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| 广东四会古森林地下生态系统14 C地层年代学研究* | |
| 引用本文： | 丁平,沈承德,易维熙,刘克新,丁杏芳,付东坡.广东四会古森林地下生态系统14 C地层年代学研究*[J].第四纪研究,2007,27(4):492-498. |
| 作者姓名： | 丁平 沈承德 易维熙 刘克新 丁杏芳 付东坡 |
| 作者单位： | 1. 中国科学院广州地球化学研究所,广州,510640;中国科学院研究生院,北京,100049 2. 中国科学院广州地球化学研究所,广州,510640 3. 北京大学重粒子物理重点实验室,北京,100871 |
| 基金项目： | 国家自然科学基金 , 国家重点基础研究发展计划(973计划) , 中国科学院知识创新工程项目 |
| 摘 要： | 运用AMS-14 C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14 C表观年龄和细根的14 C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14 C的表观年龄,该土壤剖面的14 C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14 C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。 |
| 关 键 词： | 四会 地下森林 细根 古木 14 C地层年代 |
| 文章编号： | 1001-7410（2007）04-492-07 |
| 收稿时间： | 2007-01-31 |
| 修稿时间： | 2007-01-312007-04-22 |
14 C CHRONOLOGICAL RESEARCH OF ANCIENT FOREST COSYSTEM IN SIHUI, GUANGDONG PROVINCE |
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| Ding Ping,Shen Chengde,Yi Weixi,Liu Kexin,Ding Xingfang,Fu Dongpo.14 C CHRONOLOGICAL RESEARCH OF ANCIENT FOREST COSYSTEM IN SIHUI, GUANGDONG PROVINCE[J].Quaternary Sciences,2007,27(4):492-498. | |
| Authors: | Ding Ping Shen Chengde Yi Weixi Liu Kexin Ding Xingfang Fu Dongpo |
| Institution: | Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou510640|Graduate University of Chinese Academy of Sciences, Beijing100049|Key Laboratory of Heavy Ion Physics, Peking University, Beijing100871 |
| Abstract: | 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)-14 C 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. 14 C 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 14 C 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. Its obvious that the "underground forest ecosystem" began to develop at about 4kaB.P. and ended at about 3kaB.P. The 14 C 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 undecomposed. The research region might have experienced great environmental change during 4~3kaB.P. The land was bare before 4kaB.P. but changed into swamp at about 4kaB.P. when the "underground forest ecosystem" began to develop and the humus layer was accumulated. After about 1000 years the area was submerged along with the sea level reaching its maximum height during which the "underground forest ecosystem" was buried and airproofed. |
| Keywords: | Sihui underground forest fine root ^14C stratum chronology ancient timber |
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