摘要
通过对董哥洞石笋进行高精度的TIMS-U系测年和C、O同位素分析,建立了贵州省荔波地区15470a以来高分辨率的古气候变化时间序列。研究结果表明,荔波地区15470a以来石笋记录的冷暖事件所反映出的古季风变化,大致可分为4个气候变化阶段:(1)15470～11350a期间的晚更新世晚期——Heinrich(H1)事件和新仙女木(YD)事件期间,反映本阶段东亚冬季风强盛,气温降低,有效大气降水相对减少,表现为干旱寒冷的气候环境;(2)11350～9190a期间的早全新世——干热期,反映东亚夏季风相对增强,气温升高,有效降水相对较少,表现为干热的气候环境;(3)9190～3320a期间的中全新世——稳定的气候适宜期,反映东亚夏季风相对强盛,气温升高,有效降水相对较大,表现为温暖湿润的气候环境;(4)3320～130a期间的晚全新世降温期,反映本阶段东亚夏季风明显减弱,东亚冬季风相对增强,有效降水相对增大,而气候变化的波动频率却在增加,越至现代冷温变化时间渐趋缩短。石笋的C、O同位素记录所揭示的末次冰期最后的2次冷事件,其冷谷年龄分别为:(15440±130)a(H1事件)和(11910±70)a(YD事件),同时,还确定了终止点Ⅰ的界线年龄为(11350±70)a,并证实了末次冰期在中国南方东亚季风气候区也存在有与北大西洋H1事件和YD事件相对应的冷事件。荔波地区的古季?
The time sequence of high resolution paleoclimatic change since 1 5470a i s reconstructed by the dating ages of the high precision TIMS-U ser ies and the analysis of the carbon and oxygen isotopes from a stalagmite of Dong ge Cave in the area of Libo,Guizh ou Province.The results show that th e recor ds of the warm and cold events from the stalagmite since 15470a in t he are a of Libo reflected the paleoclimatic change which can be divided in to four sta ges:(1)the late stage of the late Pleistocen e Epoch,Heinrich event H1and Younger Drays event during15470a to 11350a indicated that the East Asi an winter monsoon was strong,the air temperature was low,the available rainfal l relatively reduced in summer season and represented the dry and cold climate e nvironment in this stage;(2)the early Holocene Epoch,the dry and hot stage from 11350a to 9190a reflec ted that the East Asian summer monsoon was strong,the air te mperature was high,the available ra infall relatively reduc ed in summer season and represented the dry and hot climate environment in this stage;(3)the middle Holocene Epoch,Climate optimum time from 9190a to 3320a refl ected that the East Asian summer monsoon was relatively strong,t he air temperature was high,the available rainfall relatively increased in su m mer season and presented the warm an d humid climate environment in this stage; (4)the late Holocene Epoch,falling tem perature time from 3320a to 13 0a shown that the East Asian summer mon soon became weak and winter monsoon b e came strong,the air temperature gradually reduced,the available ra infall was very rich in winter season,and the frequency of climate undula tion increased t oo,the interval time of t he recently cold phase and the warm or hot phase beca me shorter.The record s of the carbon and oxygen isotopes fro m the stalagmite reveal the last two c old or cool events during the late sta ge of the last glac ial period,in which their ages of the coldest deep valley are(15440±13 0)a(H1)and(11910±70)a(YD),respectively,at the same time the b orderline age of the termination I during the last glacial period is confirmed to be(11350±70)a through the precisely dating ages o f TIMS-U series from the stalagmites in Dongge Cave.And it is confirmed that the cold events th at are in correspondence w ith the Heinrich cold events H1and Younger Drays eve nt in the North Atla ntic Ocean exist in the East Asian mon soon climate region of South China during the last glacial period.The p aleo-monsoon circulating current changes in the area of Libo reflected t hat the East Asian summer monsoo n changed fr om weak to strong and then from strong to weak,the available rainf all was from minor to much more and then from m ore to little and from little to more a gain,and the air temperature was fro m the low(or cold)to high(or ho t)and from high to low again.The paleo-monsoon circulating current changes i n this area are clearly affected by the climate oscillation of the North Atl ant ic Ocean,and indicate that they h ave well teleconnection with the paleoclima t ic change occurred in the North pole region.
出处
《地球化学》
CAS
CSCD
北大核心
2004年第1期65-74,共10页
Geochimica
基金
IGCP-448国际对比项目
攀登特别资助项目(2000-026)
国家自然科学基金(40152002)
关键词
古气候环境
高分辨率
石笋
TIMS年龄
stalagmite
TIMS-U seri es dating ag e
high resolution
paleoclimatic e nvironment
Dongge Cave
Guizho u Province
