Major element characteristics of sandstones and provenance analysis of basins

Abstract：Major element characteristics of sandstones from different kinds of basin are a function of particular provenance types and tectonic environments, and provenance analysis of basins may be performed using major element diagrams. Based on previous research, the authors selectively collected 569 major element data of sandstones with different tectonic environments, which are divided into 70 sets of average values. According to related references, the authors identify five kinds of provenances and tectonic environments: craton interior, continental arc, collisional orogenic belts, continental island arc and oceanic island arc. Based on an integrated analysis of the correlation between major elements in the sandstones collected, by using the correlation coefficients of the whole and major elements in sandstones derived from different provenances, the authors obtain five assemblages of major element oxides: SiO2, Al2O3+FeOT, K2O+Na2O, MnO+TiO2 and MgO+CaO, and then a triangular discriminant diagram of (Al2O3+FeOT)/(Na2O+K2O)-SiO2/(MnO+TiO2)/100-MgO+CaO is established. Two discriminant functions, F1 and F2, which are correlated with SiO2, CaO, MgO, FeOT, K2O, MnO, Al2O3, Na2O and TiO2, are gained by a discriminant function analysis of the collected data and a discriminant diagram of tectonic environments for two-variable (F1 and F2) provenances is established. According to the main elements in detrital grains of sandstones, the contents of quartz, feldspar and basic lithic minerals in the sandstones are analyzed using the molar percentages of the major elements to constrain the provenances. The constructed Qel-Fel-Lel diagram not only reflects the discrimination of the provenance and tectonic environments of sandstone by major elements but also approximately shows the composition of fragments in sandstones in related environments.