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132 are therefore lithologies with relatively homogeneous juvenile isotopic sources, since these values are similar to those calculated for the evolution of the depleted mantle at the age of the ophiolite protoliths (Figure 8a; DePaolo and Wasserburg 1976). Within the Mérida Massif, mafic rocks of similar ages to those of the ophio- lite protoliths are found at the base of the Montemolín Formation. These lithologies represent a succession of sills and intrusive stocks in the siliciclastic series dated at c . 600 Ma, the origin of which has been related to activity of the peri-Gondwanan magmatic arc from which the Upper Schist-Metagranitoid Unit was derived (Rojo- Pérez et al . 2022). The Nd model ages calculated for these metabasites range between 1316 and 2110 Ma and are similar to those obtained for the Nd isotopic sources of the siliciclastic rocks of the Serie Negra (Figure 8a; Rojo-Pérez et al . 2022). Hence, we considered the intrusive mafic rocks at the base of the Montemolín Formation to have been derived from partial melting of a mantle wedge strongly infiltrated by fluids generated Figure 5. a), b) Chondrite-normalized REE plots of the mafic and felsic rocks, respectively, from the Mérida Ophiolite (normalizing REE values after Nakamura 1974). c) Co-Th classification diagram (Hastie et al . 2007). Discrimination diagrams for the mafic rocks. d) MnO–P 2 O 5 –TiO 2 diagram (Mullen 1983). e) Th-Nb-Hf diagram (Wood 1980). 12 R. ARENAS ET AL. &KDSWHU