Investigating Evidence of Geologically Recent Liquid Water on Mars

Hdl Handle:
http://hdl.handle.net/10150/193706
Title:
Investigating Evidence of Geologically Recent Liquid Water on Mars
Author:
Kolb, Kelly Jean
Issue Date:
2009
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.
Abstract:
Geologically young gullies have been proposed to be evidence of recent liquid water on Mars. This dissertation details work I have done to address issues surrounding the Martian gullies and recent water on Mars. In order to determine the elevations at which gullies occur, I created a set of Interactive Data Language programs and Unix C-shell scripts to coregister Mars Orbiter Laser Altimeter topography with high resolution Mars images. My scripts represent the first public method that does this. Recently, the Mars Orbiter Camera detected changes in the form of new bright deposits in two gullies. The High Resolution Imaging Science Experiment (HiRISE) camera detected more gullies with bright deposits. I used my scripts to identify some of the best candidates for liquid water formation based on their shallow average slopes. A Digital Elevation Model (DEM) was produced using HiRISE stereo images of my selected candidates in Hale Crater. I model two gullies with bright slope deposits in Hale Crater and find that both water-rich and sediment-rich flows could reproduce the bright deposits’ locations and morphologies. Since liquid water is rarely stable on Mars today, I suggest that dry flows formed the bright deposits. The channel gradient where flows deposit, the apex slope, can tell us whether a flow was likely dry and non-fluidized (slopes ~21°) or fluidized (shallower slopes). I measured the apex slope of 75 gullies located in five HiRISE DEMs. I find that 72% of the gullies studied were likely emplaced by a fluidized flow. I also find that modified gullies are more likely to have a fluidized emplacement than relatively fresh gullies. My results suggest that there is no evidence requiring water-rich flows in gullies today. Understanding the concept of water on Mars is crucial to understanding NASA’s Mars Exploration Strategy, “Follow the Water.” I undertook a study investigating alternative conceptions about water on Mars held by middle school science teachers to understand what they hear when scientists say “water on Mars.” All study participants had alternative conceptions about water on Mars. I suggest focus topics for space science education programs.
Type:
text; Electronic Dissertation
Keywords:
Alternative Conceptions; Coregistration; Gullies; Mars; Water
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Planetary Sciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
McEwen, Alfred S.
Committee Chair:
McEwen, Alfred S.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleInvestigating Evidence of Geologically Recent Liquid Water on Marsen_US
dc.creatorKolb, Kelly Jeanen_US
dc.contributor.authorKolb, Kelly Jeanen_US
dc.date.issued2009en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © 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.en_US
dc.description.abstractGeologically young gullies have been proposed to be evidence of recent liquid water on Mars. This dissertation details work I have done to address issues surrounding the Martian gullies and recent water on Mars. In order to determine the elevations at which gullies occur, I created a set of Interactive Data Language programs and Unix C-shell scripts to coregister Mars Orbiter Laser Altimeter topography with high resolution Mars images. My scripts represent the first public method that does this. Recently, the Mars Orbiter Camera detected changes in the form of new bright deposits in two gullies. The High Resolution Imaging Science Experiment (HiRISE) camera detected more gullies with bright deposits. I used my scripts to identify some of the best candidates for liquid water formation based on their shallow average slopes. A Digital Elevation Model (DEM) was produced using HiRISE stereo images of my selected candidates in Hale Crater. I model two gullies with bright slope deposits in Hale Crater and find that both water-rich and sediment-rich flows could reproduce the bright deposits’ locations and morphologies. Since liquid water is rarely stable on Mars today, I suggest that dry flows formed the bright deposits. The channel gradient where flows deposit, the apex slope, can tell us whether a flow was likely dry and non-fluidized (slopes ~21°) or fluidized (shallower slopes). I measured the apex slope of 75 gullies located in five HiRISE DEMs. I find that 72% of the gullies studied were likely emplaced by a fluidized flow. I also find that modified gullies are more likely to have a fluidized emplacement than relatively fresh gullies. My results suggest that there is no evidence requiring water-rich flows in gullies today. Understanding the concept of water on Mars is crucial to understanding NASA’s Mars Exploration Strategy, “Follow the Water.” I undertook a study investigating alternative conceptions about water on Mars held by middle school science teachers to understand what they hear when scientists say “water on Mars.” All study participants had alternative conceptions about water on Mars. I suggest focus topics for space science education programs.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectAlternative Conceptionsen_US
dc.subjectCoregistrationen_US
dc.subjectGulliesen_US
dc.subjectMarsen_US
dc.subjectWateren_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePlanetary Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorMcEwen, Alfred S.en_US
dc.contributor.chairMcEwen, Alfred S.en_US
dc.contributor.committeememberBaker, Victor R.en_US
dc.contributor.committeememberByrne, Shaneen_US
dc.contributor.committeememberPelletier, Jonathan D.en_US
dc.contributor.committeememberRichardson, Randall M.en_US
dc.identifier.proquest10549en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.