摘要
文章基于山东半岛岩溶洞穴(上小峰洞)一根长约41 cm的石笋SD1的铀系测年和稳定同位素组成分析,获得138. 0~125. 8 ka B. P.平均分辨率为30年的石笋δ18O 和δ13C时间序列,并据此讨论了倒数第二次冰消期区域气候和环境变化的特征及与全球变化的联系.在倒数第二次冰消期,上小峰洞石笋( SD1)δ18O的变化与中国南方石笋δ18O的变化具有类似的阶段变化特征,进一步确认了冰消期北大西洋气候对亚洲季风的重要影响.通过对山东石笋高分辨δ18O记录进行时间序列分析,发现该记录存在显著的约60年、 75年和1620年周期,表明太阳活动和北大西洋涛动与该地区气候变化有紧密的联系.同时,通过对比东亚季风区高分辨率石笋记录,认为在倒数第二次冰消期为"两步冰消"的变化特征.除此之外,上小峰洞石笋碳酸盐δ18O冰期和间冰期平均值的差异仅为0. 7‰,远小于内陆洞穴石笋碳酸盐δ18O冰期和间冰期平均值的差异(羊口洞约为1. 4‰,董哥洞约为2. 2‰,三宝洞约为2. 4‰).这一显著差异可能主要源于海岸线迁移造成的海陆格局的变化对区域季风降水及降水氧同位素组成的重要影响;并且冰期-间冰期海平面变化对近海环境记录、大陆架下垫面、海洋沉积物气候指标等都可能产生影响.
We present the sequences of δ18O and δ13C from 125.8 ka B. P. to 138.0 ka B. P. by a length of 41 cm speleothem sample with an average resolution of 30 years based on the 230 Th dating and stable isotope composition analysis of stalagmite (SD1) from Shangxiaofeng Cave (36°21'N, 118°01'E;560 m a.s.l.) in Shandong Peninsula, and discussed the characteristics of regional climate and environmental changes as well as their linkage with global change during penultimate deglaciation. In total, 18 subsamples were dated by 230 Th dating method and 408 powdered subsamples were drilled by using a handheld carbide dental drill at intervals of 1 mm along the central growth axes of this stalagmite for stable isotope analysis. The change pattern of speleothem δ18O between Shangxiaofeng Cave (SD1) and those of Southern China has similarities during penultimate deglaciation, this further confirms that the important influence of the North Atlantic climate on the Asian monsoon during the deglaciation. The multi-taper spectral analysis reveals that δ18O in Shandong region displays significant ca. 60, 75 and 1620 years quasi-cycles over SD1 records, implying solar activity and the North Atlantic Oscillation (NAO) closely link with the climate change in our study site. Meanwhile, there is a "two-step" deglaciation process during penultimate deglacial. Additionally, the δ18O magnitude of the glacial-interglacial change (ca. 0.7 ‰) is significantly smaller compared to the δ18O records from inland and relatively high elevation caves (Yangkou, Dongge and Sanbao caves)(1.4 ‰, 2.2 ‰ and 2.4 ‰). This significant difference likely result from changes in sea-land configuration shape the monsoon precipitation and its isotope composition during the penultimate deglacial. The sea level changes during the glacial-interglacial transition period may also have an impact on offshore environmental records, continental shelf underlying surfaces, and marine sediment climate proxies.
作者
薛刚
蔡演军
马乐
成星
李东
卫莹莹
Xue Gang;Cai Yanjun;Ma Le;Cheng Xing;Li Dong;Wei Yingying(State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Science, Xi'an 710061, Shaanxi;University of Chinese Academy of Sciences, Beijing 100049;CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, Shaanxi;Open Studio for OCCEC, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, Shandong;Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710054, Shaanxi)
出处
《第四纪研究》
CAS
CSCD
北大核心
2019年第4期812-824,共13页
Quaternary Sciences
基金
国家重点基础研究发展计划项目(批准号:2017YFA0603401)资助.
关键词
石笋
氧同位素
倒二冰消期
弱季风期
海岸线移动
stalagmite
oxygen isotope
penultimate deglaciation
weak monsoon interval
coastline shift
