Influence of tectonic uplift of the Qinling Mountains on the paleoclimatic environment of surrounding areas: Insights from loess–paleosol sequences, Weihe Basin, central China

Abstract

The southern edge of the Chinese Loess Plateau affected by the stepwise uplift of the Qinling Mountains is a transitional climatic area between the different climatic environments and sedimentary characteristics to the north and south sides of the Qinling Mountains. The study of different Quaternary loess deposits in this region is conducive to improving our understanding of the micro-scale climatic effects of tectonic developments. Here, we use a series of experimental methods on a well-preserved loess–paleosol sequence in the South Jingyang Plateau to obtain proxy data, including grain-size, magnetic susceptibility, loss on ignition, and geochemical elemental. Changes in grain-size, magnetic susceptibility and loss on ignition indicate that the East Asian monsoon has undergone significant changes due to the continued global cooling and mid-Pleistocene climate transition during the deposition process of XSD loess, i.e., the intensities of the winter and summer monsoons were simultaneously enhanced. Elemental correlations and factor analysis indicate the sedimentary environment and provenance of the deposits, while elemental enrichment and element ratios, including Si/Ti, Al/Ti, Rb/Sr and Zr/Rb, are consistent with changes in the intensity of pedogenic and of the East Asian monsoon as reflected by climate proxies, illustrating that XRF core scanning analysis technology has great potential in the field of Quaternary environmental changes of loess. Furthermore, the stepwise uplift of the Qinling Mountains, which has blocked the winter and summer monsoons to a certain extent, has had a significant impact on the relative degree of loess accumulation and pedogenic in the northern piedmont, southern piedmont and intermontane basin of the Qinling Mountains and also appears to have promoted settlement by early humans. Hence, the study of paleoclimate in areas of active tectonic movement has the potential to promote our understanding of micro-scale climate change in this region in the future.