The Origin of Mantle Xenoliths in Tertiary Alkaline Basalts, British Columbia, Canada: Implications for Convergent Plate Margin Geodynamic and Petrogenetic Processes
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University of Windsor Scholarship at UWindsor Electronic Theses and Dissertations Theses, Dissertations, and Major Papers 1-11-2016 The origin of mantle xenoliths in Tertiary alkaline basalts, British Columbia, Canada: Implications for convergent plate margin geodynamic and petrogenetic processes Eyal Friedman University of Windsor Follow this and additional works at: https://scholar.uwindsor.ca/etd Recommended Citation Friedman, Eyal, "The origin of mantle xenoliths in Tertiary alkaline basalts, British Columbia, Canada: Implications for convergent plate margin geodynamic and petrogenetic processes" (2016). Electronic Theses and Dissertations. 5637. https://scholar.uwindsor.ca/etd/5637 This online database contains the full-text of PhD dissertations and Masters’ theses of University of Windsor students from 1954 forward. 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The origin of mantle xenoliths in Tertiary alkaline basalts, British Columbia, Canada: Implications for convergent plate margin geodynamic and petrogenetic processes By Eyal Friedman A Thesis Submitted to the Faculty of Graduate Studies through the Department of Earth and Environmental Sciences in Partial Fulfillment of the Requirements for the Degree of Master of Science at the University of Windsor Windsor, Ontario, Canada 2015 © Eyal Friedman The origin of mantle xenoliths in Tertiary alkaline basalts, British Columbia, Canada: Implications for convergent plate margin geodynamic and petrogenetic processes by Eyal Friedman APPROVED BY: _____________________________________________________ Dr. B. Zielinski, External Examiner Department of Biological Sciences _____________________________________________________ Dr. I. Samson, Internal Examiner Department of Earth and Environmental Sciences _____________________________________________________ Dr. A. Polat, Advisor Department of Earth and Environmental Sciences December 17, 2015 Declaration of Co-Authorship / Previous Publication I. Co-Authorship Declaration I hereby declare that this thesis incorporates material that is result of joint research, as follows: The collaboration occurs in Chapters 1-9 of this thesis. These chapters contain material that has been accepted for publication. Field work was conducted with Ali Polat. Robert Frei assisted with radiogenic isotope analyses. Ali Polat, Derek Thorkelson and Robert Frei contributed to the manuscript by means of criticism and revision. With these exceptions, field observations, laboratory analyses, data interpretation, key ideas and manuscript preparation were performed by the author. I am aware of the University of Windsor Senate Policy on Authorship and I certify that I have properly acknowledged the contribution of other researchers to my thesis, and have obtained written permission from each of the co-author(s) to include the above material(s) in my thesis. I certify that, with the above qualification, this thesis, and the research to which it refers, is the product of my own work. II. Declaration of Previous Publication This thesis includes 1 original paper that has been accepted for publication in a peer reviewed journal, as follows: iii Thesis Chapter Publication Title/Full Citation Publication Status* Eyal Friedman (60%), Ali Polat (20%), Derek Thorkelson (10%), Robert Frei (10%), Formation of the subcontinental lithospheric mantle Accepted for Publication Chapters 1-9 beneath southern British Columbia, (Gondwana Research) Canada, at a convergent plate margin: Evidence from trace element geochemistry of mantle xenoliths I certify that I have obtained a written permission from the copyright owner(s) to include the above published material(s) in my thesis. I certify that the above material describes work completed during my registration as graduate student at the University of Windsor. I declare that, to the best of my knowledge, my thesis does not infringe upon anyone’s copyright nor violate any proprietary rights and that any ideas, techniques, quotations, or any other material from the work of other people included in my thesis, published or otherwise, are fully acknowledged in accordance with the standard referencing practices. Furthermore, to the extent that I have included copyrighted material that surpasses the bounds of fair dealing within the meaning of the Canada Copyright Act, I certify that I have obtained a written permission from the copyright owner(s) to include such material(s) in my thesis. I declare that this is a true copy of my thesis, including any final revisions, as approved by my thesis committee and the Graduate Studies office, and that this thesis has not been submitted for a higher degree to any other University or Institution. iv Abstract The Tasse basalts of southeastern British Columbia, Canada, are host to a variety of mantle xenoliths consisting predominantly of spinel lherzolite with minor dunite and pyroxenite. On the basis of REE patterns, the xenoliths are divided into three groups reflecting varying degrees of mantle metasomatism: (1) Group 1; concave-up LREE patterns; (2) Group 2; flat to moderately LREE-enriched patterns; and (3) Group 3; strongly LREE-enriched patterns. The majority of xenolith are enriched in LILE, LREE, U, Th, Pb, and Sr, and depleted in HFSE and HREE. These geochemical characteristics are consistent with a sub-arc mantle source. The Tasse lavas are compositionally alkaline basalts and display OIB-like trace element patterns. They have positive εNd (+3.8 to +5.5) values, with 338−426 Ma depleted mantle model ages, and display OIB-like Nd, Sr and Pb isotopic compositions. The Sr−Nd−Pb isotope and trace element characteristics suggesting that they originated from an upwelling asthenospheric mantle source. v This thesis is dedicated to my parents, Martin and Eva, and my brother, Tal, for all of their love, encouragement and support through this journey. This thesis is also in loving memory of my best friend Andrew Avetikov. You will forever be in my memories and in my heart. April 2, 1986 – November 9, 2013 vi Acknowledgements This thesis has been a long time coming. This journey would not have been possible without the help of Dr. Ali Polat. I would like to thank Dr. Polat for his guidance and patience over the past few years through this process. I would also like to thank him for giving me this wonderful opportunity. I would also like to thank Dr. Iain Samson for sharing his expertise in petrography and mineralogy. His insights allowed me to further develop key concepts in my research and studies. Special thanks go to Melissa Price and the staff at GLIER for all their help with laboratory equipment and processes. Thank you to Dr. Barb Zielinski for being a part of my committee and giving me feedback and constructive criticism during my thesis proposal and defense. A final thank you goes to all of my graduate peers who have had to put up with me over the past few years. I appreciate all of the help you have given me and wish you the best with your areas of research. vii Table of Contents Declaration of Co-Authorship/Previous Publication..........................................................iii Abstract................................................................................................................................v Dedication...........................................................................................................................vi Acknowledgements............................................................................................................vii List of Tables.......................................................................................................................x List of Figures.....................................................................................................................xi Chapter 1. Introduction........................................................................................................1 Chapter 2. Regional geology................................................................................................4 Chapter 3. Geology of the study area...................................................................................7 Chapter 4. Sampling.............................................................................................................9 Chapter 5. Methodology....................................................................................................10 5.1. Major and trace element analyses........................................................................10 5.2. Strontium, neodymium and lead isotope analyses...............................................11 Chapter 6. Petrography......................................................................................................13 6.1. Mantle xenoliths...................................................................................................13 6.2. Alkaline basalts....................................................................................................14