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对中国黄土标准剖面——洛川黄土剖面之下的上新世红黏土进行了沉积特征和磁性地层学的研究,结果表明洛川红黏土堆积于约2.6~3.2 MaBP期间,从而确定世界惟一的黄土类地质公园的风尘开始堆积的年代约为3.2 MaBP。古气候替代性指标磁化率和粒度的分析表明,洛川风尘堆积序列记录了上新世到第四纪古气候的重大转型。

The North China and the neighbouring Mongolia in Asian Interior is characterized by extremely dry climate, resulted in one of the world＇s major dust emission centres. Deciphering the source region of Asian dust is critical for revealing the mechanism of the dust production, interpreting the paleo-environrnental records of eolian deposits, predicting the overall environmental effects of dust, and setting the strategies for the control of contemporary dust storms. This paper summarizes the geochemical methods applied to the source tracing of Asian dust. Nd-Sr isotopes were the most extensively studied source tracer of Asian dust and have been successfully applied in many cases. Geochemistry of detrital monomineral shows great theoretical advantages in source tracing and deserves further studies. The short-range transportation of Chinese loess with direction similar to that of the prevailing near surface wind is revealed. Source tracing also shows that the Asian dust has two ultimate material sources from the northern margin of the Tibetan Plateau and the Central Asian Orogen, which confirms the importance of mountain processes in the production of silt eolian particles. Based on the recent progresses on the source tracing of Asian dust, discussions are expanded on the natural background of Asian dust storms and potential anthropogenic influence, the materials evolution of the source regions of Asian dust and its relationships with climate changes and Tibetan uplift, and the role of Tibetan uplift in the Asian dust system.

The geomorphic evolution of northwestern China during the Cenozoic has been a subject of much geological interest because of its link with the uplift of the Himalayan-Tibetan complex. Much information about these changes is recoverable from the sedimentary sequences of the region. We report here on the thick eolian deposits mantling the Huajialing Mountains, a relatively flat mountain range in the western Loess Plateau. Correlation of magnetic susceptibility stratigraphy with the QA-I Miocene eolian sequence dates a 134.7 m section （NL-VII） for the interval from 18.7 to 11.8 Ma, as confirmed by micromammalian fossils. These eolian deposits demonstrate a much wider distribution of the Miocene eolian deposits, and also indicate that the topography contrasts in the western Loess Plateau, including the uplifts of the Huajialing Mountains and the bedrock highlands in the Qinan region, were formed by the early Miocene. The near-continuous Miocene eolian sequence from 18.7 to 11.8 Ma indicates that the substratum of Huajialing had not experienced any intense tectonic changes during this time interval, which suggests further, the relative tectonic stability of the nearby Tibetan Plateau.