Diagenesis and reservoir quality of the Lower and Middle Buntsandstein (Lower Triassic), SW Germany INAUGURAL - DISSERTATION zur Erlangung der Doktorwürde der Naturwissenschaftlich-Mathematischen Gesamtfakultät der Ruprecht-Karls-Universität Heidelberg vorgelegt von Dominik Soyk Heidelberg, 2015 Diagenesis and reservoir quality of the Lower and Middle Buntsandstein (Lower Triassic), SW Germany INAUGURAL - DISSERTATION zur Erlangung der Doktorwürde der Naturwissenschaftlich-Mathematischen Gesamtfakultät der Ruprecht-Karls-Universität Heidelberg vorgelegt von Dipl.-Geol. Dominik Soyk aus Schwetzingen, Deutschland Heidelberg, 2015 Gutachter: Prof. Dr. Thilo Bechstädt Prof. Dr. Harald Stollhofen Tag der mündlichen Prüfung 08. Juni 2015 Table of Contents Abstract ............................................................................................... I Kurzfassung ....................................................................................... II List of Abbreviations .......................................................................... V 1 Introduction ................................................................................... 1 1.1 Objectives ................................................................................................. 2 1.2 Study area ................................................................................................ 3 1.3 Geological Setting .................................................................................... 3 1.4 Stratigraphy .............................................................................................. 7 2 Methods ......................................................................................... 9 2.1 Sampling ................................................................................................... 9 2.2 Optical Microscopy ................................................................................. 10 2.3 Cathodoluminescence Microscopy ..........................................................11 2.4 Scanning Electron Microscopy ................................................................11 2.5 X-Ray Diffraction Analysis .......................................................................11 2.6 X-Ray Fluorescence Analysis ................................................................. 12 2.7 Whole Rock Geochemistry ..................................................................... 12 2.8 Fluid Inclusion Microthermometry ........................................................... 12 3 Results ......................................................................................... 14 3.1 Lithology and Lithofacies ........................................................................ 14 3.2 Detrital Mineralogy ................................................................................. 18 3.3 Authigenic Mineralogy ............................................................................ 20 3.3.1 Fe-Oxide and Fe-Hydroxide ........................................................ 20 3.3.2 Clay Minerals ............................................................................... 21 3.3.2.1 Illite and Smectite .......................................................... 22 3.3.2.2 Kaolinite ........................................................................ 28 3.3.2.3 Chlorite .......................................................................... 29 3.3.3 Quartz and amorphous silica ....................................................... 29 3.3.4 Feldspar ...................................................................................... 34 3.3.5 Carbonates .................................................................................. 36 3.3.6 Barite ........................................................................................... 36 3.3.7 Accessory Minerals ..................................................................... 36 3.4 Porosity and Compaction ....................................................................... 42 3.5 Fractures and Fracture Mineralization .................................................... 47 3.6 Fluid Inclusions ....................................................................................... 48 4 Discussion ................................................................................... 52 4.1 Lithology, Lithofacies and Depositional Environment ............................. 52 4.2 Detrital Mineralogy .................................................................................. 54 4.2.1 Quartz .......................................................................................... 54 4.2.2 K-Feldspar ................................................................................... 54 4.2.3 Plagioclase .................................................................................. 55 4.3 Provenance ............................................................................................ 58 4.4 Postdepositional Processes ................................................................... 60 4.4.1 Fe-Oxide and Fe-Hydroxide ........................................................ 61 4.4.2 Clay Minerals ............................................................................... 62 4.4.2.1 Kaolinite ........................................................................ 62 4.4.2.2 Illite and Smectite ......................................................... 63 4.4.3 Quartz .......................................................................................... 70 4.4.4 Feldspar ...................................................................................... 75 4.4.5 Carbonates .................................................................................. 76 4.4.6 Fracture Mineralization ............................................................... 77 4.4.7 Accessory Minerals ..................................................................... 78 4.4.8 Bleaching .................................................................................... 78 4.5 Diagenetic Sequence ............................................................................ 80 4.6 Burial and Thermal History ..................................................................... 83 4.7 Regional Diagenesis ............................................................................... 85 4.8 Reservoir quality ..................................................................................... 90 5 Conclusions ................................................................................ 93 6 References................................................................................... 98 Appendix 1 Lithofacies Types after Miall (1977) ................................................113 Appendix 2 Quartz Types after Bernet and Bassett (2005) ...............................117 Appendix 3 Point Counting Raw Data............................................................... 121 Appendix 4 Thin Section Petrography .............................................................. 133 Appendix 5 Whole Rock Geochemistry Results ............................................... 141 Appendix 6 Fluid Inclusion Thermometry Results ............................................. 151 Appendix 7 X-Ray Fluorescence Results ......................................................... 155 Appendix 8 X-Ray Diffractograms ..................................................................... 159 Chart 1 XRD Clay Mineral Fraction - Cleebourg ...................................... 161 Chart 2 XRD Clay Mineral Fraction - Well B 1 .......................................... 163 Chart 3 XRD Clay Mineral Fraction - Well B 2 .......................................... 163 Chart 4 XRD Clay Mineral Fraction - Ettlingen ......................................... 164 Chart 5 XRD Clay Mineral Fraction - Heidelberg, Molkenkur ................... 165 Chart 6 XRD Clay Mineral Fraction - Heidelberg, Im Kammerforst .......... 166 Chart 7 XRD Clay Mineral Fraction - Well A 2 .......................................... 167 Chart 8 XRD Clay Mineral Fraction - Leistadt .......................................... 168 Chart 9 XRD Whole Rock - Mosbach ....................................................... 170 Chart 10 XRD Clay Mineral Fraction - Neckargemünd............................... 172 Chart 11 XRD Whole Rock - Pirmasens..................................................... 173 Chart 12 XRD Clay Mineral Fraction - Rockenau ....................................... 175 Appendix 9 Sample Locations and Sample Codes ........................................... 177 Danksagung .................................................................................... 181 Abstract Tis research work deals with the diagenesis and reservoir quality of the Lower Triassic Buntsandstein in south-western Germany. The Buntsandstein in the study and aeolian sediments. The most promising reservoir units are the Lower and area is a continental succession with mostly fluvial and subordinately lacustrine Middle Buntsandstein, consisting mostly of stacked fluvial channel sandstones, Theinterlayered mineralogy by onlyof the thin Buntsandstein mudstone beds. indicates The Upper intense Buntsandstein weathering. Plagioclaseis shalying upward and is thus less favourable as reservoir. plagioclaseis completely were absent, apparently because lost it due was to compaction.already partly K-feldspar dissolved dissolution in the hinterland occurred afterand finally framework-supporting replaced by kaolinite quartz