We describe the last glaciation climatic history Marine Isotope Stage(MIS, 2-4) from 66.7 ka to 14.5 ka in Hexigten, northeast Inner Mongolia, North China. The climate of the region experienced frequent and significan...We describe the last glaciation climatic history Marine Isotope Stage(MIS, 2-4) from 66.7 ka to 14.5 ka in Hexigten, northeast Inner Mongolia, North China. The climate of the region experienced frequent and significant fluctuations between dry-cold and less dry-cold during the late MIS4. The climate was generally warm and humid during early MIS3(MIS3 c) and late MIS3(MIS3 a), whereas it was cold and dry in middle MIS3(MIS3 b) and during MIS2. In this study, the cold and dry conditions were correlated with a stronger East Asian winter monsoon and strong dune activity; whereas, warm and humid conditions were related to a stronger East Asian summer monsoon(EASM) and weak dune activity. This study establishes six distinct dry and cold intervals during the last glacial period(66.7-14.5 ka) based on optically stimulated luminescence data, multi-proxies record(magnetic susceptibility, grain size analysis, Rb/Sr, SiO2/TiO2) and chemical index of alteration(CIA). The last glacial period may be correlated with Heinrich events 1 to 6 which were further confirmed by comparison with the Hulu cave stalagmites and Greenland ice core records. It is concluded that the study area was substantially affected by the EASM, as compared with the loess-desert transition zone of the Chinese Loess Plateau, especially in MIS3 c and suggested that the East Asian monsoon played a pivotal role in the last glacial period climate and dune activity.展开更多
The ＂Old Red Sand＂ is widely distributed along the coast of Fujian Province, China. Most studies have been carried out from as- pects of the origin, age and laterization of the ＂Old Red Sand＂, but this paper focus...The ＂Old Red Sand＂ is widely distributed along the coast of Fujian Province, China. Most studies have been carried out from as- pects of the origin, age and laterization of the ＂Old Red Sand＂, but this paper focused on reconstructing the history of the Asian Winter Monsoon change. On the basis of granulometric analysis of high-resohition samples, we have obtained environmental sen- sitive grain size component （ESGSC） from the Qingfeng （QF） profile by using the grain size-standard deviation method, which proves that the selected ESGSC is an important climate proxy. The mean grain size of this ESGSC could be used to reconstruct the East Asian Winter Monsoon （EAWM） intensity. As such, the history of the EAWM change since 44.0 ka reconstructed here reveals three main phases based on chronology dates of previous researches： （1） 44.0-25.5 ka B.P., the EAWM is relatively weak but increases gradually with fluctuations; （2） 25.5-15.5 ka B.P., relatively strong with high frequency fluctuations; （3） 15.5-7.1 ka B.P., with a weaker winter monsoon, but during 11-10 ka B.P. is remarkably enhanced. The EAWM recorded by mean grain size of the two neighboring sections have a better repeatability, so the millennial scales oscillation should be a reliable signal of the EAWM intensity. The climate recorded by ESGSC of the QF ＂Old Red Sand＂ compared to 6-80 of Huhi Cave stalagmites and Greenland GISP2 ice cores shows a good consistency, especially in detail, the YD event and four Heinrich events are all recorded, but the signal of D-O cycles was relatively weak.展开更多
基金supported by the Research Fund for Hexigten Global Geopark(Grant No.62932014004)Specialized Fund for Fundamental Research Program of China University of Geosciences,Beijing(Grant No.2011YYL016)+1 种基金the Specialized Fund for Public Welfare Industry,Ministry of Land and Resources of China(Grant No.201211077-3)the Specialized Research Fund for the Doctoral Program of Higher Education of China(for PhD supervisors,Grant No.20110022110005)
文摘We describe the last glaciation climatic history Marine Isotope Stage(MIS, 2-4) from 66.7 ka to 14.5 ka in Hexigten, northeast Inner Mongolia, North China. The climate of the region experienced frequent and significant fluctuations between dry-cold and less dry-cold during the late MIS4. The climate was generally warm and humid during early MIS3(MIS3 c) and late MIS3(MIS3 a), whereas it was cold and dry in middle MIS3(MIS3 b) and during MIS2. In this study, the cold and dry conditions were correlated with a stronger East Asian winter monsoon and strong dune activity; whereas, warm and humid conditions were related to a stronger East Asian summer monsoon(EASM) and weak dune activity. This study establishes six distinct dry and cold intervals during the last glacial period(66.7-14.5 ka) based on optically stimulated luminescence data, multi-proxies record(magnetic susceptibility, grain size analysis, Rb/Sr, SiO2/TiO2) and chemical index of alteration(CIA). The last glacial period may be correlated with Heinrich events 1 to 6 which were further confirmed by comparison with the Hulu cave stalagmites and Greenland ice core records. It is concluded that the study area was substantially affected by the EASM, as compared with the loess-desert transition zone of the Chinese Loess Plateau, especially in MIS3 c and suggested that the East Asian monsoon played a pivotal role in the last glacial period climate and dune activity.
基金supported by the National Natural Science Foundation of China(Grant No.41271031)the Open Foundation of State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,CAS(Grant No.SKLLQG1113)
文摘The ＂Old Red Sand＂ is widely distributed along the coast of Fujian Province, China. Most studies have been carried out from as- pects of the origin, age and laterization of the ＂Old Red Sand＂, but this paper focused on reconstructing the history of the Asian Winter Monsoon change. On the basis of granulometric analysis of high-resohition samples, we have obtained environmental sen- sitive grain size component （ESGSC） from the Qingfeng （QF） profile by using the grain size-standard deviation method, which proves that the selected ESGSC is an important climate proxy. The mean grain size of this ESGSC could be used to reconstruct the East Asian Winter Monsoon （EAWM） intensity. As such, the history of the EAWM change since 44.0 ka reconstructed here reveals three main phases based on chronology dates of previous researches： （1） 44.0-25.5 ka B.P., the EAWM is relatively weak but increases gradually with fluctuations; （2） 25.5-15.5 ka B.P., relatively strong with high frequency fluctuations; （3） 15.5-7.1 ka B.P., with a weaker winter monsoon, but during 11-10 ka B.P. is remarkably enhanced. The EAWM recorded by mean grain size of the two neighboring sections have a better repeatability, so the millennial scales oscillation should be a reliable signal of the EAWM intensity. The climate recorded by ESGSC of the QF ＂Old Red Sand＂ compared to 6-80 of Huhi Cave stalagmites and Greenland GISP2 ice cores shows a good consistency, especially in detail, the YD event and four Heinrich events are all recorded, but the signal of D-O cycles was relatively weak.
