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You searched for subject:(surficial processes). Showing records 1 – 2 of 2 total matches.

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1. Mcgee, Benjamin Wright. Determining The Correlation Significance Between S-Type Asteroid Orbital Inclination And Albedo Attributable To Space Weathering.

Degree: MS, Space Studies, 2018, University of North Dakota

Recent research suggests that ion bombardment is more effective than micrometeoroid bombardment in albedo darkening of mature lunar soils, whereas micrometeoroid bombardment may act on longer timescales and is more effective in modifying the spectral features of a surface. This, in turn, may be extrapolated to suggest the following: 1) Increased intensities of ion bombardment would correlate negatively with the surface reflectivity of airless, silicate-bearing bodies known to express lunar-style space weathering, such as S-type asteroids, and 2) beyond that of sputtering and ion implantation, there is a gradient of potential interactions between the two weathering processes that may be relevant to space weathering at large, where via the processes of mineral metamictization and structural weakening, ion bombardment may act as a necessary precursor to micrometeroid bombardment in lunar-style space weathering. Because heliosphere research (i.e., the Ulysses spacecraft) reveals that the speed of solar wind rises with solar latitude from the equatorial plane to the poles, the possibility of a correlation is suggested between the albedo of a given S-type asteroid surface and its orbital inclination. In other words, more highly-inclined asteroids would be exposed to higher-intensity solar ion bombardment, which would thereby result in darker (or more quickly darkened) mature surfaces. This proposition is explored via the statistical analysis of a sample group of S-complex airless bodies, resulting in a statistically-significant negative correlation between orbital inclination and albedo at the 75% confidence level. An overall space-weathering scheme is proposed, and implications for space weathering mechanisms as they relate to orbital parameters are discussed. Advisors/Committee Members: Michael J. Gaffey.

Subjects/Keywords: airless bodies; asteroids; NEAs; space weather; space weathering; surficial processes

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Mcgee, B. W. (2018). Determining The Correlation Significance Between S-Type Asteroid Orbital Inclination And Albedo Attributable To Space Weathering. (Masters Thesis). University of North Dakota. Retrieved from https://commons.und.edu/theses/2283

Chicago Manual of Style (16th Edition):

Mcgee, Benjamin Wright. “Determining The Correlation Significance Between S-Type Asteroid Orbital Inclination And Albedo Attributable To Space Weathering.” 2018. Masters Thesis, University of North Dakota. Accessed March 29, 2020. https://commons.und.edu/theses/2283.

MLA Handbook (7th Edition):

Mcgee, Benjamin Wright. “Determining The Correlation Significance Between S-Type Asteroid Orbital Inclination And Albedo Attributable To Space Weathering.” 2018. Web. 29 Mar 2020.

Vancouver:

Mcgee BW. Determining The Correlation Significance Between S-Type Asteroid Orbital Inclination And Albedo Attributable To Space Weathering. [Internet] [Masters thesis]. University of North Dakota; 2018. [cited 2020 Mar 29]. Available from: https://commons.und.edu/theses/2283.

Council of Science Editors:

Mcgee BW. Determining The Correlation Significance Between S-Type Asteroid Orbital Inclination And Albedo Attributable To Space Weathering. [Masters Thesis]. University of North Dakota; 2018. Available from: https://commons.und.edu/theses/2283

2. Chojnacki, Matthew. Martian Dune Fields: Aeolian Activity, Morphology, Sediment Pathways, and Provenance.

Degree: 2013, University of Tennessee – Knoxville

Wind has likely been the dominant geologic agent for most of Mars’ history. The wide-spread nature of sand dunes there shows that near-surface winds have commonly interacted with plentiful mobile sediments. Early studies of these dunes suggested minimal activity, dominantly unidirectional simple dune morphologies, and little variations in basaltic sand compositions. This dissertation examines martian sand dunes and aeolian systems, in terms of their activity, morphologies, thermophysical properties, sand compositions, geologic contexts, and source-lithologies using new higher-resolution orbital data. Although previous evidence for contemporary dune activity has been limited, results presented in Chapter II show substantial activity in Endeavour Crater, Meridiani Planum. The translation and erosion of dunes there constitutes the largest contemporary movement of sand-sized sediment reported on Mars to date and demonstrates that Endeavour crater has been subject to wind profiles exceeding the threshold velocity at the surface (daily/seasonally and/or episodically) in the recent past. Global mapping has shown dune fields to dominantly occur in topographically benign locations (e.g., craters, polar basins), where the largest exception is the Valles Marineris (VM) rift system. Chapter III documents multiple occurrences of “wall dunes” found several kilometers above the canyon floor. These relatively unique dune morphologies show that wind blown sediment has interacted with local and regional topography and are relevant for understanding aeolian sediment flux, sediment sources, and wind directions. Chapter IV provides results of a low- to mid-latitude survey of all martian dune fields in comparison to the extensive dune population in VM to test the effect of local and regional environments on duneform properties. That study found VM dune fields to be qualitatively and quantitatively distinct from other dune populations, most readily attributed to the rift’s unusual setting. Sources and pathways of the martian sand have largely been uncertain. Chapter V documents likely sediment sources and pathways for the VM dune populations, where local and regional derivation of dune sand has occurred. We find in some chasmata dune sand is dominantly derived from Noachian-aged (altered and unaltered) igneous wall materials, whereas in other chasmata dunes are sourced from Early Hesperian-aged sulfate-bearing sedimentary layered deposits.

Subjects/Keywords: Mars; geology; surficial processes; aeolian systems; sand dunes; remote sensing; composition; Geology; Geomorphology; Physical Processes; Sedimentology; The Sun and the Solar System

…atmospheric chemistry. The potential discovery of dunes on Pluto would indicate aeolian processes… …aeolian systems provide clues to sedimentary processes, crustal compositions, alteration… …processes, and near-surface atmospheric flow. 2 I choose the topic of martian sand dunes for my… …importantly, these dust storms indicate aeolian sedimentary processes are active under 3… …reported. Although aeolian processes appear to be the dominant geologic process in Mars’ recent… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Chojnacki, M. (2013). Martian Dune Fields: Aeolian Activity, Morphology, Sediment Pathways, and Provenance. (Doctoral Dissertation). University of Tennessee – Knoxville. Retrieved from https://trace.tennessee.edu/utk_graddiss/1707

Chicago Manual of Style (16th Edition):

Chojnacki, Matthew. “Martian Dune Fields: Aeolian Activity, Morphology, Sediment Pathways, and Provenance.” 2013. Doctoral Dissertation, University of Tennessee – Knoxville. Accessed March 29, 2020. https://trace.tennessee.edu/utk_graddiss/1707.

MLA Handbook (7th Edition):

Chojnacki, Matthew. “Martian Dune Fields: Aeolian Activity, Morphology, Sediment Pathways, and Provenance.” 2013. Web. 29 Mar 2020.

Vancouver:

Chojnacki M. Martian Dune Fields: Aeolian Activity, Morphology, Sediment Pathways, and Provenance. [Internet] [Doctoral dissertation]. University of Tennessee – Knoxville; 2013. [cited 2020 Mar 29]. Available from: https://trace.tennessee.edu/utk_graddiss/1707.

Council of Science Editors:

Chojnacki M. Martian Dune Fields: Aeolian Activity, Morphology, Sediment Pathways, and Provenance. [Doctoral Dissertation]. University of Tennessee – Knoxville; 2013. Available from: https://trace.tennessee.edu/utk_graddiss/1707

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