University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 8-2018 SAND DEPOSIT MAPPING AND AEOLIAN MORPHOLOGIES AS CLUES FOR IDENTIFYING ORIGINS OF DARK SAND IN AEOLIS DORSA, MARS Ariana Sterling Boyd University of Tennessee, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Recommended Citation Boyd, Ariana Sterling, "SAND DEPOSIT MAPPING AND AEOLIAN MORPHOLOGIES AS CLUES FOR IDENTIFYING ORIGINS OF DARK SAND IN AEOLIS DORSA, MARS. " Master's Thesis, University of Tennessee, 2018. https://trace.tennessee.edu/utk_gradthes/5182 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by Ariana Sterling Boyd entitled "SAND DEPOSIT MAPPING AND AEOLIAN MORPHOLOGIES AS CLUES FOR IDENTIFYING ORIGINS OF DARK SAND IN AEOLIS DORSA, MARS." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Master of Science, with a major in Geology. Devon M. Burr, Major Professor We have read this thesis and recommend its acceptance: Christopher M. Fedo, Liem Thanh Tran Accepted for the Council: Dixie L. Thompson Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) SAND DEPOSIT MAPPING AND AEOLIAN MORPHOLOGIES AS CLUES FOR IDENTIFYING ORIGINS OF DARK SAND IN AEOLIS DORSA, MARS A Thesis presented for the Master of Science Degree The University of Tennessee, Knoxville Ariana Sterling Boyd August 2018 Copyright © 2018 Ariana Sterling Boyd All rights reserved ii DEDICATION To my parents and my role models, Wes and Theonia. To my siblings, Naomi, Anaïs, and Emerson. To my grandmother, Frida. iii ACKNOWLEDGMENTS Acknowledgment is owed to my thesis committee—Drs. Devon Burr, Chris Fedo and Liem Tran—for its assistance, ideas, and edits with this research. Thanks also to the USGS Mars Data Analysis Program (MDAP) for financial support of this project. I’d like to thank all within the university who have provided help and good cheer along the way. This university is full of wonderful people and programs and I feel fortunate to have met so many different people during my time here. Thanks in particular to Earth & Planetary Sciences (EPS) staff Melody Branch, Teresa Parrott, and Angie Staley for their help and patience; to all faculty members from whom I have learned, both in and out of the classroom; and to my undergraduate students over the last few years, from whom I have learned a great deal. Many thanks to Drs. Larry McKay, Hap McSween, and Bill Deane for their time and help with various aspects of my graduate experience. Thanks are also owed to the students in BRIGHT for their envouragement and help. Thanks also to Sarah Stone at the Graduate School for help with formatting this thesis. No words could do justice to the guidance, encouragement, love and support my parents have given me throughout this endeavor. I would not be who or where I am without them. The same goes for my siblings, Naomi, Anaïs and Emerson, three of the best people I know. Emily Nield and Molly Pattullo likely enabled the completion of this thesis through many, many hours of laughter, advice, stories, and love. I feel blessed to have them in my life and am excited to have a front-row seat watching their futures unfold. Thanks to Sam Gwizd for the love, carpools, runs, and support. Thanks to Audrey Martin and Diego Sanchez for many fun evenings and for always being willing to look after my pups. Thanks to my officemates—and especially Jessi Ende, my longtime officemate and birthday buddy—for always being there, even on weekends. I am grateful to my two southern sages, Jeanne and Robyn, for reminding me to laugh and to be strong, and to Tyler Corcoran, who is always able to change the color on my mood ring. Finally, a special thank you to my dogs, Hazel and Dakota, for brightening my days, no matter how good or bad. iv ABSTRACT Dark sand deposits occur at all latitudes on the Martian surface. Sand sources in some regions have been inferred via paleo-wind indicator analyses, sand and source mineralogy comparisons, and climate modeling. However, all known sources are sedimentary, leaving outstanding the question of primary igneous origin(s) of these dark sand deposits. One hypothesis addressing this question is that volcaniclastic deposits are a primary origin of Martian sand. Terrestrial analogs of volcaniclastic units sourcing sand support this hypothesis. However, sand generation has yet to be observed or inferred from any such Martian deposit. This thesis tests this hypothesis via a case study in Aeolis Dorsa, Mars, a locality where sand overlies bedrock consisting of a hypothesized volcaniclastic deposit, the Medusae Fossae Formation (MFF). In addition to the MFF, additional potential external sand sources exist: Elysium Mons, the Cerberus Plains lavas, and the Southern Highlands. To identify likely sand source(s) in Aeolis Dorsa, sand deposits were mapped to address geospatial sand distribution, scour mark orientations were mapped and analyzed to reveal dominant paleo-wind directions, and instances of apparent erosion of bedrock to dark sediment were recorded. Hierarchical clustering analysis of sand distribution revealed preferential sand deposition on the peripheries of the MFF and in the southern depression (where bedrock may be remnant southern highlands material). Hierarchical cluster analysis of scour mark distribution revealed spatial groups of scour marks with consistent paleo-wind directions within groups. Such paleo-wind directions provide no evidence for long-distance sand transport from potential external source regions, but instead provide support for paleo-winds controlled by local topography. Apparent erosion of bedrock to dark sediments occurs in both the MFF (in ~20 localities) and in the southern depression (in over 100 localities), suggesting that both the MFF and bedrock in the southern depression have the potential to generate dark sand. The implication that the MFF has the potential to produce dark sand raises two important possibilities: first, that elsewhere along v the Martian equator the MFF may have produced dark sand, and second, that other friable layered deposits (of which the MFF is one) may also serve as sources of Martian sand. vi TABLE OF CONTENTS 1. Introduction ................................................................................................................... 1 2. Background ................................................................................................................... 3 2.1 Sand generation and transport mechanisms on Mars .............................................. 3 2.2 Sand deposit localities and sources on Mars ........................................................... 4 2.3 The Medusae Fossae Formation ............................................................................. 6 2.4 Martian aeolian bedforms within Aeolis Dorsa .......................................................... 7 2.4.1 Scour marks ....................................................................................................... 8 2.4.2 Common dune forms .......................................................................................... 8 2.5 The Aeolis Dorsa region, Mars ................................................................................. 9 2.5.1 Aeolis Dorsa regional geology ............................................................................ 9 2.5.2 Geologic context: ages and stratigraphic relationships ....................................... 10 2.5.3 Potential sources of sand in Aeolis Dorsa .......................................................... 11 3. Hypotheses ................................................................................................................... 14 4. Data and methods ......................................................................................................... 18 4.1 Data ......................................................................................................................... 18 4.2 Mapping criteria ....................................................................................................... 18 4.2.1 Sand deposit mapping ....................................................................................... 18 4.2.2 Scour mark mapping .......................................................................................... 19 4.2.3 Potential sites of in situ sand generation: HiRISE ............................................... 20 4.3 Hierarchical clustering analyses ............................................................................... 21 4.4 Scour mapping error analysis................................................................................... 23 4.5 Geologic and stratigraphic relationships ................................................................... 24 5. Results and analyses .................................................................................................... 26 5.1 Sand distribution .....................................................................................................