Matching Items (37)
Description
Ascraeus Mons (AM) is the northeastern most large shield volcano residing in the Tharsis province on Mars. AM has a diameter of ~350 km and reaches a height of 16 km above Mars datum, making AM the third largest volcano on Mars. Previous mapping of a limited area of these volcanoes using HRSC images (13-25 m/pixel) revealed a diverse distribution of volcanic landforms within the calderas, along the flanks, rift aprons, and surrounding plains. The general scientific objective for which mapping was based was to show the different lava flow morphologies across AM to better understand the evolution and geologic history.
A 1: 1,000,000 scale geologic map of Ascraeus Mons was produced using ArcGIS and will be submitted to the USGS for review and publication. Mapping revealed 26 units total, broken into three separate categories: Flank units, Apron and Scarp units, and Plains units. Units were defined by geomorphological characteristics such as: surface texture, albedo, size, location, and source. Defining units in this manner allowed for contact relationships to be observed, creating a relative age date for each unit to understand the evolution and history of this large shield volcano.
Ascraeus Mons began with effusive, less viscous style of eruptions and transitioned to less effusive, more viscous eruptions building up the main shield. This was followed by eruptions onto the plains from the two main rift aprons on AM. Apron eruptions continued, while flank eruptions ceased, surrounding and embaying the flanks of AM. Eruptions from the rifts wane and build up the large aprons and low shield fields. Glaciers modified the base of the west flank and deposited the Aureole material. Followed by localized recent eruptions on the flanks, in the calderas, and small vent fields. Currently AM is modified by aeolian and tectonic processes. While the overall story of Ascraeus Mons does not change significantly, higher resolution imagery allowed for a better understanding of magma evolution and lava characteristics across the main shield. This study helps identify martian magma production rates and how not only Ascraeus Mons evolved, but also the Tharsis province and other volcanic regions of Mars.
A 1: 1,000,000 scale geologic map of Ascraeus Mons was produced using ArcGIS and will be submitted to the USGS for review and publication. Mapping revealed 26 units total, broken into three separate categories: Flank units, Apron and Scarp units, and Plains units. Units were defined by geomorphological characteristics such as: surface texture, albedo, size, location, and source. Defining units in this manner allowed for contact relationships to be observed, creating a relative age date for each unit to understand the evolution and history of this large shield volcano.
Ascraeus Mons began with effusive, less viscous style of eruptions and transitioned to less effusive, more viscous eruptions building up the main shield. This was followed by eruptions onto the plains from the two main rift aprons on AM. Apron eruptions continued, while flank eruptions ceased, surrounding and embaying the flanks of AM. Eruptions from the rifts wane and build up the large aprons and low shield fields. Glaciers modified the base of the west flank and deposited the Aureole material. Followed by localized recent eruptions on the flanks, in the calderas, and small vent fields. Currently AM is modified by aeolian and tectonic processes. While the overall story of Ascraeus Mons does not change significantly, higher resolution imagery allowed for a better understanding of magma evolution and lava characteristics across the main shield. This study helps identify martian magma production rates and how not only Ascraeus Mons evolved, but also the Tharsis province and other volcanic regions of Mars.
ContributorsMohr, Kyle James (Author) / Williams, David A. (Thesis advisor) / Christensen, Phil R (Thesis advisor) / Clarke, Amanda (Committee member) / Arizona State University (Publisher)
Created2017
Description
Many shallow craters near the Spirit Mars Exploration Rover landing site contain asymmetric deposits of windblown sediments which could indicate the predominant local wind direction at the time of deposition or redistribution. Wind tunnel simulations and field studies of terrestrial craters were used to determine trends in deposition as a function of crater morphometry and wind direction. Terrestrial analog field work at the Amboy lava field, Mojave Desert, California, included real-time wind measurements and assessments of active sediment deposition in four small (<100 m) craters. Preliminary results indicate that reverse flow or stagnant wind and deposition on the upwind side of the crater floor occurs in craters with depth-to-diameter (d/D) ratios ≥0.05. Measurements taken within a crater of d/D of ~0.02 do not indicate reverse flow. Therefore, reverse flow is expected to cease within a d/D range of 0.02 to 0.05, resulting in wind movement directly over the crater floor in the downwind direction with no asymmetric sediment deposition. Wind tunnel simulations using six crater models, including a scaled model of a crater from the Amboy lava field, were completed to assess the wind flow in and around craters as a function of crater morphometry (depth, diameter). Reverse flow occurred in craters with d/D ratios ≥0.033, resulting in sediment deposition in the upwind portion of the crater floor. Visual observations of a crater with a d/D of ~0.020 did not indicate reverse flow, similar to the results of field studies; therefore, reverse flow appears to cease within a d/D range of 0.020 to 0.033. Craters with asymmetric aeolian deposits near the Mars Spirit landing site have d/D ratios of 0.034 to 0.076, suggesting that reverse flow occurs in these craters. Thus, the position of windblown sediments in the northwest parts of the crater floors would indicate prevailing winds from the northwest to the southeast, consistent with late afternoon winds as predicted by the Mars Regional Atmospheric Modeling System (MRAMS) circulation model.
ContributorsKienenberger, Rebekah (Author) / Greeley, Ronald (Thesis advisor) / Christensen, Philip R. (Philip Russel) (Committee member) / Whipple, Kelin (Committee member) / Arizona State University (Publisher)
Created2011
Description
Planetary mineralogy provides important clues about a planet’s geologic history, specifically how the planet first solidified and what geological processes have taken place since. I used spectral and composition data from the Mars Science Laboratory Curiosity rover to study some of the most recent geologic events on Mars. I also used modeled mineralogy of hypothetical exoplanets to understand the initial crystallization of exoplanets. Orbital data of Mt. Sharp, a ~5 km tall mound of sedimentary material, in Gale crater suggests that minerals associated with liquid water are present. These minerals, such as hydrated Mg-sulfates that are left behind as water evaporates, likely represent the beginning of Mars’ transition from a warm wet planet to the cold dry planet it is today.To understand how the mineralogy of Mt. Sharp changed, I used data from the Mastcam instrument on Curiosity to collect visible to near-infrared spectra of rocks from Vera Rubin Ridge and the Carolyn Shoemaker formation. Additionally, I collected laboratory spectra of powered binary mineral mixtures to understand how common minerals such as plagioclase, pyroxene, and hematite might obscure the spectral features of phyllosilicates and Mg-sulfates. Lastly, to better understanding Mars’ mineralogy, I analyzed numerous mixtures with Mg-sulfates in a nitrogen filled glovebox to better represent some of the environmental conditions of present-day Mars.
Minerals such as phyllosilicates and Mg-sulfates, often referred to as secondary minerals, are only found on planets that have experienced alteration since the planet first solidified. The current level of understanding of Martian mineralogy has only been obtained after decades of sending numerous orbital and landed missions with intricate science instruments. But there is not this level of understanding for all planets, and especially not for planets outside of the solar system. Using modeled mineralogy, I deciphered the order in which primary minerals (i.e., olivine, pyroxenes, and plagioclase) could have formed as exoplanets first solidified. Understanding the mineralogy of planetary bodies gives insight into the geologic history of processes that cannot be seen, because they are no longer occurring, or even of planets that are difficult to find.
ContributorsJacob, Samantha Renee (Author) / Bell Iii, James F (Thesis advisor) / Till, Christy B (Committee member) / Desch, Steven J (Committee member) / Robinson, Mark S (Committee member) / Williams, David A (Committee member) / Arizona State University (Publisher)
Created2022
Description
Water has shaped the surface of Mars, recording previous environments and inspiring the search for extinct life beyond Earth. While conditions on the Martian surface today are not conducive to the presence of liquid water, ancient erosional and depositional features indicate that this was not always so. Quantifying the regional and global history of water on Mars is crucial to understanding how the planet evolved, where to focus future exploration, and implications for water on Earth.
Many sites on Mars contain layered sedimentary deposits, sinuous valleys with delta shaped deposits, and other indications of large lakes. The Hypanis deposit is a unique endmember in this set of locations as it appears to be the largest ancient river delta identified on the planet, and it appears to have no topographic boundary, implying deposition into a sea. I have used a variety of high-resolution remote sensing techniques and geologic mapping techniques to present a new model of past water activity in the region.
I gathered new orbital observations and computed thermal inertia, albedo, elevation, and spectral properties of the Hypanis deposit. I measured the strike and dip of deposit layers to interpret the sedimentary history. My results indicate that Hypanis was formed in a large calm lacustrine setting. My geomorphic mapping of the deposit and catchment indicates buried volatile-rich sediments erupted through the Chryse basin fill, and may be geological young or ongoing. Collectively, my results complement previous studies that propose a global paleoshoreline, and support interpretations that Mars had an ocean early in its history. Future missions to the Martian surface should consider Hypanis as a high-value sampling opportunity.
Many sites on Mars contain layered sedimentary deposits, sinuous valleys with delta shaped deposits, and other indications of large lakes. The Hypanis deposit is a unique endmember in this set of locations as it appears to be the largest ancient river delta identified on the planet, and it appears to have no topographic boundary, implying deposition into a sea. I have used a variety of high-resolution remote sensing techniques and geologic mapping techniques to present a new model of past water activity in the region.
I gathered new orbital observations and computed thermal inertia, albedo, elevation, and spectral properties of the Hypanis deposit. I measured the strike and dip of deposit layers to interpret the sedimentary history. My results indicate that Hypanis was formed in a large calm lacustrine setting. My geomorphic mapping of the deposit and catchment indicates buried volatile-rich sediments erupted through the Chryse basin fill, and may be geological young or ongoing. Collectively, my results complement previous studies that propose a global paleoshoreline, and support interpretations that Mars had an ocean early in its history. Future missions to the Martian surface should consider Hypanis as a high-value sampling opportunity.
ContributorsAdler, Jacob (Author) / Bell, James (Thesis advisor) / Christensen, Philip R. (Philip Russel) (Committee member) / Robinson, Mark (Committee member) / Asphaug, Erik (Committee member) / Whipple, Kelin (Committee member) / Arizona State University (Publisher)
Created2019
Description
The presence of ices (H2O and CO2) and liquid water is key to the evolution ofmartian geology, with implications for the potential for past or extant life, and the future
of robotic and human exploration on Mars.
In this dissertation, I present the first direct evidence that the smooth deposits
covering mid-latitude, martian pole-facing slopes are composed of shallow dusty H2O ice
covered by desiccated material. To analyze this H2O ice, I developed the first validated
radiative transfer model for dusty martian snow and glacier ice. I found that these ice
exposures have < 1% dust in them, and discovered the lowest latitude detection of H2O
ice on Mars, at 32.9°S. After observing the ice disappear, and new gully channels form, I
proposed a model for gully formation. In this model, dusty ice gets exposed by slumping,
leading to melting in the subsurface and channels eroding within the ice and the wall rock
beneath. Access to liquid water within this ice could provide potential abodes for any
extant life.
Next, I developed novel methodology to search for CO2 frosts within the entire
Thermal Emission Imaging System (THEMIS) infrared dataset and found that about half
of all gullies overlap with CO2 frost detections. I also used the Thermal Emission
Spectrometer (TES) water vapor retrievals to assess the formation and distribution of
H2O frosts on Mars.
Additionally, I used radar data from the Mars Advanced Radar for Subsurface and
Ionospheric Sounding (MARSIS) instrument to investigate Mars’ ice-rich South Polar Layered Deposits (SPLD). I discovered radar signals similar to those proposed to be
caused by a subglacial lake throughout the martian SPLD.
Finally, I mapped martian polygonal ridge networks thought to represent
fossilized remnants of ancient groundwater near the Perseverance rover landing site with
the help of citizen scientists across a fifth of Mars’ total surface area and analyzed their
thermophysical properties.
All these studies highlight the key role that ices and liquid water have played in
shaping Mars’ landscape through time, and provide an intriguing path forward in martian
exploration and the search for alien life.
ContributorsKhuller, Aditya Rai (Author) / Christensen, Philip R (Thesis advisor) / Ruff, Steven W (Committee member) / Whipple, Kelin X (Committee member) / Sharp, Thomas G (Committee member) / Shim, Sang-Heon (Committee member) / Arizona State University (Publisher)
Created2023
Description
Identifying space resources is essential to establish an off-Earth human presence on the Moon, Mars, and beyond. One method for determining the composition and mineralogy of planetary surfaces is thermal infrared emission spectroscopy. I investigated this technique as a potential tool to explore for magmatic Ni-Cu±PGE sulfide deposits by producing and measuring a 100% sulfide (pyrrhotite) sample derived from the Stillwater Complex. Pyrrhotite violates key assumptions used to calibrate thermal infrared emission data, making extraterrestrial sulfides “appear colder” than their actual physical temperature, and their spectra will contain a negative slope. To derive the absolute emissivity of graybody minerals more accurately, I developed a new measurement technique, which demonstrates that pyrrhotite is spectrally featureless in the mid-infrared and has a maximum emissivity of ~0.7. Magmatic sulfide deposits are commonly associated with silicates. Thus, emissivity spectra of sulfide/silicate mixtures were acquired to further understand how sulfide prospecting would be conducted on rocky bodies such as Mars. I demonstrate that as sulfide increases, the apparent brightness temperature decreases linearly and, if left unaccounted for, will contribute a negative spectral slope in their emissivity spectra. The presence of sulfide also reduces the magnitude of all the silicate’s diagnostic spectral features, which is linear as sulfide increases. A linear retrieval algorithm was also applied to the mixture spectra, demonstrating that sulfide could be detected at abundances of ≥10 modal %.
The main resource being targeted for mining on the Moon is water ice. Thus, a mining map tool of the Lunar South Pole that incorporates temperature, illumination, Earth visibility, and slope data was developed to identify the most suitable locations for water ice mining and establishing bases for operations. The map is also used to assess the mining potential of the Artemis III candidate landing regions. Finally, space mining must be governed, but no framework has yet to be established. I propose a governance structure, notification system, contract system, best mining practices, and area-based environmental regulations to manage water ice mining activities. The Lunar Mining Map Tool’s block system is used as a spatial planning tool to administer the governance framework and facilitate management.
ContributorsHubbard, Kevin M (Author) / Elkins-Tanton, Linda T (Thesis advisor) / Christensen, Philip R (Committee member) / Semken, Steven (Committee member) / Sharp, Thomas (Committee member) / O'Rourke, Joseph G (Committee member) / De Zwart, Melissa (Committee member) / Arizona State University (Publisher)
Created2023
Description
Understanding the history of water on Mars is one of the highest priority goals of the international Mars exploration community. Water would have played a key role in any potential abiogenesis in the past and will play a key role in the future human exploration of the planet. Chloride salts are an indicator of past hydrologic activity in the Martian geologic record and have the potential to preserve fluid inclusions and organic material within their crystal structure over geologic timescales. This dissertation will describe an innovative method for identifying chloride salts on the Martian surface, explore the implication of their distribution within Early Noachian terrains, and document important opportunistic discoveries made in the process. Decorrelation stretched Thermal Emission Imaging System (THEMIS) infrared images have long been used to identify chloride salts on Mars, but the process has been time-consuming, subjective, and qualitative. By analyzing the entire THEMIS dataset, acquired over more than twenty years at Mars, a globally-applicable covariance matrix was calculated that describes the geologic diversity of the Martian surface. This covariance matrix allows all THEMIS daytime infrared images to be translated into globally-consistent decorrelation stretch and principal component images, enabling an automatic, objective, and quantitative method for identifying chloride salts. A new global survey located 1,605 chloride salt deposits across the Martian surface, a significant increase over previous surveys. In particular, the 257 deposits in Early Noachian terrains have characteristics that indicate they formed contemporaneously with the surrounding terrain. In addition, a chloride salt formation was identified on the floor of Ares Vallis with a unique three-dimensional structure that has been interpreted as an exposed chloride salt diapir, which would indicate the presence of a significant subsurface chloride salt layer. By improving our understanding of the distribution and diversity of chloride salts on the Martian surface, this work has provided future investigators with new tools and avenues of research to explore the history of water on Mars.
ContributorsHill, Jonathon Ryan (Author) / Christensen, Philip R. (Thesis advisor) / Sharp, Thomas G (Committee member) / Ruff, Steven W (Committee member) / Simon, Molly N (Committee member) / O'Rourke, Joseph G (Committee member) / Arizona State University (Publisher)
Created2022
Description
There are more than 20 active missions exploring planets and small bodies beyond Earth in our solar system today. Many more have completed their journeys or will soon begin. Each spacecraft has a suite of instruments and sensors that provide a treasure trove of data that scientists use to advance our understanding of the past, present, and future of the solar system and universe. As more missions come online and the volume of data increases, it becomes more difficult for scientists to analyze these complex data at the desired pace. There is a need for systems that can rapidly and intelligently extract information from planetary instrument datasets and prioritize the most promising, novel, or relevant observations for scientific analysis. Machine learning methods can serve this need in a variety of ways: by uncovering patterns or features of interest in large, complex datasets that are difficult for humans to analyze; by inspiring new hypotheses based on structure and patterns revealed in data; or by automating tedious or time-consuming tasks. In this dissertation, I present machine learning solutions to enhance the tactical planning process for the Mars Science Laboratory Curiosity rover and future tactically-planned missions, as well as the science analysis process for archived and ongoing orbital imaging investigations such as the High Resolution Imaging Science Experiment (HiRISE) at Mars. These include detecting novel geology in multispectral images and active nuclear spectroscopy data, analyzing the intrinsic variability in active nuclear spectroscopy data with respect to elemental geochemistry, automating tedious image review processes, and monitoring changes in surface features such as impact craters in orbital remote sensing images. Collectively, this dissertation shows how machine learning can be a powerful tool for facilitating scientific discovery during active exploration missions and in retrospective analysis of archived data.
ContributorsKerner, Hannah Rae (Author) / Bell, James F. (Thesis advisor) / Ben Amor, Heni (Thesis advisor) / Wagstaff, Kiri L (Committee member) / Hardgrove, Craig J (Committee member) / Shirzaei, Manoochehr (Committee member) / Arizona State University (Publisher)
Created2019
Description
In this thesis, I investigate possible formation processes in the northern Claritas Fossae and the large Thaumasia graben on Mars. In particular, I assess three proposed formation hypotheses for the region: a mega-landslide across the Thaumasia plateau, originating in Tharsis and moving to the south-west; a rift system pulling apart Claritas Fossae and opening the large Thaumasia graben generally propagating in a north-south direction: and extension caused by uplifting from underlying dike swarms. Using digital terrain models (DTMs) from the High Resolution Stereo Camera (HRSC) aboard Mars Express and visual images from the Context Camera (CTX) aboard the Mars Reconnaissance Orbiter (MRO), I analyzed the geomorphic and structural context of the region. Specifically, I produced geomorphologic and structural feature maps, conducted sector diagram analyses of fault propagation direction, calculated and compared extension and strain in local and regional samples, analyzed along strike throw-profiles of faults, and conducted surface age estimates through crater counting. I found that no single formation mechanism fully explains the surface features seen in Northern Claritas Fossae today. Instead I, propose the following sequence of events led to the surface characteristics we now observe. The region most likely underwent two episodes of uplift and extension due to sub-surface magmatic intrusions, then experienced an extensional event which produced the large Thaumasia graben. This was followed by the emplacement of a layer of lava burying the bottom of the Thaumasia graben and the eastern edge of the region. Additional extension followed across the eastern portion of the study area, and finally of a young lava flow was emplaced abutting and overprinting the southwestern edge.
ContributorsStuder-Ellis, Genevieve Lynn (Author) / Williams, David A. (Thesis advisor) / Christensen, Philip R. (Thesis advisor) / Arrowsmith, J. R. (Committee member) / Arizona State University (Publisher)
Created2019
Description
Part I – I analyze a database of Smoothed Particle Hydrodynamics (SPH) simulations of collisions between planetary bodies and use the data to define semi-empirical models that reproduce remant masses. These models may be leveraged when detailed, time-dependent aspects of the collision are not paramount, but analytical intuition or a rapid solution is required, e.g. in ‘N-body simulations’. I find that the stratification of the planet is a non-negligible control on accretion efficiency. I also show that the absolute scale (total mass) of the collision may affect the accretion efficiency, with larger bodies more efficiently disrupting, as a function of gravitational binding energy. This is potentially due to impact velocities above the sound speed. The interplay of these dependencies implies that planet formation, depending on the dynamical environment, may be separated into stages marked by differentiation and the growth of planets more massive than the Moon.
Part II – I examine time-resolved neutron data from the Dynamic Albedo of Neutrons (DAN) instrument on the Mars Science Laboratory (MSL) Curiosity rover. I personally and independently developed a data analysis routine (described in the supplementary material in Chapter 2) that utilizes spectra from Monte Carlo N-Particle Transport models of the experiment and the Markov-chain Monte Carlo method to estimate bulk soil/rock properties. The method also identifies cross-correlation and degeneracies. I use data from two measurement campaigns that I targeted during remote operations at ASU. I find that alteration zones of a sandstone unit in Gale crater are markedly elevated in H content from the parent rock, consistent with the presence of amorphous silica. I posit that these deposits were formed by the most recent aqueous alteration events in the crater, since subsequent events would have produced matured forms of silica that were not observed. I also find that active dunes in Gale crater contain minimal water and I developed a Monte Carlo phase analysis routine to understand the amorphous materials in the dunes.
Part II – I examine time-resolved neutron data from the Dynamic Albedo of Neutrons (DAN) instrument on the Mars Science Laboratory (MSL) Curiosity rover. I personally and independently developed a data analysis routine (described in the supplementary material in Chapter 2) that utilizes spectra from Monte Carlo N-Particle Transport models of the experiment and the Markov-chain Monte Carlo method to estimate bulk soil/rock properties. The method also identifies cross-correlation and degeneracies. I use data from two measurement campaigns that I targeted during remote operations at ASU. I find that alteration zones of a sandstone unit in Gale crater are markedly elevated in H content from the parent rock, consistent with the presence of amorphous silica. I posit that these deposits were formed by the most recent aqueous alteration events in the crater, since subsequent events would have produced matured forms of silica that were not observed. I also find that active dunes in Gale crater contain minimal water and I developed a Monte Carlo phase analysis routine to understand the amorphous materials in the dunes.
ContributorsGabriel, Travis Saint James (Author) / Asphaug, Erik I (Thesis advisor) / Hardgrove, Craig (Thesis advisor) / Sharp, Thomas (Committee member) / Zolotov, Mikhail (Committee member) / Young, Patrick (Committee member) / Arizona State University (Publisher)
Created2019