Quantification of terrestrial weathering and contamination in meteorites recovered in the Sultanate of Oman Inauguraldissertation der Philosophisch-naturwissenschaftlichen Fakultät der Universität Bern Vorgelegt von Florian Johann Zurfluh von Isenthal, UR Leiter der Arbeit: PD Dr. Beda A. Hofmann, Naturhistorisches Museum der Burgergemeinde Bern Ko-Leiter: PD Dr. Edwin Gnos, Muséum d’Histoire Naturelle de la Ville de Genève Ko-Leiter: Dr. Urs Eggenberger, Institut für Geologie, Universität Bern Koreferent: Prof. Dr. Jochen Schlüter, Mineralogisches Museum, Universität Hamburg Quantification of terrestrial weathering and contamination in meteorites recovered in the Sultanate of Oman Inauguraldissertation der Philosophisch-naturwissenschaftlichen Fakultät der Universität Bern Vorgelegt von Florian Johann Zurfluh von Isenthal, UR Leiter der Arbeit: PD Dr. Beda A. Hofmann, Naturhistorisches Museum der Burgergemeinde Bern Ko-Leiter: PD Dr. Edwin Gnos, Muséum d’Histoire Naturelle de la Ville de Genève Ko-Leiter: Dr. Urs Eggenberger, Institut für Geologie, Universität Bern Koreferent: Prof. Dr. Jochen Schlüter, Mineralogisches Museum, Universität Hamburg Von der Philosophisch-naturwissenschaftlichen Fakultät angenommen. Der Dekan: Bern, 14.12.2012 Prof. Dr. Silvio Decurtins Acknowledgments Acknowledgments I will fondly keep in mind the years I could participate in the Omani-Swiss meteorite search and research project with all those positive and informative moments. In this section I would like to thank all the people, who provided considerable help to my PhD-Thesis and thus are responsible for the good vibrations: First of all, I have to thank the leader of the project and my main supervisor, Beda A. Hofmann. His infective inquisitiveness to understand every detail, his broad knowledge of mineralogy, optical microscopy and his creative way to solve problems helped to find a path out of many labyrinths. I’m especially grateful for his time and patience he invested in the extremely detailed corrections of my written work or the endless performance of HHXRF analyses on meteorites. I am also grateful for the possibility to participate at several events at the Natural History Museum such as the public nights at the museum. My second supervisor, Edwin Gnos, is thanked for sharing his wide knowledge in geology of Oman, geology in general and electron microanalysis. His childish-funny, inquiring habit and well-trained eyes enriched the experience during field- and laboratory-work. I enjoyed also every working-visit at the Natural History Museum of Geneva. The third supervisor, Urs Eggenberger, I thank for his confident behavior and since he was not a meteorite-researcher before, providing a view from another perspective. His critical comments, his immense experience in X-ray analytics, data logging and database expanded significantly the dimension of the project. I appreciate also the possibility to attend his coURSes, which widened my horizon. A fundamental part of the thesis presented here is the fieldwork, which I could complete in 2009, 2009/2010 and 2012. I would like to thank the Directors of the Directorate General of Minerals, Ministry of Commerce and Industry: Salim Omar Abdullah Al-Ibrahim, Salim Al- Buseidi, Sami Al Zubaidy and Akram Hassan Abdullah Al-Murazza for the permission and aid during fieldwork. Mohammed Al-Suleimani and Khalid Al-Tobi are thanked for bureaucratic and logistical support. It was always pleasant to be a guest in the beautiful and friendly Sultanate of Oman. I am grateful to the fieldwork participants for the help with finding meteorites, cooking delicious menus, disputes about all kind of topics and identification of stars at night. This includes: Ali Al Rajhi, Ali Al-Kathiri, André Piuz, Annette Bretscher, Beda Hofmann, Christian Meister, Christoph Opitz, Edwin Gnos, Elise Wimmer, Emilie Janots, Frank Preusser, Jan Walbrecker, Karl Wimmer, Mariana Cosarinsky, Martin Fisch, Mathias M. M. Meier, Mohammed Al-Ayrami, Mohammed Al-Battashi, Musallam Al-Maashani, Nathalie Dalcher, Nicolas Greber, Reto Trappitsch, Salim Al-Shahri, Salim Bakhit Al-Kathiri, Silvio Lorenzetti, Thomas Rosenberg and Urs Eggenberger. To my precursor, Ali Al-Kathiri, I would like to say shukran for the support in the field, answering my questions, placement of the temperature logger in mid June in the middle of 5 Acknowledgments the hot desert, translation of the summary into Arabic and for all the interesting stories he told us at tasty Omani dinners he had prepared for us during fieldwork. Nicolas Greber is thanked for the great analytical support (XRD, HHXRF, SEM, EMP, Raman and MC-ICP-MS) as well as for the fruitful discussions. Fieldwork was sustainable, not only due to his fresh bread, fantastic. The hundreds of well-polished thin sections and some special whishes were fulfilled by the great technician team of the Institute of Geological Science, University Bern. Here I would like to thank in particular Vreni Jakob, Thomas Aebi, Stephan Brechbühl, Thomas Siegenthaler and Adrian Liechti. Countless hours I used the electron microprobe at the Institute of Geological Sciences, University of Bern, where Martin Robyr was always ready to help if a problem arrived. Marco Herwegh, Mike Härtel, Alex Wetztel, Katja Lehmann and Karl Ramseyer is thanked for their help with small issues occurred at the SEM. Several times I used the cathode luminescence device of the Natural History Museum at Geneva and could profit from the experience of Pierre Alain and train French, English and German at once. To find the best usage of the handheld XRF device and other technical support or share of knowledge I thank the “Niton-guys” Marc Dupayrat, Roland Bächli, Stan Piorek and Björn Klaue. The water-soluble salt study benefited from the rock-water interaction team of the Institute of Geological Sciences, Uni Bern. I thank Nick Waber, Ruth Mäder, Priska Bähler, Stephan Weissen and Urs Mäder for the support during laboratory and analytical work. Today, geology without isotopes is not serious. I thank Igor Villa and Dea Vögelin for the assistance during the Sr isotope investigations. Radiocarbon analyses for terrestrial age determination were performed by Tim Jull and Marlene Giscard at the NSF-Arizona AMS Laboratory, University of Arizona, Tucson. Richard Greenwood did the oxygen isotope analyses needed for the classification of the special meteorites. Office mates Christoph Wanner and Christine Lemp is thanked for help during preparation of XRF samples and the XRF analyzes itself, as well as the climate in the office. Visits of Dani Kurz where also pleasant and helped for example to develop the structure of the database. The staff of Natural History Museum of Bern, Ursula Menkveld-Gfeller, Bärni Hostettler, Peter Vollenweider, Maria Lauper and Hannes Bauer, I thank for hospitality and help at the Museum. I thank Uli Linden for EDV support and door opening at late night work. Werner Zauggs help at computer and database issues is acknowledged. 6 Acknowledgments Administrative help by Sarah Antenen, Barbara Grose, Tabea Zimmermann and Isabelle Jobin is appreciated. Ivan Mercollis effort to find a reflected light microscopy for my office and sharing his fundamental knowledge of the Sultanate of Oman is respected. Marc Jost, Jochen Schlüter, Rico Mettler, Luici Folco, Carlole Cordier, Uli Ott and Susanne Schwenzer loaned, provided or helped to find meteorite and/or soil samples from other localities than Oman that were needed for our studies. Flat mate Dorian Gaar is thanked for recording television emissions (dealing partly with geology/meteoritics) and the help to solve some illustrator issues. Questions concerning ArcGIS software were answered by Dirk Rike-Zapp and especially Rafael Caduff. This clever boy helped also solving a lot of other (computer) problems. Matthias Bieri is thanked for drawing the raw figure of the synopsis and a movie that shows the terrestrial history of an ordinary chondrite. Finally, I would like to thank all other people from the University, the Monday-soccer team, namely Mike Härtel and Sam Gilgen, collegues, friends and family for the activations not directly related to the thesis providing refreshing pauses between the work. Discussions with not-experts helped to clarify the ideas. The thesis was supported by Swiss National Science Foundation grants 119937 and 137924 entitled “Meteorite accumulations of Arabia”. شكرا 7 8 Contents Contents Acknowledgements 5 Summary 11 Arabic summary 14 Abbreviations 19 Chapter 1: Introduction and background 21 1.1. Meteorites 23 1.2 . Weathering of hot desert meteorites 24 1.3. Goals of the study 25 1.4. Geographical and geological settings of Oman 27 1.5. Present climate and climate history of Oman 29 1.6. Meteorite search areas 30 1.7. Meteorites from Oman 31 1.8. General goals of the Omani-Swiss meteorite project 32 1.9. Meteorite names 34 1.10. Suited surfaces for meteorite recovery in central Oman 36 1.11. Weather observations 40 1.12. References 41 Chapter 2: Weathering and strontium contamination of meteorites recovered in the Sultanate of Oman 49 2.1. Introduction 52 2.2. The Omani-Swiss meteorite search and research project 52 2.3. Weathering 55 2.4. Strontium in hot desert meteorites 57 2.5. Acknowledgments 59 2.6. References 59 Chapter 3: Evaluation of the utility of handheld XRF in meteoritics 61 3.1. Introduction 64 3.2. Methods 65 3.3. Results 73 3.4. Discussion 80 3.5. Conclusions 94 3.6. Acknowledgments 94 3.7. References 95 Chapter 4: Chemical contamination and macroscopic weathering features in meteorites from Oman and other hot deserts 101 4.1. Introduction 104 4.2. Samples and analyses 106 9 Contents 4.3. Results 109 4.4. Discussion 117 4.5. Conclusions 129 4.6. Acknowledgments 130 4.7. References 130 Chapter 5: “Sweating meteorites” – water-soluble salts and temperature variation in ordinary chondrites and soil from the hot desert of Oman 137 5.1. Introduction 140 5.2. Samples and analytical techniques 143 5.3. Results 148 5.4. Discussion 165 5.5. Conclusions 189 5.6.