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476 International Journal of Earth Sciences (2021) 110:467–485 13 (Bhatia and Crook 1986), since some of these elements are directly associated with felsic (Th y La) or mafic (Sc and Cr) sources. Th/Nb values for Montemolín and Tentudía forma- tions (avg. 0.85 and 0.95, respectively; Tables 1 and 2) are slightly higher to those of PAAS (0.77), whereas the Th/ Sc ratio obtained for the Montemolín Formation (0.62) is lower than Tentudía Formation and PAAS (0.76 and 0.91, respectively). A relative enrichment in Sc in the Montemolín Formation is in agreement with its CaO values. The aver- age values in Montemolín and Tentudía formations for the La/Th (4.29, and 3.48, respectively) and Zr/Sc (15.15 and 18.29, respectively) ratios are higher than the estimated for the UCC and the PAAS (2.7 and 13.13, respectively). These values point to a mixed source, dominated by an intermediate-felsic component (Cullers 2002). This interpre- tation is also suggested by the low values observed in both formations in the Ti/Zr ratio (23.21 and 20.71, respectively); and low contents of Cr (avg. 88 and 85, respectively), and Ni (avg. 42 and 39, respectively). A set of major and trace elements analyses (following Thompson 1982) was normalized to PAAS and plotted into a multivariate diagram for both Ediacaran metasedi- mentary series (Fig. 4d). Both formations display very similar patterns. They show depletion in the LILE ele- ments, with larger variability in the metagreywackes from the Tentudía Formation, especially in K and Sr, probably due to some post-depositional alteration. Instead, the metagreywackes from Montemolín Formation show a Fig. 4 Chemical diagrams for Montemolín and Ten- tudía formations. a Chemical classification diagram based on major elements (Herron 1988). b Maturity and chemi- cal weathering diagram based on major element distribution (after Linnemann and Romer 2002). c Chondrite normalized REE plot (Nakamura 1974); red line corresponds to the PAAS (Post Archean Australian Shale; Taylor and McLennan 1985). d PAAS normalized trace ele- ments diagram &KDSWHU