摘要
地处典型东亚季风区的神农架大九湖盆地有华中地区面积最大、海拔最高的亚高山泥炭沼泽湿地。对盆地中心部位钻孔DJH-2中821～430cm泥炭沉积进行花粉浓缩物AMSC测年,经校正发现其沉积时段为59.8～26.1kaB.P,与MIS 3阶段相对应。研究显示,在MIS 3阶段研究区气候环境适宜植被的生长和有机质的保存,基于α-纤维素δ^(13)C重建的大气湿度显示平均为72%的湿度值总体略高于全新世晚期,且MIS 3早期(60～49kaB.P.)和晚期(38.5～26.1 kaB.P.)较高,大气湿度平均为75%和72%,中期(49.0～38.5kaB.P.)略低,平均69%,温度则由早期到晚期呈现逐渐降低趋势。高分辨率的泥炭记录显示千年尺度的气候变化呈现5个波动旋回,期间出现的4次冷干事件与H冷事件一一对应,并且存在多次暖(温)湿事件对应于D-O暖事件。此段沼泽沉积是大九湖对这一时期东亚夏季风强度明显增强的直接响应,与全球众多记录对比揭示出MIS 3阶段神农架泥炭记录在岁差尺度东亚夏季风环流强度主要受太阳辐射控制,其功率谱分析显示存在的多个显著周期为千年尺度上东亚夏季风强度主要受太阳输出量控制的观点提供了有力支持。
The Dajiuhn Basin （ 31 °27＇ ～ 31 °32＇N, 109 °57＇ ～ 110°02 ＇E） is located at Shennongjia, which is a typical East Asian Monsoon region,and preserves a largest and highest sub-alpine peat wetlands of Central China. A long core （DJH-2） with ca. 45m was obtained in the central of the basin（31°29＇N, 109°59＇E） , which was sampled at 1 cm intervals. TOC and ct-cellulose δ13C were measured for all samples, and plant residues were identified for the selected samples in peat layers. AMS14C dating by pollen concentration showed that the peat layer with black and brown color obtained between 821 ～ 430cm on the top of DJH-2 core covers 59.8 -26.1 kaB. P., that corresponds with MIS 3 stage period. The history of significant enhancement of the East Asian summer monsoon during MIS 3 was directly recorded. Results showed the vegetation was suitable for growth and organic matter was well preserved during MIS 3 at Shennongjia Basin. The atmospheric relative humidity during MIS 3 was reconstructed based on c^-cellulose $13C ,and its average value was 72% which was higher than that in the Late Holoeene. In the early （60.0 ～ 49.0kaB. P. ） , mid （49.0～ 38.5kaB. P. ） and late （38.5 ～ 26. lkaB. P. ） period of MIS 3, they were 75%,69% and 72% respectively. The atmospheric relative humidity during the early MIS 3 was higher than the value in late and mid period,it is consistent with temperature decreasing trend from early to late in MIS 3. Five wave cycles of millennial-scale climate change was recorded. The four cold and dry events were consistent with Heinrich events and the warm events was corresponding with D-O warm events. Compared with others records on the world, this paper reveals that the variation of East Asia summer monsoon circulation intensity mainly controlled by solar radiation in the millennial-scale, and power spectral analysis on peat records of the Dajiuhu Basin shows a number of significant cycles which provide a strong support point of view for that East Asian summ
出处
《第四纪研究》
CAS
CSCD
北大核心
2013年第1期155-166,共12页
Quaternary Sciences
基金
福建省公益类科研院所专项基金项目(批准号:2011R1037-7)
福建省自然科学基金项目(批准号:2011J05107)
福建师范大学青年骨干教师资助基金项目(批准号:FJSDKY2012009)
国家自然科学基金项目(批准号:40972112和40671193)共同资助
