Geochemical signatures and provenance analysis of the Upper Permian to Lower Triassic argillaceous rocks in the Yiluo Basin,western Henan

The sediment filling and evolution of the Yiluo Basin during the Late Permian to the Triassic resulted from the tectonic movement in the Qinlin orogen and the North China craton, and the provenance analysis is interpreted as one of the important tools for revealing the basin-mountain coupling processes. The geochemical signatures and provenance analysis are treated in the present paper for the Upper Permian to Lower Triassic argillaceous rocks from the Yiluo Basin, western Henan. The argillaceous rocks in the Yiluo Basin are characterized by the LREE enrichment, HREE depletion, moderate Eu anomaly and slight Ce depletion, indicating a dominant upper crust origin, with the mixtures of a small amount of ancient basement complexes in the Sunjiagou Formation. The tectonic settings of the provenances in the study area have gone through the transition from the passive continental margin (the lower member of the Sunjiagou Formation) through the active continental margin (the upper member of the Sunjiagou Formation and the Liujiagou Formation) to the continental island arc (Heshanggou Formation). The Qinlin orogen and the North China craton are believed to be the key provenances for the Yiluo Basin. The cratonic origin during the deposition of the lower member of the Sunjiagou Formation and Qinling origin after the deposition of the Tumen member of the Sunjiagou Formation in the Yiluo Basin indicate the basement uplift on the southern margin of the North China craton, and the tectonic evolution from the passive continental margin to the "arc-continent" collision and uplift of the Qinling block. The results of research in this study are helpful to the understanding of the coupling processes of the southern North China Basin and its surrounding orogenic zones.