen isotope study of the endogenic carbonate mud taken from the interior of the articulated oyster shells and the overlying muddy sediments in Zengkouhe and Lingtou profiles and pollen analysis from the same sampling positions were carried out. Both results indicate that the local climate condition tended to be cold and dry during the period of 4.5?4.3ka cal BP and then began to ameliorate in 4.3?4.2ka cal BP. The authors hold that this climate fluctuation was probably a response to the 4.2ka event in the study area.