【作者】 傅建利；

【导师】 蒋复初；

【作者基本信息】 中国地质科学院 ， 第四纪地质学， 2009， 博士

【摘要】 本文主要建立了黄河三门峡段的湖积台地和河流阶地序列,重建了研究区2.0 MaB.P.以来的古气候演变过程,在此基础上,探讨了研究区河湖地貌发育和环境演变过程对构造运动和气候变化的响应关系。野外考察发现,研究区发育多级湖积台地和河流阶地。基于大量阶地剖面的测量,典型阶地系统样品采集,并通过磁性地层、ESR和OSL测年等系统的年代学研究,确定研究区共发育九级湖积台地和河流阶地,分别形成于2.0 Ma B.P.（T9）,1.62 Ma B.P.（T8）,1.25Ma B.R（T7）,0.87Ma B.P（T6）,0.63Ma B.P.（T5）,0.25Ma B.P.（T4）,0.15Ma B.P.（T3）,86～63Ka B.P.和41～22Ka B.P.（T1）。通过对三门峡盆地望原台地和垣曲盆地原土坪台地粒度特征的分析表明,两个台地剖面均由湖相沉积、湖滨相沉积和风成沉积构成,记录了一个构造抬升,由水下转变为气下环境的连续沉积过程。望原台地两次沉积转型发生于2.21Ma B.P.和2.00Ma B.P,原土坪台地发生于1.84Ma B.P.和1.62Ma B.P.。望原剖面和原土坪剖面黄土粒度特征显示,2.0Ma B.P.以来冬季风整体增强,并且存在1.83～0.87Ma B.P.和0.87Ma B.P.以来两个逐渐增强的阶段,冬季风总体变化特征与全球大陆冰量变化相一致,说明研究区气候记录是对全球气候变化的响应,并且全球冰量变化是研究区古气候演化的驱动因素。望原剖面和原土坪剖面黄土记录的1.83Ma B.P.1、1.65Ma B.P、1.15Ma B.P、0.87MaB.P.、0.66Ma B.P.和0.19 Ma B.P.前后的气候转变期与青藏高原快速隆升阶段存在较好的耦合关系,表明青藏高原阶段性隆升可能是影响研究区古气候演变的主要因素。黄河三门峡段台地（阶地）的形成年代、冬季风演化阶段与全球冰量变化和青藏高原快速隆升时段的耦合关系表明,研究区地貌发育和古气候演变主要受以青藏高原隆升为主体的区域构造运动控制。望原黄土剖面和原土坪黄土剖面L₁₅、L₉、L₆和L₂黄土层记录的4次＞63μm颗粒含量突然增加的环境事件,时间上可与青藏高原“昆黄运动”和‘“共和运动”的主要隆起幕相对应,可能指示了区域的构造抬升。更多还原

【Abstract】 Plenty of structure and climate information was concluded by the development of Fluvio-lacustrine Landform. There are abroad distributed Fluvio-lacustrine physiognomies in the Yellow River basin between Shanxi and Henan which are the right carrier for the research about the dynamic interaction among the formation, climate and surface change of the Earth. So the deeply research of the Yellow River basin in this region is very important for the theoretics and realism.The physiognomic character along the Yellow River between Shanxi and Henan is basin-mountain interphase. Depended on the detailed measurement of terraces within eleven sections in different physiognomic positions, the formation dates of typical terraces and their sequences were established. Based on the analysis of granularity and magnetization rate, the sediment structures of the Wangyuan and Yuantuping terrace were identified, and the evolvement process of paleoclimate and paleoenvironment in the researched area was rebuilt. In the end, the influence of the Fluvio-lacustrine landform development in this region on the responding relationship between tectonic movement and environmental change was discussed.From the field observation, it was found that there are many terraces （river terraces/lacustrine-deposit mesas） in the research region and the terraces are mainly distributed on the sides of the basins. Based on the research of systemic chronology by the optically stimulated luminescence （OSL） dating and electron spin responance （ESR） signal, it was confirmed that there are nine terraces of lacustrine-deposit mesas or river terraces in the area. These terraces were formed sequentially at 2.0 Ma B.P. （T9）, 1.62 Ma B.P. （T8）, 1.25Ma B.P. （T7）, 0.87Ma B.P. （T6）, 0.63Ma B.P. （T5）, 0.25Ma B.P. （T4）, 0.15Ma B.P. （T3）, 86～63Ka B.P. （T2） and 41～22Ka B.P. （T1）.From the character analysis of granularity, it was indicated that the sediment contents of the lacustrine and floodplain deposits in the underlayers of the Wangyuan mesas and Yuantuping terraces were from eolian deposits or resediment of the deposits, and the sediment structure of the terraces from lacustrine to floodplain deposit and then to eolian deposit recorded a tectonic movement, the drop of water level and the sequentially depositing process from water to air. The deposit transfers of Wangyuan mesas were happened at 2.21 Ma B.P. and 2.00Ma B.P., and the transfers of Yuantuping terraces were at 1.84MaB.P. and 1.62Ma B.P..The loess granules of eolian deposit which larger than 32μm showed the intensities of the winter monsoon. The section recording of Wangyuan mesas and Yuantuping terraces indicated that intensities of the winter monsoon from 2.0Ma B.P. were whole enhanced and there were two gradually enhanced phases at 1.83～0.8 7Ma B.P. and 0.87 Ma B.P.The evolutional charactars of the winter monsoon is coupled with the change of the global ice content, which esplained that the paleoclimate of research region had responded to the global climate change, and the change of global ice content was the driving factor of the paleoclimate evolution in this area.From the loess records of Wangyuan and Yuantuping profiles, it was shown that the paleoclimate in these regions was markedly conversed at 1.83Ma B.P. 1(L₂₅/S₂₅), 1.65Ma B.P. (S₂₃/L₂₄), 1.15Ma B.P. (L₁₅/S₁₅), 0.87Ma B.P. （S₈/L₉）, 0.66Ma B.P. （S₅/L₆） and 0.19 Ma B.P. （L₂/S₂）. The change phases and characters of the paleoclimate were consisted with the records of Luochuan loess sections in Loess Plateau. The consistence of the climate change phases in researched region and the eras of the quickly phasic uplift in Tibetan Plateau showed that the phased uplift of Tibetan Plateau is the main factor which influenced the paleoclimate change in the researched area.The coupling relationship among the formation age of the step-like physiognomy of lacustrine-deposit mesas and river terraces between Shanxi and Henan, the evolvement phases of the winter monsoon recorded by loess, the global change phases of ice volume, and the eras of the quickly phased uplift in Tibetan Plateau indicated that the landform development and paleoclimate evolution were mainly controlled by the regional environmental changes and the global climate evolution acted just as trending background.The suddenly increment of loess grains larger than 63μm in the L₁₅, L₉, L₆, and L₂ sections of Wangyuan mesas and Yuantuping terraces indicated four environment events happened. The results showed that there formed some terraces during the environment events in this Yellow River basin, and the age was consisted with the starting times of the uplifts of "Kun-Huang movement" and "Republican movement" in Tibetan Plateau. All of these indicated that the suddenly increment of loess grains larger than 63μm could reflect the regional tectonic movement.更多还原