陕西洛川黄土剖面中的稀土元素

The ∑REE in Ioesses of different ages in the Luochuan section shows a narrow range of variation, indicating the homogeneity of materials in chemical composition. The REE in loess are concentrated mainly in silt.sized detrital minerals. Loesses of different ages and paleosols all are relatively enriched in rare-earth elements of the Ce family, and show similar REE distribution patterns. The fractinnatlon among various REEs in the loess is different from that in morainic, marine and lacustrine sediments,but is similar to that in sand samples from deserts in Northwest China. The ratios of Ce/Ce^* and Eu/Eu^* reflect that the provenance of loessic materials and their accumulating area are all in an oxidation environment with weakly basic mediums under arid or sub-arid climate.