阿勒罗德至新仙女木早期气候转型特征  

THE CHARACTERISTICS OF CLIMATIC TRANSITION FROM ALLERΦD TO EARLY YOUNGER DRYAS

作　　者：邱庆伦[1] 汪永进[1] 

机构地区：[1]南京师范大学地理科学学院,南京210097

出　　处：《海洋地质与第四纪地质》2007年第2期107-112,共6页Marine Geology & Quaternary Geology

基　　金：国家杰出青年科学基金项目(40225007)

摘　　要：湖北神农架青天洞QT17石笋的3个U-Th年龄和持续1440a的纹层计数序列提供了13.5～12.1kaBP期间平均4a分辨率的δ18O东亚季风强度记录。该记录与Cariaco盆地纹泥灰度记录显示阿勒罗德至新仙女木早期气候呈现低幅振荡特征,而格棱兰GISP2和GRIP冰心温度记录在同时段则呈现大幅高频振荡。4个记录的气候转型时间在测年误差范围内基本一致,一定程度上说明北半球高低纬千年尺度气候事件同步变化。然而,该期间东亚季风气候转型持续时间近550a(纹层计数年),而大西洋气候记录仅有230～400a,可能由于季风气候降水同位素部分受来自海洋水源同位素的影响。Three U-Th dates, 336 pairs of δ^18 O data and 1440 laminar-thicknesses have been measured for QT17 stalagmite from Qingtian Cave in Shennongjia area, Hubei Province. An averaged 4-year-resolution absolute-dated oxygen isotope record from Qingtian Cave represents East Asian monsoon history during the period from 13.5 to 12.1 kaBP. This record bears a high similarity to a grey level record of varved sediments from Cariaco basin in terms of their fluctuation and amplitude at the transition during the period from Allerod to early Younger Dryas. On the contrary, both new Greenland ice cores （ GISP2 and GRIP） δ^18 O records show large amplitude during that period. Within the dating error, the four records are ap proximately synchronous at millennical time scale, which supports the coupled link between northern high and low latitudes in climate systems. Despite of the four records in phase, these records display different durations for this transition. We can see from the records in Atlantic climate region （including the two Greenland ice cores）and Caricao basin that the transition lasts 230-400 years only. From the annual layer counting result, our monsoon record shows much longer duration, about 550 years. We interpret the long duration as a mixed isotope effect of the monsoon precipitation and its sourced sea water.

关 键 词：石笋 YD事件 气候转型 青天洞 

分 类 号：P532[天文地球—古生物学与地层学]