Geochemical and Clay-Size Minerals Evidence for the Provenance of LQC Loess Deposits in the Central Shandong, Northern China

Abstract

The identification of the Shandong loess provenance adjacent to the floodplain of the Yellow River external the Loess Plateau is very important for revealing the path of dust accumulation and paleoenvironment, which has aroused widespread concern. In this study, the clay-size(< 5μm) minerals and major elements composition of bulk samples and of two grain-size fractions (< 20μm and 20~63μm) were analyzed in order to determine the provenance of the LongQiaoCun(LQC) loess in the Central Shandong based on comparisons with loess from the Chinese Loess Plateau and with Yellow River sediments. Statistical analysis of the sedimentary clay-size minerals reveals that LQC loess deposits in the Central Shandong adjacent to the floodplain of the Yellow River were not blown directly from the northern deserts as is the case of loess deposits in the Chinese Loess Plateau. and the Yellow River sediments may be related to erosion from the Loess Plateau. The difference in relatively immobile major element ratios of TiO2 /Al 2O3 and K 2O/Al 2O3 of the < 20μm and 20 ~ 63μm fractions affirm that sediments exposed during glacial periods in the North China fluvial plain, including the floodplain of Yellow River, were the major dust source as the statistical analysis of the sedimentary clay-size minerals has concluded.