North Gale Landform and the Volcanic Sources of Sediment in Gale Crater, Mars By Jeff Churchill, BSc. Brock University Submitted in partial fulfillment of the requirements for the degree of Master of Science in Earth Sciences Faculty of Earth Sciences, Brock University St. Catharines, Ontario ©2018 i Master of Science (2018) Brock University (Earth Sciences) St Catharines, ON, Canada TITLE: Volcanic Sources of Sediment in Gale Crater, Mars AUTHOR: Jeffrey Churchill, Honours BSc. (Brock University, St. Catharines, Ontario, Canada, 2016) SUPERVISOR: Professor, Dr. Mariek E. Schmidt COMMITTEE: Dr. Frank Fueten, Dr. Kevin Turner NUMBER OF PAGES: 138 ii Abstract An investigation into the origins of a previously unidentified landform north of Gale Crater, Mars (North Gale Landform, NGL) using remotely sensed datasets and morphological mapping has determined that it is a volcanic construct that collapsed and produced a hummocky terrain deposit to the south. Volcaniclastic sediments have been detected in the sedimentary rocks of Gale Crater by APXS. They can be grouped into distinct classes: Jake_M and Bathurst_Inlet. Jake_M are float rocks and cobbles made of igneous sediments with evolved, alkaline compositions and pitted, dusty surfaces. Bathurst_Inlet are least altered potassic basaltic sediments in siltstone sandstone to matrix-supported conglomerates. Simple petrologic models demonstrate there is a need for more than one distinct crystalline source. Bathurst_Inlet class targets are not mantle melts and Jake_M class targets are not differentiated from Bathurst_Inlet or Adirondack. NGL may be one source for the volcaniclastic sediments in Gale Crater. Key words: Mars, Gale Crater, volcanology, geochemistry, petrological modelling iii Acknowledgements I’d like to thank my thesis supervisor Mariek Schmidt for all the help and support that she has given me for the past 2+ years. Mariek has helped me to live out a dream of mine to work in another planet and hopefully contribute something useful to the planetary science community. I’d like to acknowledge the support, advice and ideas that I have received from the rest of my committee: Frank Fueten, and Kevin Turner. I’d like to thank Jon Walmsley for providing me with the imagery and DEMs to get me started. Thanks to my parents, Jeff and Cathy Churchill, the rest of my family and Emily Jones for putting up with me going to school and living at home for so long, it would not have been possible without you guys. I’d also like to thank the rest of the Earth Science grad students at Brock for giving me advice, bouncing ideas around and letting me distract you guys. This work is supported by a Canadian Space Agency Participating Scientist Grant to Schmidt, a Queen Elizabeth II Graduate Scholarship in Science and Technology to Churchill and Brock University Graduate Studies Grants to Churchill. iv Table of Contents Abstract ........................................................................................................................................... iii Acknowledgements ......................................................................................................................... iv List of Tables .................................................................................................................................. viii List of Figures ...................................................................................................................................ix List of Abbreviations ...................................................................................................................... xvi Chapter 1: Introduction ................................................................................................................... 1 Space Exploration ................................................................................................................... 1 Mars Science Laboratory Rover Curiosity .............................................................................. 2 Mars History ........................................................................................................................... 4 Martian Volcanism ................................................................................................................. 8 1.4.1 Redistribution of Volcanic Materials ............................................................................... 9 1.4.2 Collapse Features .......................................................................................................... 12 Gale Crater ........................................................................................................................... 14 Curiosity in Gale Crater ........................................................................................................ 17 Study Purpose ...................................................................................................................... 19 Chapter 2: Volcano and Debris Avalanche Deposit North of Gale Crater, Mars ........................... 20 Introduction ......................................................................................................................... 20 2.1.1 Volcaniclastic Sediments in Gale Crater ........................................................................ 21 2.1.2 North Gale Landform .................................................................................................... 22 v 2.1.3 Dichotomy Boundary Landforms .................................................................................. 24 2.1.4 Impact Craters on Mars ................................................................................................ 25 Methodology ........................................................................................................................ 28 Results .................................................................................................................................. 29 2.3.1 NGL Physical Description .............................................................................................. 29 2.3.2 NGL Related Features.................................................................................................... 37 2.3.3 Other Important Units .................................................................................................. 42 2.3.4 Morphological Map ....................................................................................................... 45 2.3.5 Tectonic Trends ............................................................................................................. 47 Discussion ............................................................................................................................. 51 2.4.1 Origin of North Gale Landform ..................................................................................... 52 2.4.2 Origin of Hummocky Terrain ......................................................................................... 68 2.4.3 Volcanic Debris Avalanche ............................................................................................ 71 2.4.4 Implications for Gale Crater Geology ............................................................................ 77 Conclusions .......................................................................................................................... 79 Chapter 3: Volcanic Sources of Sediment in Gale Crater, Mars ..................................................... 83 Introduction ......................................................................................................................... 83 3.1.1 Igneous Lithologies ....................................................................................................... 86 Methods ............................................................................................................................... 89 Results .................................................................................................................................. 90 vi Discussion ............................................................................................................................. 99 3.4.1 Models ........................................................................................................................ 103 3.4.2 Partial Melting ............................................................................................................. 105 3.4.3 Fractional Crystallization ............................................................................................. 112 3.4.4 Mineral Accumulation ................................................................................................. 115 3.4.5 Summary of Models .................................................................................................... 117 Conclusion .......................................................................................................................... 119 Chapter 4: Summary, Final Discussion and Overall Conclusions ................................................. 122 Summary of Previous Chapters .......................................................................................... 122 Final Discussion and Conclusions ....................................................................................... 123 Limitations of Study ........................................................................................................... 127 Future Work ......................................................................................................................