内蒙古四子王旗大井坡第四纪冰碛物的发现及古气候意义

发布时间：2018-04-05 14:32

本文选题：冰碛物　切入点：寒潮　出处：《中国地质大学(北京)》2017年硕士论文

【摘要】：第四纪古冰川遗迹是研究当时气候变动最直观的标志和证据,通过对古冰川遗迹分布位置、年龄和地貌特征的研究,可以反演第四纪期间的气候环境变化,第四纪气候环境的变化与人类的关系是密不可分的,研究第四纪冰川能够使人类更深入地掌握世界气候的演化史和预测未来的气候环境变化,为人类与地球能够建立更加和谐的依存关系做出巨大贡献。本文在四子王旗大井坡地区共识别出三条冰碛垄,采用了统计分析冰碛物组成、光释光(OSL)测年技术、孢粉化石统计分析和对各冰期进行区域对比等研究手段。通过学习和整理地质前辈们的研究成果,本文深入分析四子王旗大井坡地区冰川期次和成因与气候变化之间的关系,探讨内蒙古大井坡地区第四纪期间古冰川遗迹的分布情况和成因机制的重要影响因素,综合以上资料论文取得如下认识:1.依据野外资料与实验结果可以认别出研究区内共三条冰碛垄,第一条冰碛垄主要由石英岩砾石组成,其年龄为292.2±16.3ka,当时的气候为针叶林-草原,气候温凉偏干,对应氧同位素MIS8阶段,为故乡冰期第二阶段(倒数第二次冰期);第二条冰碛垄主要由白云母花岗岩砾石组成,其年龄为127.3±6.2ka,当时的气候为针叶林-草原,气候温凉略干,对应氧同位素MIS6阶段,为故乡冰期第三阶段(倒数第二次冰期);第三条冰碛垄主要由灰岩砾石组成,其年龄为70.4±3.7ka,当时的气候为草原,气候温凉略干,对应氧同位素MIS4阶段,为末次冰期。2.综合研究大青山北坡地区的古冰川遗迹年代特征、形态特征以及分布特征,可以证明第四纪大青山北坡发生过规模较大的冰川作用,其冰川性质可能属于大陆型冰川,有着分布面积广、沉积物厚度大的特点,这对于进一步研究第四纪期间的古气候环境及其变化规律有着重大意义。3.论文研究认为,影响中国东部低山丘陵区古冰川活动范围的最主要因素是古寒潮活动,古寒潮活动的影响范围,基本上就是古冰川活动和冰缘环境的分布范围,这可能是近年来许多研究者在我国南方能找到古冰川活动遗迹的原因。不能用简单的雪线高度(西部冰川成因理论)来判定是否存在古冰川遗迹,频繁的寒潮活动使气温保持在有利于冰川发育的条件,是完全可能的。
[Abstract]:Quaternary ancient glacial remains are the most intuitionistic signs and evidence to study the climate change at that time. By studying the location, age and geomorphological characteristics of ancient glacier remains, the climatic and environmental changes during the Quaternary period can be inversed.The change of Quaternary climate and environment is inextricably related to human beings. The study of Quaternary glaciers can enable people to have a deeper understanding of the history of the world's climate evolution and predict future climatic and environmental changes.To make a great contribution to the establishment of a more harmonious relationship between human beings and the earth.In this paper, three moraine ridges have been identified in Dagingpo area of Siziwang Banner. Statistical analysis of moraine composition, OSL dating technique, statistical analysis of sporopollen fossils and regional comparison of various glacial ages have been used in this paper.By studying and sorting out the research achievements of the geological predecessors, this paper deeply analyzes the relationship between the glaciation and genesis and climate change in the Dagingpo area of Siziwang Banner.The distribution of ancient glacial remains during the Quaternary and the important influencing factors of the genetic mechanism in the Dagingpo area of Inner Mongolia were discussed.Based on field data and experimental results, three moraine ridges were identified in the study area. The first moraine ridge was mainly composed of quartzite gravel with an age of 292.2 卤16.3 ka.The climate was coniferous and steppe at that time, and the climate was warm and dry.Corresponding to the oxygen isotope MIS8 stage, the second stage of the native glacial age (the penultimate ice age) and the second moraine ridge are mainly composed of Muscovite granite gravel, whose age is 127.3 卤6.2 ka.The climate at that time was coniferous forest and grassland, and the climate was warm and cool and slightly dry.The corresponding oxygen isotope MIS6 stage is the third stage of the native glacial age (the penultimate second glacial period), the third moraine ridge is mainly composed of limestone gravel, its age is 70.4 卤3.7ka.The climate at that time was steppe, the climate was mild and dry, corresponding to the MIS4 stage of oxygen isotope.It is the last glacial age.A comprehensive study of the age, morphology and distribution of ancient glacial remains in the northern slope of Daqingshan shows that a large scale glaciation occurred on the northern slope of Daqingshan in the Quaternary, and that the glacier may be a continental glacier.It is of great significance to further study the paleoclimate environment and its variation law during the Quaternary period.The study shows that the most important factor affecting the range of ancient glacier activity in the low hilly region of eastern China is the paleogrial wave activity, and the influence range of the paleo-cold wave activity is basically the distribution range of the paleo-glacial activity and the ice margin environment.This may be the reason why many researchers can find ancient glacier activity in southern China in recent years.The existence of ancient glacier remains can not be determined by the simple snow line height (the theory of glacier genesis in the west). It is completely possible that the temperature can be kept in favorable conditions for glacier development due to frequent cold wave activity.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P532

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