兰州大学机构库 >资源环境学院
河西地区末次冰期旋回气候与环境变化研究
Alternative TitleA study on climate and Environmental changes in Hexi area during the last Glacial-Interglacial cycle
于永涛
Thesis Advisor杨太保
2002-07-01
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword河西干旱区 气候不稳定性 环境变化
Abstract和中国西北干旱区的其它两个环境巨系统——青藏高原和东亚季风敏感区的黄土高原相比,河西走廊及其以北的河西干旱区是研究程度最不充分的,尤其缺乏能用于晚更新世气候、环境重建的沉积连续的高分辨率记录。高台盐池位于中段走廊中段,沉积速率高,是季风-沙漠-黄土耦合环境系统的最敏感的结合部,因此,更好地了解末次冰期旋回河西地区经历了怎样的气候与环境变化,弄清该地区的气候波动在何种程度上类似于记录在其它地质档案和相关地区的变化,查明晚更新世快速气候变化的驱动力和内部相互作用机制,具有非常重要的科学意义。 在结合古地磁事件年代学和常规碳-14测年的基础上建立的高台GT40孔磁化率-时间标度曲线在末次间冰期、末次冰期和全新世三个时段都表现出与较快的波动,尤其以MIS3阶段晚期和末次盛冰期为最。研究表明,格陵兰冰芯末次冰期最具代表性的H事件和D/O旋回以及冰阶-间冰阶等气候不稳定性在河西干旱区,甚至整个干旱亚洲都存在,而且可以扩展到末次间冰期和全新世。其中,末次间冰期和全新世的快速气候颤动大致以存1ka和2ka为主控周期;准万年贯穿周期末次冰期,而在其早晚阶段则分别以2ka和急剧增加的百年小幅周期为特色。 通过与其他气候记录体系和地点的对比,我们发现,我国西北干旱区冰期和间冰期气候存在两种不同的变化模式,冰期我国气候变化通过西风环流或蒙古高压与北半球高纬地区存在密切联系,气候变化主要受控于大陆冰盖的变化,而间冰期气候通过东亚季风环流与西太平洋暖池等低纬海洋联系更为密切,同时至少存在赤道太平洋、青藏高原和北半球高纬冰盖三个相对分散的气候变化驱动源,它们共同影响敏感的亚洲干旱区的气候变迁模式,但最终还是受控于北半球高纬冰盖系统和北大西洋地区。
Other AbstractCompared with other two mega-environmental systems in the arid northwestern China—the high Tibetan Plateau and the East Asian monsoon-susceptible loess Plateau, the arid Hexi region is least studied, especially lacking of continuous high-resolution sediment sequences for late Pleistocene climate and environmental reconstruction. Yanchi Playa, where two parallel drilling cores are retrieved, enjoying very high sedimentation rate, is located in the middle of the Hexi Corridor that is the critical connecting part of the monsoon-desert-loess coupled environmental system. It is of great scientific implication for us to better understand what kind of climatic and environmental changes the arid Hexi region has experienced over the last Glacial-Interglacial cycle, to what extent does this region mirror variations in climate documented in other geological archives and relating localities, and what’s the driving forces and the internal interaction mechanisms that account for the late Pleistocene global climate fluctuations. GT40 magnetic susceptibility-age scale, combined magnetic susceptibility and soil color index, with timescale established on the basis of paleomagnetic event chronology and conventional carbon-14 dating, shows rapid fluntations both during the last glaciation, and in the last interglacial and in the Holocene period, especially during late MIS3 and the Last Glacial Maximum(LGM). Our reseach suggests that various scales of climatic instability, characterized by Northern Hemispheric Heinrich events,D/O cycles and stadial-interstadial oscillations, not only exists over the last glaciation in arid Hexi Area, but also may have expanded into the last interglacial and the Holocene over the entire arid central Asia. Climate flickering changes over the last interglacial and the Holocene is dominated by the 1ka and 2ka periodicity, while the quasi-10ka periodicity penetrates the whole last glaciation and there is a distinguished transition from 2ka in its early stage to enhanced decadal-scale fluctuations in its late stage. By comparing our results with other climate change recording systems and working localities, we found that climate patterns in the arid northwestern China may be very much different in glacial and interglacial period. In the cold glacical, its changing climate is controlled mainly by the land ice-volume variations in the North Hemispheric high latitudes, through highly intensified Westerly circulation and/or much stronger Mongoli...
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Language中文
Document Type学位论文
Identifierhttp://ir.lzu.edu.cn/handle/262010/239819
Collection资源环境学院
Recommended Citation
GB/T 7714
于永涛. 河西地区末次冰期旋回气候与环境变化研究[D]. 兰州. 兰州大学,2002.
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