Show simple item record

dc.contributor.advisorChemtob, Steven M.
dc.creatorAraneda Noboa, Paula
dc.date.accessioned2021-08-23T18:17:51Z
dc.date.available2021-08-23T18:17:51Z
dc.date.issued2021
dc.identifier.urihttp://hdl.handle.net/20.500.12613/6890
dc.description.abstractPhyllosilicates are widespread on Noachian to Early Hesperian terrains on Mars and can help constrain the planet’s geologic and environmental history, particularly its aqueous and redox history, which in turn can provide clues about past habitability. A range of ferrous and mixed-valence smectites were synthesized and then exposed to varying O2 fluxes under dry conditions to determine if Fe/Mg trioctahedral smectites can be oxidized without an aqueous medium to form dioctahedral smectites like those observed on the surface of Mars. The appearance of a secondary peak in some unaltered samples indicates a separate phase formed during synthesis, which remained throughout the oxidation process. Partial oxidation was achieved by all samples, but only those with the highest starting Fe3+ content reached almost complete oxidation. Rapid initial oxidation was observed for all samples, but seemed to subside before oxidation was complete, indicating the process becomes unfavorable after a certain point. All three O2 fluxes used in this study were successful in partially oxidizing the smectite samples but no correlation was observed between O2 flux and actual amount of oxidation, i.e., a higher O2 flux does not necessarily result in higher production of ferric iron. The process of oxidation did cause octahedral sheet contraction in some cases; however, in some samples octahedral sheet expansion was observed with oxidation. No additional phases were formed upon oxidation and no Fe ejection was observed. Overall, the amount of oxidation observed for all samples indicates that O2 alteration of trioctahedral smectites into dioctahedral smectites can proceed under dry conditions, meaning oxidation could have continued on Mars after surface water dried up.
dc.format.extent100 pages
dc.language.isoeng
dc.publisherTemple University. Libraries
dc.relation.ispartofTheses and Dissertations
dc.rightsIN COPYRIGHT- This Rights Statement can be used for an Item that is in copyright. Using this statement implies that the organization making this Item available has determined that the Item is in copyright and either is the rights-holder, has obtained permission from the rights-holder(s) to make their Work(s) available, or makes the Item available under an exception or limitation to copyright (including Fair Use) that entitles it to make the Item available.
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectGeochemistry
dc.subjectMineralogy
dc.subjectGeology
dc.subjectClay minerals
dc.subjectFe/Mg smectites
dc.subjectMartian geochemistry
dc.subjectMartian mineralogy
dc.subjectPlanetary geology
dc.subjectSmectites
dc.titleDry Oxidation of Ferrous and Mixed-valence Smectites and Its Implications for the Oxidative History of Mars
dc.typeText
dc.type.genreThesis/Dissertation
dc.contributor.committeememberDavatzes, Alexandra K.
dc.contributor.committeememberKim, Bojeong
dc.description.departmentGeology
dc.relation.doihttp://dx.doi.org/10.34944/dspace/6872
dc.ada.noteFor Americans with Disabilities Act (ADA) accommodation, including help with reading this content, please contact scholarshare@temple.edu
dc.description.degreeM.S.
dc.identifier.proqst14632
dc.creator.orcid0000-0002-7727-0231
dc.date.updated2021-08-21T10:09:10Z
refterms.dateFOA2021-08-23T18:17:51Z
dc.identifier.filenameAranedaNoboa_temple_0225M_14632.pdf


Files in this item

Thumbnail
Name:
AranedaNoboa_temple_0225M_14632.pdf
Size:
3.284Mb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record