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During the last two decades, the igneous-metamorphic Paleoproterozoic basement rocks of the Tandilia Belt were dated by U-Pb SHRIMP on zircon and titanite to constrain the elapsed time of orogenesis. The obtained period is between 2.26 and 2.06 Ga (see reviews by Ohyantçabal et al., 2018 and Santos et al., 2019), much more extended than for Phanerozoic orogens. Recently, U-Th-Pb monazite ages confirmed this period of crustal growth for the Tandilia Belt but also suggested younger thermotectonic events (Massonne et al., 2012; Martínez et al., 2017; Bianchi et al., 2020). It is highlighted that monazite, a common accessory mineral in Ca-poor crustal rocks such as peraluminous granites and pelitic schists (e.g. Parrish 1990; Piechocka et al., 2017), is widespread in high-grade partly molten metamorphic rocks and associated igneous rocks of the Tandilia Belt. In order to obtain more information on the evolution of this orogenic area, we integrated published and new data of in situ analyzed monazite, acquired with a CAMECA SX100 electron microprobe of the Institut für Mineralogie und Kristallchemie, Universität Stuttgart (Germany), under the same routine conditions of 180 nA of current and 20 kV of acceleration voltage. A dataset of 251 suitable chemical analyses of monazite (SiO2 < 0.9 wt.% and total oxides > 96 wt.%) and their respective U-Th-Pb single ages were obtained, gathered in 10 different rock samples from five distant localities of the Tandilia Belt (Fig. 1). Compositional grain zoning observed on backscattered images and X-ray element maps revealed complex processes of crystallization, dissolution, and recrystallization. Monazite analyses were grouped based on chemistry and age. The dataset of ages including 1σ analytical uncertainties was processed with the software IsoplotR by Vermeesch (2018). Y2O3) and high-U (0.4 - 0.6 wt.% UO2) of the garnet-bearing biotite gneiss of El Morro hill, yielded an age of 2065 ± 3.5 Ma. Group II, including low-Y (< 0.5 wt.% Y3O2) and intermediate-Th (4 - 6 wt.% ThO2) monazite of the peraluminous leucogranite of La Virgen hill, gave a mean age of 2089 ± 3 Ma attributed to post-orogenic magmatism and the anatexis of country rocks of the ?Camboriu? orogeny (Angeletti et al., 2021). Group I, yielding an age of 2127 ± 10 Ma, corresponds to monazite with low-Th (2 ? 4.5 wt.% ThO2) and high-Y (see above) of the partly molten quartz-sillimanite nodule-bearing gneiss of La Plata hill and to monazite of the leucogranite of La Virgen hill with variable high Y contents (0.8 ? 2.2 wt.% Y3O2). The latter age group might correspond to inherited monazite from the subduction-related initial accretionary stage of the ?Encantadas? orogeny (Angeletti et al., 2021). Besides these five groups, ages older than 2250 Ma were determined in rocks of the southeastern Tandilia Belt (Cinco Cerros and San Verán hills, Fig. 1). Younger ages in the range of 1950 ? 1800 Ma were determined on monazite in migmatites from San Verán and El Morro hills (Fig. 1). Monazite with these ages have intermediate values of La2O3 (13 - 15 wt.%), Y2O3 (1 - 2 wt.% ), and ThO2, (3 - 5 wt.%) and could be assigned to deformation during final exhumation and slow cooling of the orogen (Massonne et al., 2012; Bianchi et al., 2020). As a result, the presented dataset of monazite ages points to intermittent high-grade metamorphic and associated magmatic events after the zircon constrained ?Camboriu? orogeny between 2.10 and 2.08 Ga (Hartmann et al., 2002; Cingolani et al., 2002) and, thus, compatible with an even longer-lasting Trans-Amazonian (Almeida et al., 1973) or Transplatense (Santos et al., 2019) orogenic cycle.