Elemental geochemical characteristics of Lower—Middle Permian mudstones in Taikang Uplift, southern North China Basin: implications for the FOUR-PALEO conditions

摘要: The paleo-sedimentary environment can be restored qualitatively or semiqualitatively using elements combinations of that are sensitive to the depositional environment. Through analysis and testing main elements, trace rare earth twenty-one Lower—Middle Permian coal-bearing strata mudstone samples in Taikang Uplift, southern North China Basin, this study explored FOUR-PALEO conditions (paleo-water depth, paleo-redox conditions, paleoclimate paleo-provenance). La Co contents indicate water depth northern margin Basin became gradually shallower during period. According U/Th, Uau, V/Cr, Ni/Co V/Sc ratios, it is known section basin an oxidizing environment, oxidation enhanced from Taiyuan Formation Lower Shihezi Formation. Paleoclimate bivariate plot diagrams C-value Sr/Cu versus Ga/Rb shows Uplift was characterized by a warm arid climate period humid Shanxi transitional arid. CIA, PIA, ICV, Th/U K/Rb reflect tectonic settings source area. From Formation, CIA PIA increase, ICV decreases, indicating chemical weathering transition area, frequent change sudden Additionally, provenance discriminant function, Zr/Sc-Th/Sr, REEs Th Hf-Co, Hf La/Th ZREE vs. La/Yb type associated with magmatic differentiation. Moreover, diagrams, consisting K2O/Na2O SiO2, La-Th-Sc, Th-Sc-Zr/10 Th-Co-Zr/10, suggest mudstones Lower-Middle were deposited active continental settings.