Figure 3

REE patterns of XAa, XAu, local soil, UCC, ECA and PAAS. (a) Chondrite-normalized REE patterns. (b) Boxplot of REE ratios normalized to chondrite for XAa, XAu and soil. XAa: n = 20. XAu: n = 21. Soil: n = 9. C-sample element concentration of the samples, C-chondrite element concentration of chondrite, XAa—Xanthoria alfredii, XAu—X. ulophyllodes, ECA argillaceous rocks in the eastern part of China, PAAS post-Archean Australian shale, UCC upper continental crust, REE rare earth element, LREE light REE (La, Ce, Pr, Nd, Sm, and Eu), HREE heavy REE (Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu).