End member model analysis of grain size for the loess in Linfen Basin, China

In order to understand the grain size distribution pattern of the loess sediments and its bearing on climatic changes in the Linfen Basin on the southeastern margin of the Loess Plateau, the method of Parametric End-member Modeling was used to analyze the grain size data of the loess sediments through extraction of the grain-size fraction sensitive to climate changes. According to Shepard’s classification, the Loess-paleosol sequence in the Linfen Basin is mainly composed of silt and clayey silt. Three general Weibull distribution end members (EM) are recognized. Our results suggest that the EM1 may indicate the product of weathering and pedogenesis of loess under the influence of summer monsoon in the East Asia, while the EM2 indicate the remotely sourced dust by the high-altitude airflow under the control of the westerly belt. The EM3 represents near source dust brought by the East Asia winter monsoon and short-term dust storms in winter. Through the correlation with OSL results, grain size end-member of the loess, magnetic susceptibility and SPECMAP data, it is found that the oxygen isotope of Linfen Basin is consistent with that of SPECMAP, indicating that the climate evolution of the Basin is controlled by global ice amount. However, the internal fluctuation within each stage shows regional features.