Based on some changing laws of invariable primary element and trace element (including REE) contents in Wangjiagang, Guangli and Chunliang areas, the sedimento-geochemical features of sandstones from the Fourth Member, Shahejie Formation in the Southern Slope of Dongying Sag were studied in this paper. The majority of the sandstones was feldspathic litharenite and lithic arkose, and the subordinate parts were lithic sandstones and feldspar sandstones. The A-CN-K diagram indicated that the average plagioclase content was higher than the potassium feldspar content in the provenance, which varied from granodioritic rocks to granitic ones (including the relevant gneisses). The sandstones underwent K-metasomatism during weathering processes. The parameters of chemical index of weathering (CIW) and the chemical index of alteration (CIA) suggested that the sandstones in the area might be weatheringed intensely, especially in the Chunliang area. The index of compositional variability (ICV) showed that there might be some first cycle material in the sandstones. In addition,the trace element ratios, such as (La/Yb)N and (La/Lu)N, suggested further that the provenance for the sandstones in the Southern!Slope of Dongying Sag should be a mixed one of granodioritic and granitic (including relevant gneissic) rocks.
Zhang Xin,Zhang Jinliang. SEDIMENTO-GEOCHEMICAL FEATURES OF SANDSTONES FROM THE FOURTH MEMBER,SHAHEJIE FORMATION IN THE SOUTHERN SLOPE OF DONGYING SAG[J]. Chinese Journal of Geology, 2007, (2): 303-318.