The Variscan Belt of Western Europe, Volume 2

Preface ix Yoann DENÈLE and Julien BERGER Introduction xi Yoann DENÈLE and Julien BERGER List of Figures xxiii Chapter 1 High-Temperature Metamorphism and Syn- to Late-Orogenic Magmatism 1 Arnaud VILLAROS, Oscar LAURENT, Simon COUZINIE and Jean-François MOYEN 1.1 Introduction 1 1.2 High-temperature/low- to medium-pressure metamorphism and partial melting of the Variscan crust 5 1.2.1 Evolution of high-temperature metamorphism 5 1.2.2 Petrology of high-temperature metamorphism 7 1.3 Late-orogenic magmatism 13 1.3.1 Two mica peraluminous leucogranites (MPG) 13 1.3.2 Biotite and cordierite peraluminous granites (CPG) 14 1.3.3 K-rich calc-alkaline granitoids (KCG) – durbachites, vaugnerites 16 1.3.4 Synchronous orogenic volcanism of HT metamorphism 17 1.3.5 Overview 18 1.4 Causes and geodynamic implications of crustal melting 19 1.4.1 Synchronous crustal melting episode of the Variscan collision 19 1.4.2 Melting associated with orogenic extension 19 1.4.3 High-temperature melting and the formation of domes 20 1.4.4 Synthesis of HT metamorphic evolution 22 1.4.5 Outlook 23 1.5 References 24 Chapter 2 Late-Orogenic Structural Reorganization of the Variscan Belt during the Upper Carboniferous 35 Yoann DENÈLE and Bryan COCHELIN 2.1 Introduction 35 2.2 Major structures of the Variscan belt of Western Europe 38 2.3 Ibero-Armorican Arc 43 2.3.1 Formation of a major orocline in the upper Carboniferous 43 2.3.2 Structure and evolution of the Armorican domain 46 2.3.3 The Armorican shear zones 49 2.3.4 A simple shear model in a horizontal plane at the scale of the Central Armorican domain 53 2.4 Late orogenic deformation in the internal domain 56 2.4.1 South Armorican domain: thinning and longitudinal stretching of a previously thickened domain 56 2.4.2 The Carboniferous syn-tectonic plutons of the French Massif Central: interaction between strike–slip shear zone and longitudinal extension 65 2.4.3 The Velay dome and the Pilat detachment: transverse extension in the hinterland 74 2.5 Late-orogenic deformation in the southern foreland domain 77 2.5.1 The Montagne Noire migmatite-cored gneiss dome 77 2.5.2 The Variscan segment of the Pyrenees 85 2.6 Summary and discussion on the restructuring of the Variscan belt in the Carboniferous 93 2.7 Conclusion 99 2.8 References 99 Chapter 3 Sedimentary Basins and Evolution of Reliefs Associated with the Variscan Cycle in France and Adjacent Countries 121 Markus ARETZ, Élise NARDIN, Frédéric CHRISTOPHOUL, Julien DENAYER 3.1 Introduction 121 3.2 Foreland basins along the Southern Laurussian Margin 122 3.2.1 The Ardenne and the Boulonnais 123 3.2.2 Rhenish Massif 138 3.3 Basins in the Inner Variscan zone 146 3.3.1 Armorican Massif Basins 147 3.3.2 Northern Vosges 152 3.4 Regions of the Gondwanan Margin and Foreland Basin 152 3.4.1 Middle Vosges and Southern Vosges 153 3.4.2 Morvan 154 3.4.3 Montagne Noire: reference for the Peri-Gondwanan Foreland Basin 154 3.4.4 The Pyrenees 162 3.5 Post-orogenic stage: Stephanian-Permian basins 169 3.5.1 Stratigraphy 171 3.5.2 Geodynamic and structural context 172 3.5.3 General sedimentological trends in Stephanian-Permian basins 177 3.6 Conclusion 179 3.7 References 181 Conclusion 203 Yoann DENÈLE and Julien BERGER List of Authors 215 Index 217 Summary of Volume 1 219