The Tapes Complex (Nico Pérez Terrane, Uruguay): Constraining the Mesoproterozoic evolution of the Río de la Plata Craton

The Tapes Complex crops out in the southeastern Nico Pérez Terrane (NPT) of the Río de la Plata Craton and forms part of a NE-trending Mesoproterozoic belt together with the Calymmian (1.48–1.43 Ga) Parque UTE and Mina Verdún groups. The complex is characterized by interbedded/tectonically interleaved metasedimentary (mainly siliciclastic) and metaultramafic rocks, with subordinate intercalations of metabasites, carbonate and chert, all metamorphosed in the greenschist facies. The age of the Tapes Complex is constrained by: (i) a U–Pb SIMS age of 1360 ± 12 Ma for the youngest detrital zircon, (ii) the K–Ar age of 1253 ± 32 Ma for synkinematic muscovite of the Zapicán thrust, which affects the unit, and (iii) an Sm–Nd isochronic age of 1403 ± 150 Ma for ultramafic and mafic rocks. The intruding Tapes Chico Syenite yielded a much younger U–Pb SIMS age of 601 ± 5 Ma, associated with Brasiliano-Pan African tectonism, negative εHf values (mean = −31), δ18O zircon ratios ranging between 5.45 and 6.68‰ V-SMOW and inherited zircons dated at 1774-1756 Ma. The best preserved mafic and ultramafic samples yielded Nd model ages (TDM) between 1.55 and 1.68 Ga, close to the assumed crystallization age, and positive εNd(t). Nd model ages of metasedimentary rocks vary between 1.8 and 3.1 Ga, which is interpreted as reflecting two contrasting sources: Archean units of the NPT and Mesoproterozoic mafic and ultramafic rocks, including fragments of oceanic crust. Chondrite-normalized REE patterns of metasedimentary rocks are characterized by LREE enrichment and lack of an Eu anomaly, similar to REE patterns of co-occurring metabasalts. High MgO concentrations, high Cr/V and low Y/Ni and Th/Sc ratios imply the involvement of ultramafic rocks in the source area, which is also supported by whole-rock Pb isotope data. A geodynamic evolution is envisaged, from an extensional tectonic setting between 1.48–1.43 Ga (rift or retroarc basin) into a compressional, retroarc foreland basin at ca. 1.25–1.20 Ga, the latter being probably related to the Kibaran Orogeny in the Namaqua-Natal Belt. It is proposed that the corresponding arc granites and high-grade metamorphic rocks are likely to be found in one of the several terranes in the Namaqua sector of the belt. The Apiaí Terrane (Ribeira Belt, Brazil) shows a similar geological record and evolution as the NPT, and maybe a fragment of the latter displaced to the NW by the Ibaré Shear Zone. The Tapes Complex is a key unit for understanding the assembly of the Río de la Plata and Kalahari cratons, and their incorporation into the Rodinia supercontinent.Fil: Gaucher, Claudio. Universidad de la República; UruguayFil: Frei, Robert. Universidad de Copenhagen; DinamarcaFil: Samaniego, Lucía. Centro Regional para la Gestión de Aguas Subterráneas; Uruguay. Universidad de la República; UruguayFil: Will, Thomas M.. Universität Würzburg; AlemaniaFil: Chemale, Farid. Universidad de Vale do Rio dos Sinos; BrasilFil: Gargiulo, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; ArgentinaFil: Poire, Daniel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; ArgentinaFil: Ling, Xiaoxiao. Chinese Academy of Sciences. Institute of Geology and Geophysics. State Key Laboratory of Lithospheric Evolution; ChinaFil: Li, Xian Hua. Chinese Academy of Sciences. Institute of Geology and Geophysics. State Key Laboratory of Lithospheric Evolution; ChinaFil: Li, Qiu Li. Universidad de Copenhagen; Dinamarc

Early Holocene ritual complexity in South America: the archaeological record of Lapa do Santo (east-central Brazil)

Early Archaic human skeletal remains found in a burial context in Lapa do Santo in eastcentral Brazil provide a rare glimpse into the lives of hunter-gatherer communities in South America, including their rituals for dealing with the dead. These included the reduction of the body by means of mutilation, defleshing, tooth removal, exposure to fire and possibly cannibalism, followed by the secondary burial of the remains according to strict rules. In a later period, pits were filled with disarticulated bones of a single individual without signs of body manipulation, demonstrating that the region was inhabited by dynamic groups in constant transformation over a period of centuries

Caracterização das variantes gênicas que codificam para o antígeno B de Echinococcus granulosus

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Clonagem e expressão de vioA, Fis e serino-protease de Chromobacterium violaceum

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U-Pb age constraints for the La Tuna Granite and Montevideo Formation (Paleoproterozoic, Uruguay): Unravelling the structure of the Río de la Plata Craton

The Río de la Plata Craton is a continental block that crops out in Uruguay, eastern Argentina, southernmost Brazil and Paraguay. It comprises in Uruguay the Piedra Alta, Tandilia and Nico Pérez terranes, separated by the Colonia and the Sarandí del Yí megashears. The La Tuna Granite, which intrudes the Araminda metasandstones in the Tandilia Terrane, was considered Cambrian in age and the intruded sandstones were assigned to the Neoproterozoic Piedras de Afilar Formation. We show that the granite is Paleoproterozoic in age and that the host metasandstones do not belong to the Piedras de Afilar Formation, but to the Paleoproterozoic Montevideo Formation. U-Pb LA ICP-MS of zircon ages for the La Tuna Granite yielded a concordant crystallization age of 2156 ± 26 Ma. Furthermore a metamorphic event at 2010 ± 9 Ma is revealed by Pb stepwise leaching dating of monazites. U-Pb detrital zircon ages of the host Araminda metasandstone yield an upper intercept discordia age of 2152 ± 29 Ma, which marks the intrusion of the La Tuna pluton, and which is in accordance with the zircon U-Pb LA ICP MS constraints. A concordant U-Pb detrital zircon age of 2465 ± 40 Ma provides a maximum depositional age constraint for the metapsammites. Comparing quartz arenites of the Ediacaran Piedras de Afilar Formation with the Araminda metaquartzites, we conclude that they are very similar regarding petrology but they differ in age and metamorphic overprint. Detrital zircons in quartz arenites of the Piedras de Afilar Formation show youngest ages of 1.0 Ga. On the other hand, detrital zircons recovered from the Araminda metasandstones and the age of the intruding granite allow interpreting a depositional age between 2465 and 2150 Ma. Nd model ages show crustal residence times in average more than 200 myr older for the Tandilia Terrane both in Uruguay and Argentina, with a significant Neoarchean component, which is lacking in the Piedra Alta Terrane. Whereas the Piedra Alta Terrane was formed rapidly from a juvenile source, the Tandilia Terrane shows a more protracted history. Our data support the interpretation of the Tandilia Terrane as a separate tectonostratigraphic unit.Fil: Pamoukaghlián, Karina. Universidad de la República. Facultad de Ciencias; UruguayFil: Gaucher, Claudio. Universidad de la República. Facultad de Ciencias; UruguayFil: Frei, Robert. Universidad de Copenhagen; DinamarcaFil: Poire, Daniel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; ArgentinaFil: Chemale, Farid. Universidade do Brasília; BrasilFil: Frei, Dirk. Geological Survey of Denmark and Greenland; DinamarcaFil: Will, Thomas M.. Universität Würzburg; Alemani