干旱区生态环境知识资源中心

In order to investigate the geochemical and palaeo-climate significance of the 56 submember of majiagou formation, mineral assemblage and inorganic geochemistry features of SJ1 well were particular analyzed by X-ray diffraction and SEM characterization. The result of trace and major elements about mudstone interlayer samples showed that the mineral assemblage of clay in this area was mainly illite and chlorite, and these two complement were relatively complementd from each other. Mn, Sr, P, Cu, Rb/Sr, Sr/Cu, Fe/Mn, (Fe+Al)/(Ca+Mg),V/(V+Ni) and Cu/Zn had the simialr variation tendencies on the vertical section. Upper and middle cycle could be divided into five and four sub-cycles, respectively. The analysis on clay minerals and chemical elements revealed that the paleoclimate of the 5(6) Submember of Majiagou was formed in semi-arid and arid with deepwater and reducing environment. The palaeo-climate of upper cycle was more arid than the middle, and it had lower frequency on the secondary wet-arid change, which was regarded to be conducive to the formation of potassium.