{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/78756"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/78756","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Sound velocity study of natural orthopyroxenes with varying iron content","abstract":"Determination of the acoustic wave velocities of orthopyroxene as a function of composition is essential to identify the underlying causes of seismic heterogeneity. Such laboratory measurements are essential to determine the structure, composition and temperature variability of the upper mantle. This study presents a systematic characterization of orthopyroxene elastic moduli as a function of composition in the enstatite-orthoferrosilite system. For each sample and composition, the sound velocities are measured by Brillouin scattering in three orthogonal crystallographic planes. Inverting sound velocity data allows determination of the complete elastic modulus tensor, as well as the adiabatic bulk (Ks) and shear (μs) moduli. Samples were naturally occurring with approximate compositions: En90, En79, En74, and En55. The results establish nearly linear trends of VP and VS as a function of mole fraction En between the end members enstatite (Jackson et al 2007) and orthoferrosilite (Bass and Weidner 1984). Analysis of previous studies on orthopyroxene and the present work confirms that aluminum has the effects of increasing Ks while also confirming no discernable effect from Ca substitution. Ks. is poorly correlated to Mg-Fe substitution whereas μs correlates in a more linear between the end-members. These findings will help better characterize chemical, namely Mg and Fe, heterogeneity in the upper mantle.","abstract_html":"Determination of the acoustic wave velocities of orthopyroxene as a function of composition is essential to identify the underlying causes of seismic heterogeneity. Such laboratory measurements are essential to determine the structure, composition and temperature variability of the upper mantle. This study presents a systematic characterization of orthopyroxene elastic moduli as a function of composition in the enstatite-orthoferrosilite system. For each sample and composition, the sound velocities are measured by Brillouin scattering in three orthogonal crystallographic planes. Inverting sound velocity data allows determination of the complete elastic modulus tensor, as well as the adiabatic bulk (Ks) and shear (μs) moduli. Samples were naturally occurring with approximate compositions: En90, En79, En74, and En55. The results establish nearly linear trends of VP and VS as a function of mole fraction En between the end members enstatite (Jackson et al 2007) and orthoferrosilite (Bass and Weidner 1984). Analysis of previous studies on orthopyroxene and the present work confirms that aluminum has the effects of increasing Ks while also confirming no discernable effect from Ca substitution. Ks. is poorly correlated to Mg-Fe substitution whereas μs correlates in a more linear between the end-members. These findings will help better characterize chemical, namely Mg and Fe, heterogeneity in the upper mantle.","abstract_has_math":false,"creators":["Picek, Stephen M"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Geology","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-07-22T22:45:36Z","date_published":"2015-07-22T22:45:36Z","updated_at":"2026-07-22T22:26:12Z","subjects":["orthopyroxene","elasticity","Brillouin scattering","upper mantle heterogeneity"],"languages":["en"],"rights":["Copyright 2015 Stephen Picek"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/78756","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Picek, Stephen M"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-07-22T22:45:36Z","2017-07-23T09:15:27Z","2015-05","2015-04-21","2015-5"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Geology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["orthopyroxene","elasticity","Brillouin scattering","upper mantle heterogeneity"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2015 Stephen Picek"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/78756"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Determination of the acoustic wave velocities of orthopyroxene as a function of composition is essential to identify the underlying causes of seismic heterogeneity. Such laboratory measurements are essential to determine the structure, composition and temperature variability of the upper mantle. This study presents a systematic characterization of orthopyroxene elastic moduli as a function of composition in the enstatite-orthoferrosilite system. For each sample and composition, the sound velocities are measured by Brillouin scattering in three orthogonal crystallographic planes. Inverting sound velocity data allows determination of the complete elastic modulus tensor, as well as the adiabatic bulk (Ks) and shear (μs) moduli. Samples were naturally occurring with approximate compositions: En90, En79, En74, and En55. The results establish nearly linear trends of VP and VS as a function of mole fraction En between the end members enstatite (Jackson et al 2007) and orthoferrosilite (Bass and Weidner 1984). Analysis of previous studies on orthopyroxene and the present work confirms that aluminum has the effects of increasing Ks while also confirming no discernable effect from Ca substitution. Ks. is poorly correlated to Mg-Fe substitution whereas μs correlates in a more linear between the end-members. These findings will help better characterize chemical, namely Mg and Fe, heterogeneity in the upper mantle.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2017-05-01","The student, Stephen Picek, accepted the attached license on 2015-04-20 at 15:16.","The student, Stephen Picek, submitted this Thesis for approval on 2015-04-20 at 15:22.","This Thesis was approved for publication on 2015-04-21 at 11:18.","DSpace SAF Submission Ingestion Package generated from Vireo submission #7957 on 2015-07-22 at 14:25:32","Made available in DSpace on 2015-07-22T22:45:36Z (GMT). No. of bitstreams: 2 PICEK-THESIS-2015.pdf: 3627759 bytes, checksum: 12133a66c9c232895b8e3bf8d84a6369 (MD5) LICENSE.txt: 4210 bytes, checksum: 2c5a4d2cfcf89016a992ed812f7a736f (MD5) Previous issue date: 2015-04-21","Embargo set by: Seth Robbins for item 79997 Lift date: 2017-07-22T22:46:21Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 79997 on 2017-07-23T09:15:27Z."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Sound velocity study of natural orthopyroxenes with varying iron content"]}]}],"canonical_facts":{"dc:creator":["Picek, Stephen M"],"dc:date":["2015-07-22T22:45:36Z","2017-07-23T09:15:27Z","2015-05","2015-04-21","2015-5"],"dc:description":["Determination of the acoustic wave velocities of orthopyroxene as a function of composition is essential to identify the underlying causes of seismic heterogeneity. Such laboratory measurements are essential to determine the structure, composition and temperature variability of the upper mantle. This study presents a systematic characterization of orthopyroxene elastic moduli as a function of composition in the enstatite-orthoferrosilite system. For each sample and composition, the sound velocities are measured by Brillouin scattering in three orthogonal crystallographic planes. Inverting sound velocity data allows determination of the complete elastic modulus tensor, as well as the adiabatic bulk (Ks) and shear (μs) moduli. Samples were naturally occurring with approximate compositions: En90, En79, En74, and En55. The results establish nearly linear trends of VP and VS as a function of mole fraction En between the end members enstatite (Jackson et al 2007) and orthoferrosilite (Bass and Weidner 1984). Analysis of previous studies on orthopyroxene and the present work confirms that aluminum has the effects of increasing Ks while also confirming no discernable effect from Ca substitution. Ks. is poorly correlated to Mg-Fe substitution whereas μs correlates in a more linear between the end-members. These findings will help better characterize chemical, namely Mg and Fe, heterogeneity in the upper mantle.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2017-05-01","The student, Stephen Picek, accepted the attached license on 2015-04-20 at 15:16.","The student, Stephen Picek, submitted this Thesis for approval on 2015-04-20 at 15:22.","This Thesis was approved for publication on 2015-04-21 at 11:18.","DSpace SAF Submission Ingestion Package generated from Vireo submission #7957 on 2015-07-22 at 14:25:32","Made available in DSpace on 2015-07-22T22:45:36Z (GMT). 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