【作者】 王勇；

【导师】 潘保田；

【作者基本信息】 兰州大学 ， 自然地理学， 2006， 博士

【摘要】 地球系统科学是近年来地学研究的热点和趋势之一。地球各圈层间的相互作用是地球系统科学的核心和研究对象。新生代以来地球各圈层相互作用的研究表明，构造运动是各圈层相互作用中的一个重要因素，对地球各圈层相互作用的研究往往是以构造运动作为切入点的。 青藏高原隆升是新生代地质历史上最为重要的构造运动事件，对全球环境变化起着重要的作用。青藏高原隆升过程及其资源环境效应一直是国内外地学界研究的热点问题。青藏高原及其周缘地区是地球表层各圈层相互作用研究的天然实验场。为了深入的认识高原隆升及其环境效应，我们选择了最近1.2Ma以来青藏高原的构造运动及其对东亚地区(主要是我国)环境的影响来探讨地球表层各圈层之间的相互联系。 结合前人的工作和我们最近对青藏高原东缘渭河阶地发育的研究，对最近1.2Ma以来青藏高原的隆升过程进行了一个系统的初步总结。高原最近1.2Ma以来的隆升过程主要经过了“昆黄运动”和“共和运动”。这两次构造运动对东亚地表的其他圈层产生了重要的影响。其中，“昆黄运动”历时较长，可以分为三个亚阶段，分别发生在1.2—1.1Ma，0.9—0.8Ma和0.6Ma。渭河上游河流阶地上覆黄土的磁性地层学研究表明渭河在1.0和0.8Ma发生了强烈下切。从这两级阶地的组成特征，及其和“昆黄运动”的第二阶段存在着时间上的良好吻合等特征，我们认为，渭河上游此时的河流下切代表的地表抬升过程是青藏高原“昆黄运动”在西秦岭地区的区域响应。 对青藏高原东北边缘的祁连山东段中路剖面磁组构的研究是我们进行古大气环流重建研究的工作重点。古风向的代用指标研究显示：1.4Ma以来，祁连山东段地区的古风向存在两个重要的转变时期：一是0.78Ma左右，该区地面主导风向由此前的NW—SE向W—E方向转变；二是古土壤S5(0.5Ma)之后，地面主导风向转为NE—SW。这两次风向的转变和高原在中更新世以来的隆升及全球性的气候变化事件在时间上具有良好的耦合性。这种近地面大气环流的变化很可能是高原隆升和／或气候变化的产物。同时，我们对沙沟剖面的磁组构参数研究揭示出：在西北内陆干旱—半干旱条件下，黄土磁化率指标“失灵”，而受强烈冬季风影响的磁化率各向异性参数(尤其是各向异性度P)却可以较为灵敏的记录环境变化的重要信息。区域和全球气候变化的重要信息都被记录在磁组构参数的变化当中，如250ka区域的强烈干冷化事件和MIS16阶段全球更多还原

【Abstract】 During past decades, the development of earth science indicates that the environmental conditions of earth, including the climate, are determined by physical, chemical, biological, and human interactions that transform and transport materials and energy. Investigations on the interaction or mechanism between these multiple components of the earth system became a hot issue of geosciences field. The tectonic movement/uplift of the lithosphere, as discussed in many investigations, controlled the global environmental change during the whole Cenozoic period on the 10~5-10~7 years time scale. Given this discussion, the tectonic movement/uplift of lithosphere provides a good opportunity for the research of interaction between the complex earth system components. Specifically, our efforts are paid to the recent 1.2Ma when the environment in China changed dramatically. First, also the dominant change of Chinese environment since 1.2Ma B.P. is the tectonic uplift of the Tibetan Plateau (TP). Hence, this lithosphere change is proved to be the trigger and amplifier of the whole system by previous investigations. However, the advance and detail research are limited.Well situated at the eastern margin of the Tibetan Plateau, the geomorphology evolvement of the Weihe River is a promising evidence to record the tectonic uplift events of the TP. The magnetostragraphy study of loess deposited on the river terrace indicated that there were at least two dramatic down-cutting events in the Longxi Basin during 1.0-0.8Ma. The analysis of river terrace characters and the temporal coincidence of records in other regions confirm our proposal that these two down-cutting events of Weihe River are tectonic driven. Integrated our results with other intensively studied records in and around the Tibetan Plateau from 1.2Ma; we suggest two tectonic uplift stages of TP with the first one during 1.2-0.6Ma and the second one during 0.2-0.15Ma. Moreover, the first stage can be divided into three sub-stages: l)1.2-1.1Ma, characterized by the down-cutting of the Yellow river in Jishi Gorge, 2)0.9-0.8Ma, the main phase of the tectonic uplift, and 3) 0.6Ma.Before attempting a systematic discussion of the interactions between lithosphere, atmosphere, hydrosphere, and biosphere of China, the evolution of every sphere since 1.2Ma are considered. The magnetic fabric-based reconstruction of paleowind direction in the northeastern flank of Qilian Mountains reveals the near surface air circulation changes, which are dictated by the East Asian Monsoon, in ~0.78Ma (from NW-SE to W-E) and 0.5Ma (a NE-SW dominant direction established). Time of the first paleowind direction change is temporal related to the end time of the major tectonic uplift of TP casually, which may suggest the affection of tectonic uplift on the atmospheric circulation. Studies on the loess magnetic fabric and magnetic susceptibility (MS) in semi-arid region, such as northeastern flank of Qilian Mountains,更多还原