University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School 11-19-2014 Mantle-crust Interaction in Granite Petrogenesis in Post-collisional Settings: Insights from the Danubian Variscan Plutons of the Romanian Southern Carpathians Ciprian Cosmin Stremtan University of South Florida, [email protected] Follow this and additional works at: https://scholarcommons.usf.edu/etd Part of the Geochemistry Commons, and the Geology Commons Scholar Commons Citation Stremtan, Ciprian Cosmin, "Mantle-crust Interaction in Granite Petrogenesis in Post-collisional Settings: Insights from the Danubian Variscan Plutons of the Romanian Southern Carpathians" (2014). Graduate Theses and Dissertations. https://scholarcommons.usf.edu/etd/5624 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Mantle-crust Interaction in Granite Petrogenesis in Post-collisional Settings: Insights from the Danubian Variscan Plutons of the Romanian Southern Carpathians by Ciprian Cosmin Stremțan A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy School of Geosciences College of Arts and Sciences University of South Florida Co-Major Professor: Jeffrey G. Ryan, Ph.D. Co-Major Professor: Paul Wetmore, Ph.D. Jonathan G. Wynn, Ph.D. Ioan Balintoni, Ph.D. Date of Approval: November 19, 2014 Keywords: granitoid, continental crust, delamination, trace elements, isotopes Copyright © 2014, Ciprian Cosmin Stremțan DEDICATION To all the wonderful people who made this possible. TABLE OF CONTENTS List of Tables ................................................................................................................................. iv List of Figures ................................................................................................................................. v Abstract ........................................................................................................................................ viii Chapter One: Post-collisional Late Variscan Magmatism in the Danubian Domain (South Carpathians, Romania) Documented by Zircon U/Pb LA-ICP-MS .............................. 1 Note to Reader .................................................................................................................... 1 Abstract ............................................................................................................................... 1 Introduction ......................................................................................................................... 2 Variscan Orogeny: Plate Tectonics Concepts and Timing ................................................. 3 Geological Setting ............................................................................................................... 6 Alpine Structure of the South Carpathians ............................................................. 6 Pre-Variscan Structure of the South Carpathians ................................................... 7 Variscan Events in South Carpathians .................................................................... 8 Samples and Analytical Methods........................................................................................ 9 Samples ................................................................................................................... 9 Analytical Methods ............................................................................................... 11 Results ............................................................................................................................... 13 Discussion ......................................................................................................................... 17 General Plate Tectonics Concept .......................................................................... 17 Major Element Geochemistry ............................................................................... 18 Trace Elements and Isotopic Data ........................................................................ 20 Delamination Model ............................................................................................. 21 Conclusions ....................................................................................................................... 24 References ......................................................................................................................... 25 Chapter Two: Petrology and Geochemistry of the Late Variscan Post-collisional Furcătura Granitic Pluton South. Carpathian Mts. (Romania). ............................................................... 34 Abstract ............................................................................................................................. 34 Introduction ....................................................................................................................... 35 i Geological Setting ............................................................................................................. 37 Samples and Petrography .................................................................................................. 40 Analytical Methods ........................................................................................................... 43 Major and Trace Elements .................................................................................... 43 Oxygen Isotopes.................................................................................................... 44 Strontium and Neodymium Isotopes .................................................................... 45 Results ............................................................................................................................... 46 Whole-rock Geochemistry .................................................................................... 46 Isotope Geochemistry ........................................................................................... 54 Discussion ......................................................................................................................... 55 P-Tº Conditions of Granitoid Formation .............................................................. 55 Petrogenesis .......................................................................................................... 57 Timing of the Pluton Emplacement and Comparison with the Variscan Events from Central-Western Europe ......................................................................... 68 Geodynamic Implications ..................................................................................... 69 Conclusions ....................................................................................................................... 73 References ......................................................................................................................... 74 Chapter Three: Post Collisional Magmatism Associated with Variscan Orogeny in the Danubian Domain (Romanian Southern Carpathians): the Motru Dyke Swarm ................... 92 Abstract ............................................................................................................................. 92 Introduction ....................................................................................................................... 93 Geological setting ............................................................................................................. 95 Analytical Methods ........................................................................................................... 97 Major and Trace Elements .................................................................................... 97 Radiogenic Isotopes .............................................................................................. 98 Results ............................................................................................................................... 99 Samples and Petrology .......................................................................................... 99 Bulk-rock Geochemistry ..................................................................................... 100 Bulk-rock Sr-Nd Isotope Geochemistry ............................................................. 108 Discussion ....................................................................................................................... 109 Timing of the MDS Intrusion ............................................................................. 109 Petrogenesis ........................................................................................................ 112 Mode of MDS Formation.................................................................................... 119 Conclusions ..................................................................................................................... 120 ii References ....................................................................................................................... 121 Chapter Four: The Role of the Continental Crust and Lithospheric Mantle in Variscan Post- Collisioanl Magmatism – Insights from Muntele Mic, Ogradena, Cherbelezu, Sfârdinu, and Culmea Cernei Plutons (Romanian