The Characteristics of Rare Earth Elements of Red Mudstones in the Lower Part of the Fourth Member of Shahejie Formation in Dongying Depression and its Geological Significance

Abstract

The comprehensive analysis of rare earth elements (REEs) of red mudstones in the lower part of the fourth member of Shahejie Formation (S4) in Dongying Depression shows that the red mudstones in the lower S4 of Dongying Depression originate from multi-sources. Red mudstones can be classified into three major types based on the characteristics of their sedimentary structures, which are closely relevant to REEs of red mudstones. The three types of red mudstones are obviously different in distribution: the first type is close to eolian deposits, indicating their relevance to wind action in formation; the second type, partly similar to the first type, has obvious differences with the first type, which can be deduced that it is formed through secondary transformation; the third type embraces the alluvial characteristics, suggesting its good inheritance of the surrounding parent rocks in the distribution of REEs.