Tectono-Stratigraphic Evolution of Deep-Marine Clastic Systems in the Eocene Ainsa and Jaca Basins, Spanish Pyrenees: Petrographic and Geochemical Constraints
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Tectono-stratigraphic evolution of deep-marine clastic systems in the Eocene Ainsa and Jaca basins, Spanish Pyrenees: petrographic and geochemical constraints Kanchan DAS GUPTA Department of Earth Sciences University College London Thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy University of London October 2008 UMI Number: U592597 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. Dissertation Publishing UMI U592597 Published by ProQuest LLC 2013. Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 Abstract The Early-Middle Eocene deep-marine siliciclastic systems of the Ainsa and Jaca foreland basins, Spanish Pyrenees, have been used to develop and support generic models for deep-marine deposits, from process-based to system-based perspectives, and these ideas have been applied globally by academics and industry alike. Despite the considerable amount of research into many aspects of sedimentology of the Ainsa and Jaca basins, the widely-adopted stratigraphic correlation of sandstone systems in the Ainsa and Jaca basins is very poorly-constrained, although the stratigraphy and accurate correlation of sandstone bodies along the basin are paramount to any depositional models that arise from any studies in the Ainsa and Jaca basins. This study used petrography, geochronology, major and trace element geochemistry to better constrain and understand the evolution of the basinal sediments and fingerprint the sandstone bodies within the Ainsa - Jaca basin as a means of correlation. An additional pilot study was carried out on carbon and oxygen isotopic signatures of larger foraminifera from the outcrops. Three discrete sediment sources are recognised for the deep-marine Early to Mid-Eocene sandstone bodies in the Ainsa and Jaca basins. The arenite composition in the Ainsa and Jaca basins is interpreted to be mainly controlled by synsedimentary tectonic processes that led to changes in sediment sources during basin evolution. Comprehensive petrography data shows that each system of the Ainsa and Jaca basins has a characteristic petrofacies. Three main petrofacies are recognised and on the basis of these petrofacies, a revised correlation of the sandy systems is proposed between the more proximal Ainsa basin, and the more distal Jaca basin sediments, now separated by the Boltana anticline, across which it is impossible to actually trace out individual beds or sandstone packages between both basins. The new correlation scheme, along with the newly identified sediment provenances, changes the current (published) understanding of the Ainsa and Jaca basins evolution and palaeogeography. 2 Acknowledgement Several people have helped me to achieve the goal of completing this PhD, and making this thesis possible. First of all, I would like to express sincere gratitude to my supervisors Prof Kevin T Pickering and Prof Tony Hurford for their encouragement and comments during all stages of my work. I am also indebted to their help regarding matters of academic and non-academic concerns. Special thanks must be given to Dr Andy Carter for his continuous guidance and assistance with the geochronology work. Furthermore, this thesis benefited immensely from the constructive criticism of Prof Rob Hall and Dr Sarah Davies. I greatly appreciate the help received from several people during data generation for this research. Thanks to UCL deep-water research group members, Tom, Nicole and Clare, for helping me out with the fieldwork. Thanks to the staff and lab in-charge of the following laboratories for assisting me with different laboratory techniques: Wolfson Laboratory for Environmental Geochemistry, UCL for carbon analyses; Bloomsbury Environmental Isotope Facility, UCL and Stable Isotope Laboratories, Royal Holloway University of London (RHUL) for stable isotope analyses; Wolfson Archaeological Science Laboratories, UCL for CL imaging; X-Ray Fluorescence Laboratory, RHUL for XRF analyses. A very special note of thanks is due to Dr Joachim Thomas for helping me with the sample collection in Jaca area. This PhD project was jointly funded by the Natural Environmental Research Council (NERC) and Scottish Power under the “Dorothy Hodgkin Postgraduate Award” scheme. Additional financial assistance from Prof Tony Hurford, the UCL Graduate School and the International Association of Sedimentologists (IAS) towards laboratory costs and conference expenses are gratefully acknowledged. Finally, cheers to all my friends in India, Germany and London, who have stood by me through the good and bad times during my PhD, and who have made my stay in UCL (especially Heather, Simon, Tom DJ and Seb) a memorable experience. Last, but not the least, I acknowledge my family for their constant encouragement, enthusiasm and moral support. 3 Table of Contents Page No. Abstract 2 Acknowledgment 3 Table of contents 4 List of figures 8 List of tables 12 List of abbreviations 13 Chapter 1 Introduction 14-20 1.1 Objectives 16 1.2 Methods 19 1.3 Organisation of the thesis 19 Chapter 2 Geology of the Study Area 21-42 2.1 The Eocene - an overview 21 2.2 The Pyrenees 29 2.3 The Ainsa-Jaca basin 33 2.3.1 Stratigraphy and palaeogeography of the Ainsa basin 36 2.3.2 Stratigraphy and palaeogeography of the Jaca basin 38 2.3.3 Correlation framework in the Ainsa and Jaca basins 40 Chapter 3 Materials and Methods 43-75 3.1 Sample acquisitions 43 3.2 Petrography techniques 64 3.3 Geochronology techniques 65 3.3.1 Heavy mineral separation 67 3.3.2 Fission track chronometry 67 3.3.3 U-Pb analysis 71 3.4 Geochemical Techniques 72 4 3.4.1 X-ray fluorescence (XRF) analysis 72 3.4.2 Stable isotope analysis 74 3.4.3 Carbon analysis 74 Chapter 4 Petrography of the Ainsa and Jaca basins 76-111 4.1 Introduction 76 4.2 Framework grains 78 4.2.1 Non-Carbonate Extrabasinal (NCE) 78 4.2.2 Non-Carbonate Intrabasinal (NCI) 78 4.2.3 Carbonate Extrabasinal (CE) 81 4.2.4 Carbonate Intrabasinal (Cl) 81 4.3 Petrography of the Ainsa basin systems 89 4.3.1 Fosado system 89 4.3.2 Arro system 89 4.3.3 Gerbe system 90 4.3.4 Banaston system 91 4.3.5 Ainsa system 91 4.3.6 Morillo system 92 4.3.7 Guaso system 93 4.4 Petrography of the Jaca basin systems 93 4.4.1 Torla system 93 4.4.2 Broto system 94 4.4.3 Cotefablo system 94 4.4.4 Banaston system 95 4.4.5 Jaca system 95 4.5 Diagenesis 96 4.6 Petrofacies 99 4.7 Compositional trends 105 4.8 Corrections for indistinguishable limeclasts 109 5 Chapter 5 Geochronology and Geochemistry of the proximal Ainsa basin 112-142 5.1 Introduction 112 5.2 Geochemistry 113 5.2.1 Major element composition 113 5.2.2 Trace element composition 124 5.3 Geochronology 131 5.3.1 Fission Track (FT) data 131 5.3.2 U-Pb data 135 5.3.3 Zircon structure 139 Chapter 6 Isotopic Signatures of Foraminifera 143-155 6.1 Introduction 143 6.2 Results 144 6.3 Preservation of isotopic signal 149 6.4 Ainsa basin vs. global isotopic signal 152 6.5 Summary 155 Chapter 7 Discussion 156-182 7.1 Tectonic setting 15 6 7.2 Provenance 159 7.3 Hinterland evolution and sediment dispersal 163 7.4 Evolution of basinal sediments 169 7.4.1 Ainsa basin 169 7.4.2 Jaca basin 171 7.5 Revised correlation of sandy systems of the Ainsa and Jaca basins 174 Chapter 8 Conclusions 183-187 8.1 Provenance and evolution 183 8.2 Correlation and palaeogeography 185 8.3 Recommendation for future work 186 6 References 188 Appendix I U-Pb geochronologic analyses of the Ainsa basin 216 detrital zircons Appendix II Fission-Track age calculation 230 List of publications 236 7 List of Figures Chapter I Page No. Figure 1.1 Diagram illustrating the range of processes and their 15 interaction in deep water environments. Figure 1.2 World map showing principal frontier areas for 16 hydrocarbon exploration. Chapter 2 Figure 2.1 Relief map of the Iberian Peninsula. 22 Figure 2.2 An overview of the main bio-, magneto-, chemo-, and 23 other events in the Eocene epoch. Figure 2.3 World palaeogeography during initiation and culmination 23 of the Eocene epoch. Figure 2.4 Simplified palaeogeographic map of south-western 26 Europe during the Early to Middle Ypresian (55-51 Ma). Figure 2.5 Simplified palaeogeographic map of south-western 27 Europe during the Late Lutetian (44-41 Ma). Figure 2.6 Simplified palaeogeographic map of south-western 29 Europe during the Late Rupelian (32-29 Ma). Figure 2.7 (A) Structural cross section along the ECORS Pyrenees 31 line. (B) Simplified structural map of the Pyrenees showing the main tectonic zones. Figure 2.8 Simplified geological map of the Pyrenees and southern 34 foreland basins, also showing location of the study area. Figure 2.9 Palaeogeographic reconstructions of the Ainsa and Jaca 35 basins and surrounding areas during the early Lutetian. Figure 2.10 General stratigraphy of the Ainsa basin. 37 Figure 2.11 Stratigraphy of the Jaca basin. 39 Figure 2.12 Schematic diagram showing different correlations 41 proposed for the turbidite systems of the Ainsa and Jaca basins. Figure 2.13 Correlation framework of the sandstone (turbidite) 42 systems in the Ainsa and Jaca basins prior to this thesis.