The Martian Near Surface Environment: Analysis of Antarctic Soils and Laboratory Experiments on Putative Martian Organics

Hdl Handle:
http://hdl.handle.net/10150/195892
Title:
The Martian Near Surface Environment: Analysis of Antarctic Soils and Laboratory Experiments on Putative Martian Organics
Author:
Archer, Paul Douglas
Issue Date:
2010
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:
Understanding the physical properties as well as the potential for organic material in the Martian near-surface environment can give us a glimpse into the history of the site with regards to water, soil formation processes, as well as the conditions necessary for life. This work is done to support the interpretation of data from the Phoenix Mars Lander as well as other past and future landed missions. The Antarctic Dry Valleys are a hyper-arid cold polar desert that is the most Mars-like place on Earth. Soils from two different soil and climate regimes are analyzed to determine their physical properties such as mineralogy, particle size, shape, color, and specific surface area. These data are used to describe the sample locations in Antarctica and infer properties of Martian soils by comparison to Antarctic sites. I find that the particle size distribution can be used to determine the water history of the site and that the behavior of soluble species in the soil can also be used to trace the movement of water through the soil and could be instructive in understanding how soil organic material is processed by the environment. Continuing with the theme of soil organic matter, we revisit the Viking conclusions with regards to organics on Mars and look at the Phoenix data on the same subject. First, we assume that Mars receives organic material from meteoritic infall. These organics will be processed by chemical oxidants as well as UV light down to 200 nm. Chemical oxidation is predicted to produce molecules such as mellitic acid, which could preserve up to 10% of the original organic mass. Using mellitic acid and other similar organic molecules, we irradiate these molecules with Mars-like ultraviolet light, analyzing the gases that come off as irradiation takes place. We find that organic molecules can survive Mars-like UV conditions as layers of UV-resistant organics build up, shielding the remaining organic material. Additionally, the gas products of irradiation depend on the composition of the original organic molecule, implying that even irradiated molecules will carry some information about the composition of the original molecule. Finally, we take this irradiated organic/soil stimulant mixture and analyze it via pyrolysis, similar to the Viking GC/MS and TEGA instruments that are the only instruments operated on Mars capable of detecting organics. We find that the pyrolysis of mellitic acid (and other similar) molecules primarily produces inorganic fragments but that the reduced carbon fragments released depend on the composition of the original organic. However, the introduction of perchlorate, discovered on Mars by the Phoenix Lander, complicates the issue by creating the conditions for molecular oxidation. The high-oxygen content and high pyrolysis temperatures lead to organic combustion during thermal analysis, meaning that, regardless of the initial composition, most soil organics will be oxidized to CO₂ during the detection process. By assuming that organic material was oxidized to CO₂ in the Phoenix and Viking samples. We show that this assumption gives organic concentrations consistent with meteoritic accumulation rates. This finding reopens the possibility for organic molecules in the near-surface environment at the Viking and Phoenix landing sites.
Type:
text; Electronic Dissertation
Keywords:
Antarctica; Habitability; Mars; Organics; Phoenix Mission; Soil Properties
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Planetary Sciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Smith, Peter H.
Committee Chair:
Smith, Peter H.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleThe Martian Near Surface Environment: Analysis of Antarctic Soils and Laboratory Experiments on Putative Martian Organicsen_US
dc.creatorArcher, Paul Douglasen_US
dc.contributor.authorArcher, Paul Douglasen_US
dc.date.issued2010en_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.abstractUnderstanding the physical properties as well as the potential for organic material in the Martian near-surface environment can give us a glimpse into the history of the site with regards to water, soil formation processes, as well as the conditions necessary for life. This work is done to support the interpretation of data from the Phoenix Mars Lander as well as other past and future landed missions. The Antarctic Dry Valleys are a hyper-arid cold polar desert that is the most Mars-like place on Earth. Soils from two different soil and climate regimes are analyzed to determine their physical properties such as mineralogy, particle size, shape, color, and specific surface area. These data are used to describe the sample locations in Antarctica and infer properties of Martian soils by comparison to Antarctic sites. I find that the particle size distribution can be used to determine the water history of the site and that the behavior of soluble species in the soil can also be used to trace the movement of water through the soil and could be instructive in understanding how soil organic material is processed by the environment. Continuing with the theme of soil organic matter, we revisit the Viking conclusions with regards to organics on Mars and look at the Phoenix data on the same subject. First, we assume that Mars receives organic material from meteoritic infall. These organics will be processed by chemical oxidants as well as UV light down to 200 nm. Chemical oxidation is predicted to produce molecules such as mellitic acid, which could preserve up to 10% of the original organic mass. Using mellitic acid and other similar organic molecules, we irradiate these molecules with Mars-like ultraviolet light, analyzing the gases that come off as irradiation takes place. We find that organic molecules can survive Mars-like UV conditions as layers of UV-resistant organics build up, shielding the remaining organic material. Additionally, the gas products of irradiation depend on the composition of the original organic molecule, implying that even irradiated molecules will carry some information about the composition of the original molecule. Finally, we take this irradiated organic/soil stimulant mixture and analyze it via pyrolysis, similar to the Viking GC/MS and TEGA instruments that are the only instruments operated on Mars capable of detecting organics. We find that the pyrolysis of mellitic acid (and other similar) molecules primarily produces inorganic fragments but that the reduced carbon fragments released depend on the composition of the original organic. However, the introduction of perchlorate, discovered on Mars by the Phoenix Lander, complicates the issue by creating the conditions for molecular oxidation. The high-oxygen content and high pyrolysis temperatures lead to organic combustion during thermal analysis, meaning that, regardless of the initial composition, most soil organics will be oxidized to CO₂ during the detection process. By assuming that organic material was oxidized to CO₂ in the Phoenix and Viking samples. We show that this assumption gives organic concentrations consistent with meteoritic accumulation rates. This finding reopens the possibility for organic molecules in the near-surface environment at the Viking and Phoenix landing sites.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectAntarcticaen_US
dc.subjectHabitabilityen_US
dc.subjectMarsen_US
dc.subjectOrganicsen_US
dc.subjectPhoenix Missionen_US
dc.subjectSoil Propertiesen_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.advisorSmith, Peter H.en_US
dc.contributor.chairSmith, Peter H.en_US
dc.contributor.committeememberSmith, Mark A.en_US
dc.contributor.committeememberBoynton, William V.en_US
dc.contributor.committeememberBaker, Victor R.en_US
dc.contributor.committeememberByrne, Shaneen_US
dc.identifier.proquest10882en_US
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