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Investigations of the Martian Mid- Latitudes: Implications for Ground Ice Item Type text; Electronic Dissertation Authors Dundas, Colin Morrisey Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 11/10/2021 01:56:53 Link to Item http://hdl.handle.net/10150/195698 INVESTIGATIONS OF THE MARTIAN MID-LATITUDES: IMPLICATIONS FOR GROUND ICE by Colin Morrisey Dundas _____________________ A Dissertation Submitted to the Faculty of the DEPARTMENT OF PLANETARY SCIENCES In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 2009 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Dissertation Committee, we certify that we have read the dissertation prepared by Colin Morrisey Dundas entitled Investigations of the Martian Mid-Latitudes: Implications for Ground Ice and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy _______________________________________________________________________ Date: June 15, 2009 Alfred S. McEwen _______________________________________________________________________ Date: June 15, 2009 Shane Byrne _______________________________________________________________________ Date: June 15, 2009 H. Jay Melosh _______________________________________________________________________ Date: June 15, 2009 Victor R. Baker _______________________________________________________________________ Date: June 15, 2009 Clement G. Chase Final approval and acceptance of this dissertation is contingent upon the candidate’s submission of the final copies of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement. ________________________________________________ Date: June 15, 2009 Dissertation Director: Alfred S. McEwen 3 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at the University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author. SIGNED: Colin Dundas 4 ACKNOWLEDGEMENTS I owe thanks to many people for their help on the way to this dissertation, starting with my committee. My advisor Alfred McEwen let me get involved in HiRISE and encouraged me to explore interesting problems and think critically. Shane Byrne helped initiate me into quantitative modeling of surface processes. Jay Melosh ran many of the fieldtrips, which might have been the best part of grad school. Clem Chase and Vic Baker were also very helpful. Before I even got to grad school, Oded Aharonson and Bruce Murray helped me get started in Mars surface research. Apparently it stuck. On the official front, I’ve been paid from a University of Arizona TRIF Imaging Fellowship and several of Alfred’s NASA grants; thanks to each of these funding sources. I would also like to thank Icarus for permission to reprint papers in this thesis. The HiRISE team has been a superb scientific environment. I would particularly like to thank Laszlo Keszthelyi, Windy Jaeger, Mike Mellon, Chris Okubo, Moses Milazzo, Nick Thomas and Alexandra Lefort…and that’s certainly leaving out many others. I would also like to thank the targeting specialists and the rest of the uplink, downlink and other staff who helped get the terrific images that I got to use. Kathi Baker and Linda Hickcox made paperwork go away, and Joe Plassman, Terry Forrester and Dean Jones gave me the chance to bathe in the unholy glow of two 30-inch monitors for several years, although it didn’t help my tan. Fieldtrips (and scouting for fieldtrips) have given me some of my best memories and experiences from grad school. I would particularly like to thank C. F. Hill for a valuable field demonstration of angle of repose processes, and Jason, Jani and Joe for proper handling of The Baja Incident. They know why. My original housemates (John Keller, Curtis Cooper and Carl Hergenrother) let me move into Mabel House, and my later housemates Tamara Goldin, Brian Jackson and Tom Schad were good friends and kept it a fun place to live. Although it is not just a risk but a certainty that I’ll leave someone out, I would like to thank many other friends who made the last few years good ones. A number of elders helped set me on the (possibly) right path: Jason Barnes (deserves a special nod for smoothing the transition from Caltech to Arizona), Gwen Barnes, Ralph Lorenz, Dave O’Brien, Jani Radebaugh, Chris Schaller, Joe Spitale and Ingrid Daubar Spitale. David Choi was my officemate for many years, and was always ready to drop everything and conduct bizarre miscellaneous research projects. Doug Archer, Nicole Baugh, Mike Bland, Jade Bond, Sarah Hörst, Kelly Kolb, Dan Morman and Catherine Neish were also good friends. Thank you all, variously, for Beers, poker, hikes, field excursions, sports discussions, Tim Tams and general good company, which has made the last five years fly by. I’m sure I forgot someone. Blame it on the last minute. Last but definitely not least, my parents Steve and Judy and my brother Guthrie deserve a big thank-you for their support over the years. 5 DEDICATION To my parents. 6 TABLE OF CONTENTS LIST OF FIGURES.........................................................................................................8 LIST OF TABLES ..........................................................................................................9 ABSTRACT..................................................................................................................10 CHAPTER 1: INTRODUCTION ..................................................................................12 1.1 Mars: A Periglacial Planet..................................................................................12 1.2 Description of Work ..........................................................................................15 CHAPTER 2: THEORY OF SUBLIMATION BY FREE CONVECTION IN RELATION TO EXPERIMENTAL DATA AND THE MARTIAN SURFACE ...........19 2.1 Background .......................................................................................................19 2.2 Free Convection.................................................................................................20 2.3 Comparison of Theory and Experiments ............................................................26 CHAPTER 3: MODELING SUBLIMATION OF ICE EXPOSED BY NEW IMPACTS IN THE MARTIAN MID-LATITUDES........................................................................33 3.1 Abstract .............................................................................................................33 3.2 Introduction .......................................................................................................34 3.3 Thermal and Sublimation Model........................................................................36 3.3.1 Thermal Model ...........................................................................................36 3.3.2 Sublimation Model......................................................................................46 3.4 Model Inputs......................................................................................................51 3.4.1 Model Scenarios..........................................................................................51 3.4.2 Input parameters..........................................................................................54 3.5 Results...............................................................................................................59 3.6 Discussion .........................................................................................................63 3.6.1 Model Uncertainties and Interpretation........................................................63 3.6.2 Dust Content of Exposed Ice.......................................................................66 3.6.3 Implications for Ground Ice on Mars...........................................................73 CHAPTER 4: AN ASSESSMENT OF EVIDENCE FOR PINGOS ON MARS USING HIRISE .........................................................................................................................78 4.1 Abstract .............................................................................................................78 4.2 Introduction .......................................................................................................79 4.3 Theoretical Considerations.................................................................................83 4.3.1 Scaling........................................................................................................83
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