Tectonothermal evolution of the Sarandí del Yí Shear Zone and adjacent blocks (Uruguay): Implications for the assembly of Western Gondwana Dissertation zur Erlangung des mathemathisch-naturwissenschaftlichen Doktorgrades „Doctor rerum naturalium“ der Georg-August-Universität Göttingen im Promotionsprogramm Geowissenschaften der Georg-August University School of Science (GAUSS) vorgelegt von Sebastián Oriolo aus Buenos Aires Göttingen 2016 Betreuungsausschuss Prof. Dr. Siegfried Siegesmund Abteilung Strukturgeologie und Geodynamik Geowissenschaftliches Zentrum der Georg-August-Universität Göttingen Prof. Dr. Pedro Oyhantçabal Departamento de Geología Facultad de Ciencias, Universidad de la República Mitglieder der Prüfungskommission Referent Prof. Dr. Siegfried Siegesmund Abteilung Strukturgeologie und Geodynamik Geowissenschaftliches Zentrum der Georg-August-Universität Göttingen Korreferent Prof. Dr. Pedro Oyhantçabal Departamento de Geología Facultad de Ciencias, Universidad de la República Weitere Mitglieder der Prüfungskommission Prof. Dr. Jonas Kley Abteilung Strukturgeologie und Geodynamik Geowissenschaftliches Zentrum der Georg-August-Universität Göttingen Prof. Dr. Bernd Lammerer Fakultät für Geowissenschaften Ludwig-Maximilians-Universität München Dr. Klaus Wemmer Abteilung Isotopengeologie Geowissenschaftliches Zentrum der Georg-August-Universität Göttingen Dr. Florian Heidelbach Bayerisches Geoinstitut Universität Bayreuth Tag der mündlichen Prüfung: 14.07.2016 II Map it, my boy, and it will all come out Charles Lapworth Rocks do not suffer deformation; they enjoy it Robert Knipe III -Acknowledgements- In the first place, I would like to thank the committee for the discussion and observations, which helped to improve this work and stimulated future contributions. Many thanks to Siegfried Siegesmund and Pedro Oyhantçabal for giving me the chance to come to Germany and for accepting to supervise my PhD. Thanks for the guidance, patience, knowledge generosity and all advices about geology, science and life. I am especially indebted for the good times in the field and the shared asados/Grills and wines, also together with Klaus Wemmer. Special thanks go to Klaus Wemmer for his invaluable help in the laboratory and the field, especially concerning K-Ar data measurement and interpretation, and also for his critical suggestions and discussions regarding isotope geology. I am greatly indebted to the Iglesias family and Enrique Domínguez for the hospitality and logistic support in the field. The Department of Geology of the Universidad de la República (Uruguay) and the DINAMIGE are acknowledged for the support during two research stays in Montevideo and for granting access to the geological database of Uruguay, respectively. I would also like to thank Jorge Spoturno and Pablo Lara for discussions regarding the geology of Uruguay. Florian Heidelbach is greatly acknowledged for the help with quartz CPO measurements and data interpretation. Many thanks to him, his family and the Bayerisches Geoinstitut for the hospitality during a short research stay in Bayreuth. I would like to thank Miguel Basei for the guidance during U-Pb and Lu-Hf data processing and interpretation. I would also like to acknowledge him for several discussions concerning the Precambrian geology of South America and the evolution of Gondwana. Jeff Benowitz, Jörg Pfänder, Felix Hannich and Blanka Sperner are acknowledged for Ar/Ar measurements and the help with data processing and interpretation, whereas Dirk Frei is thanked for U-Pb measurements of detrital zircons. Harald Tonn and Daniel Picchi are thanked for the help IV with thin section preparation and Kerstin Techmer, for REM assistance. Brigitte Dietrich, Franziska Wilsky, Klaus Simon and Nicole Nolte are acknowledged for the support and advices during preparation, measurement and interpretation of the Rb-Sr samples. All members of the Department of Structural Geology and Geodynamics are acknowledged for discussions and critical observations related to this work. Thanks to Craig Robertson for the interesting discussion about the origin of the term “Gondwana”. To Graciela Sosa and Alfons van den Kerkhof go special thanks for the hospitality and the shared meals at their home. I would also like to acknowledge Graciela for the pastafrola, dulce de membrillo and, especially, for the shared mates every morning. Filiz Afşar, Jan-Peter Duda, Mathias Hueck, Elco Luijendijk, Silke Meier and Victoria Shushakova are thanked for the (many) shared beers, coffees and talks. Special thanks to Filiz and Jan for their “always-open-house” and their continuous help and support. Thanks to Filiz for the help with the abstract translation and for tolerating our never-ending discussions about science and geology with Jan. I would also like to acknowledge the D’Almeida-Cattaneo family, Hilario Espinosa and Santiago Finamore for the many asados, pizzas, beers and wines shared together. I am deeply indebted to Silvia Japas for showing me the amazing world of rock deformation and for guiding me during my entire academic career since the very early beginning. I thank her for her selfless continuous support and help. Last but not least, I would like to thank Ivana, my parents and my family for their continuous support. Also to my friends in Argentina, who accompanied me even in the distance. I am also indebted to DAAD (Deutscher Akademischer Austausch Dienst) for a long-term PhD scholarship (A/12/75051), which made this work possible. DAAD is also acknowledged for financial support to print this thesis. V -PREFACE- New data presented in this work are divided into different contributions, which are outlined below. These results as a whole comprise an integral approach to constrain the evolution of the study area. Chapter 1 and 2 are introductory, whereas results obtained in this thesis are included in Chapters 3 to 7. Chapter 8, in turn, presents a critical discussion of all new and available data, and Chapter 9 outlines the main conclusions of the work. Chapter 1 presents the aim of the work as well as an overview of Gondwana evolution and regional geology of the study area. Chapter 2 reviews methodologies applied in this work, including all methods and analytical procedures. Chapter 3 (Oriolo et al., 2016, Precambrian Research) presents new U-Pb and Hf zircon data from the basement of the study area, which comprise the Nico Pérez and Piedra Alta terranes. These results are integrated with available data from these blocks as well as from adjacent units in order to establish regional correlations and the allochthony/autochthony of the Nico Pérez Terrane regarding the Río de la Plata Craton. Chapter 4 (Oyhantçabal et al., submitted to Precambrian Research) includes U-Pb and Hf detrital zircon data from the metasedimentary cover of the Dom Feliciano Belt, which overlains the basement units studied in Chapter 3. Age, provenance and tectonic setting of these units are thus discussed. In the corresponding manuscript, these results are integrated with geochemical and Sm-Nd whole-rock data from the same units, which were mostly analysed by the first author. Chapter 5 (Oriolo et al., 2015, International Journal of Earth Sciences) presents kinematic, structural and microstructural data from the Sarandí del Yí Shear Zone and adjacent blocks. Quartz CPO data and strain analysis of the mylonites of the shear zone are integrated with these data in order to constrain the structural evolution of the Sarandí del Yí Shear Zone. VI Chapter 6 (Oriolo et al., 2016, Tectonics) complements data from Chapter 5, as it incorporates geochronological data from the Sarandí del Yí Shear Zone. Hence, integration of structural, microstructural and geochronological data allows assessing the timing of deformation of the shear zone. Additionally, implications for dating the age of deformation in mylonitic rocks are discussed as well. Chapter 7 (Oriolo et al., submitted to Journal of Structural Geology) presents structural, microstructural and geochronological data from the Dom Feliciano Belt. The timing of deformation and metamorphism and structural evolution of the belt are thus constrained. Chapter 8 integrates all available data and results obtained in this work into an evolutionary model for the study area. As a corollary, the history of Western Gondwana assembly is reassessed, evaluating the role of major crustal blocks and Neoproterozoic orogenic belts (Oriolo et al., submitted to Geoscience Frontiers). Chapter 9 summarizes the main results of the work. The following manuscripts are part of this doctoral thesis: Oriolo, S., Oyhantçabal, P., Heidelbach, F., Wemmer, K., Siegesmund, S. 2015. Structural evolution of the Sarandí del Yí Shear Zone: kinematics, deformation conditions and tectonic significance. International journal of Earth Sciences 104, 1759-1777. Oriolo, S., Oyhantçabal, P., Wemmer, K., Basei, M.A.S., Benowitz, J., Pfänder, J., Hannich, F., Siegesmund, S. 2016. Timing of deformation in the Sarandí del Yí Shear Zone, Uruguay: implications for the amalgamation of Western Gondwana during the Neoproterozoic Brasiliano– Pan-African Orogeny. Tectonics 35, 754-771. Oriolo, S., Oyhantçabal, P., Basei, M.A.S., Wemmer, K., Siegesmund, S. 2016. The Nico Pérez Terrane (Uruguay): from Archean crustal growth and connections with the Congo Craton to late Neoproterozoic accretion to the Río de la Plata Craton. Precambrian Research 280, 147-160. VII Oyhantçabal, P., Oriolo, S., Basei, M.A.S., Frei, D., Marahrens, J., Wemmer, K., Siegesmund, S. Provenance