The Cerro Olivo Complex: a pre-collisional Neoproterozoic magmatic arc in Eastern Uruguay

The Cerro Olivo Complex is one of the few occurrences of the basement rocks in the Dom Feliciano Belt. It contains migmatitic paragneisses and orthogneisses that host granites of ca. 600–540 Ma Aigua Batholith. The main orthogneisses are rich in orthopyroxene + Ca-plagioclase (Cerro Bori unit), but K-feldspar augen gneisses are also common (Centinela-Punta del Este unit). The paragneisses (Chafalote unit) are semi-pelitic migmatites that contain restites of metapelites, quartzites, amphibolites, and calc-silicate rocks. A clockwise pressure–temperature–time (P–T-t) path and two deformational events affected the Cerro Olivo Complex rocks. Granulitic high-pressure (HP)–high-temperature (HT) peak conditions were followed by low pressure (LP)–HT decompression. The first deformation (K1) developed an E–W gneissic foliation and westward-stretching lineations, whereas the second (K2) produced NS to NE–SW low-temperature mylonitic foliation and southward-stretching lineations. New SHRIMP U–Pb data from zircon cor...