作　　者： ; ; ; ; ; ;

机构地区： 中国科学院广州地球化学研究所

出　　处： 《第四纪研究》 2007年第4期492-498,共7页

摘　　要： 运用AMS-14C定年技术,研究了被埋藏水松古木的发育和死亡时间以及土壤剖面中总有机碳的14C表观年龄和细根的14C年龄。结果表明:该地区的水松古木开始发育和死亡的时间大致为4～3kaB·P.。根据土壤有机碳14C的表观年龄,该土壤剖面的14C年代地层可以分为3层,分别为:1)表层,2634±32～3305±29aB·P.;2)腐殖层,3305±29～3813±31aB·P.;3)基底,3813±31～4544±33aB·P.。基底、腐殖土层和表层的沉积速率分别为0·55mm/a,4·33mm/a和0·26mm/a。细根的14C年龄变化范围为2290±29～3542±28aB·P.,较同层位的土壤有机碳的年龄年轻。腐殖层土壤中有机碳含量高达33%～46%,大多数有机碳仍处于未分解状态。该地区自4～3kaB·P.以来,环境演化可能经历了由陆到沼泽再到被水淹没最后又变成陆地的过程,植被从以水松为优势种的森林群落演化成当前以常绿阔叶林为主的森林生态群落,气候和海平面变化、地质构造运动和人类活动是这种环境演化的主要驱动因子。 The ＂underground forest ecosystem＂ in Sihui, Guangdong Province with a developmental process preserved offers an opportunity to better understand the environment evolution history of the Zhujiang River Delta, which was previously obscured due to the lack of chronological research of the buried ancient timbers. Accelerator mass spectrometry （AMS）-^14C dating has been carried out on two buried ancient timbers for the reconstruction of the environmental evolution during the related time. The ＂underground forest ecosystem＂ was dominated by Glyptostrobus pensilis although the area is occupied by evergreen broadleaf forests today. ^14C ages of the bark and core of the ancient Glyptostrobus pensilis-1 were 3893 ± 27aB. P. and 3232 ± 27aB. P., implying that the tree had lived for about 600 years, while the those of Glyptostrobus pensilis-2 are 3661 ± 25aB. P. and 3406 ± 23aB. P. ,,indicating that it had lived for about 260 years. The trees were most likely to be cut by early residents, who might have taken the trunk away and left the less useful parts such as branches and leaves in the position forming the humus layer. The soil profile is. about 3 meters high. The stratum can be divided into three different layers： the top layer of 40cm, the humus layer of 220cm, and the floor layer of 40cm. The measured ^14C ages based on soil organic carbon of each layer are 2634 ± 32 ～ 3305 ± 29aB. P., 3305 ± 29 ～ 3813 ± 31aB. P., and 3813 ± 31 ～ 4544 ± 33aB. P., respectively. It＇s obvious that the ＂underground forest ecosystem＂ began to develop at about 4kaB. P. and ended at about 3kaB. P. The ^14C ages of fine roots which ranged from 2290 ± 29aB. P. to 3542 ± 28aB. P. were obviously younger than those of soil organic carbon （ SOC ） at the same sampling layer, indicating an earlier formation of SOC surrounding the roots. High contents of SOC ranging between 33% and 46% were another character in the soil profile implying that most SOC still remains undeeomposed. The research region mi

关 键 词： 四会 地下森林 细根 古木 地层年代

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