Coupling between Climate and Tectonics? Low temperature thermochronology and structural geology applied to the pro‐wedge of the European Alps Dissertation zur Erlangung des Doktorgrades im Fachbereich Geowissenschaften an der Freien Universität Berlin Christoph von Hagke Berlin, 2012 1. Gutachter: Prof. Dr. Onno Oncken Freie Universität Berlin Helmholtz‐Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ 2. Gutachter: Prof. Dr. Mark Handy Freie Universität Berlin Tag der Disputation: 27.06.2012 Erklärung Hiermit versichere ich, dass die vorliegende Dissertation ohne unzulässige Hilfe Dritter und ohne Benutzung anderer als der angegebenen Literatur angefertigt wurde. Die Stellen der Arbeit, die anderen Werken wörtlich oder inhaltlich entnommen sind, wurden durch entsprechende Angaben der Quellen kenntlich gemacht. Diese Arbeit hat in gleicher oder ähnlicher Form noch keiner Prüfungsbehörde vorgelegen. Berlin, Mai 2012 HARNISCHSTRIEMEN, Faltenachsen, Durchstich‐ punkte: dein Gelände. An beiden Polen der Kluftrose, lesbar: dein geächtetes Wort. Nordwahr. Südhell. SLICKENSIDES, fold‐axes, rechanneling‐ points: your terrain. On both poles of the cleftrose, legible: your outlawed word. Northtrue. Sunbright. Paul Celan 1967 (Atemwende), translated by Pierre Joris (Breathturn) Table of content Coupling between Climate and Tectonics? ................................................................................ 1 Low temperature thermochronology and structural geology applied to the pro‐wedge of the European Alps ............................................................................................................................ 1 1 Thermochronological approach to the late stage evolution of the Molasse basin and the Interaction between climate and tectonics ............................................................................... 9 1.1 General Introduction and Summary ............................................................................ 9 1.2 Allgemeine Einführung und Zusammenfassung ........................................................ 12 1.3 The Molasse Basin ..................................................................................................... 15 1.3.1 Geographic setting ............................................................................................. 15 1.3.2 Pre‐Tertiary Basin Evolution ............................................................................... 15 1.3.3 Tertiary Basin Evolution ..................................................................................... 17 1.3.4 Tectonic Setting .................................................................................................. 22 1.4 Methods ..................................................................................................................... 23 1.4.1 Principles of Thermochronology ........................................................................ 23 The concept of closure temperature ................................................................................... 23 1.4.2 Fission track formation and fading ..................................................................... 26 1.4.3 Fission track age determination ......................................................................... 29 1.4.4 (U‐Th‐Sm)/He dating .......................................................................................... 31 2 Resolving the latest uplift and erosion history of the Northern Alpine Foreland Basin with low temperature thermochronology ............................................................................... 35 2.1 Introduction ............................................................................................................... 35 2.2 Regional geologic context .......................................................................................... 37 Tertiary basin evolution ....................................................................................................... 38 2.3 The Subalpine Molasse .............................................................................................. 39 General overview of the discussed cross sections ............................................................... 41 2.4 Fission Track and (U‐Th‐Sm)/He Principles and Methods ......................................... 42 2.5 Sampling Strategy ...................................................................................................... 43 2.6 Thermal Modelling of the data .................................................................................. 45 2.7 Results ........................................................................................................................ 46 2.7.1 AFT age distribution ........................................................................................... 46 Entlebuch horizontal section ................................................................................................ 46 Entlebuch vertical section .................................................................................................... 55 Rigi horizontal section .......................................................................................................... 56 Rigi vertical section .............................................................................................................. 58 2.7.2 Comparison of EDM and LA‐ICP‐MS AFT results ................................................ 59 2.7.3 (U‐Th‐Sm)/He age distribution ........................................................................... 61 Entlebuch horizontal section ................................................................................................ 61 Entlebuch drill hole section .................................................................................................. 61 Rigi horizontal section .......................................................................................................... 62 Rigi vertical section .............................................................................................................. 63 2.7.4 Comparison of apatite (U‐Th‐Sm)/He and AFT results ...................................... 63 2.7.5 Modelled burial and exhumation histories ........................................................ 64 2.8 Discussion .................................................................................................................. 69 2.8.1 Thermochronology age pattern across thrusts .................................................. 70 2.8.2 Heat flow across active thrusts .......................................................................... 72 2.8.3 Tectonics in the Subalpine Molasse ................................................................... 72 2.8.4 The link to the inner Alps ................................................................................... 73 2.8.5 The link to the Jura Mountains and critical taper theory .................................. 75 2.9 Conclusions ................................................................................................................ 76 2.10 Acknowledgements ................................................................................................... 77 3 Supplementary information to “Resolving the latest uplift and erosion history of the Northern Alpine Foreland Basin with low temperature thermochronology” ......................... 78 3.1 Density and magnetic separation techniques applied .............................................. 78 3.2 Apatite fission track dating and its application ......................................................... 78 3.2.1 Theoretical background ..................................................................................... 78 3.2.2 Application of the fission track method ............................................................. 79 3.3 Assumption of Ns = 0.5 .............................................................................................. 89 3.4 EDM sampling strategy and age dating procedure ................................................... 90 3.5 Differences between LA‐ICP‐MS and EDM data ........................................................ 90 3.6 Apatite (U‐Th‐Sm)/He dating and its application ...................................................... 92 3.6.1 Theoretical background ..................................................................................... 92 3.6.2 Application of the (U‐Th‐Sm)/He method .......................................................... 94 3.7 Excluding single (U‐Th‐Sm)/He ages .......................................................................... 94 3.8 The weighted mean (U‐Th‐Sm)/He age ..................................................................... 95 3.9 Modelling the data .................................................................................................... 97 3.10 Heat and fluid flow in the NAFB ................................................................................ 97 3.11 Glacial erosion in the NAFB ....................................................................................... 99 3.12 Calculation of shortening based on thermochronology .......................................... 100 4 Critical taper analysis of the Central Alps reveals variations in detachment strength. 103 4.1 Introduction ............................................................................................................. 103 4.2 Geological framework ............................................................................................