Abstract:

 REE of the Upper-Jurassic and Cretaceous argillaceous rocks from the western Sichuan foreland basin were tested and analyzed, and the geochemical characteristics of REE, sedimentary environments, provenance properties and tectonic settings of provenances of argillaceous rocks from the research area were also discussed. Current study shows that tectonic provinces and sedimentary environments have a control to a certain extent on the REE characteristics and sedimentary differentiation of REE of argillaceous rocks, and that REE characteristics of argillaceous rocks were mainly reconstructed to a certain extent by sedimentation. Although the testing samples present dominantly significant LREE enrichment, lowabundance HREE and negative Eu anomaly, most of them display obviously negative Ce anomaly. Results suggest that all argillaceous rocks have high differentiation degree and stably average differentiation degree from Upper Jurassic to Upper Cretaceous. A sedimentary environmental model characterized by overall oxidation and local deoxidation was suggested for the argillaceous rocks in research area. Source rocks are mainly sedimentary rocks and granitic rocks, probably with a few locallyinvolved basalt components. Analysis of provenances of argillaceous rocks show that the tectonic setting is mainly continental island arc and partly passive continental margin.

Key words: western Sichuan, foreland basin, Upper-Jurassic to Cretaceous, argillaceous rock, rare earth element, sedimentary environment, provenance, tectonic setting