The Elastic Behavior of Plagioclase Feldspar at High Pressure

Simple item page
dc.contributor.authorJohnson, Eledaen
dc.contributor.committeechairAngel, Ross J.en
dc.contributor.committeememberRoss, Nancy L.en
dc.contributor.committeememberCarpenter, Michaelen
dc.contributor.departmentGeosciencesen
dc.date.accessioned2014-03-14T20:50:48Zen
dc.date.adate2008-01-21en
dc.date.available2014-03-14T20:50:48Zen
dc.date.issued2007-12-07en
dc.date.rdate2008-01-21en
dc.date.sdate2007-12-26en
dc.description.abstractFeldspars are one of the archetypical families of framework silicates. They not only comprise around 60% volumetrically of the Earth's crust, but are among some of the most structurally complicated minerals. Investigation into the structural behavior of various intermediate plagioclases at pressure has been undertaken with the intent of categorizing the elastic behavior with pressure across the solid solution series and establishing a conceptual model to characterize feldspar compression. Complex behavior has been observed in the Equation of State for plagioclase feldspars in excess of 3 GPa, including an anomalous softening of ordered albite in excess of 8.4 GPa (Benusa et al 2005: Am Min 90:1115-1120). This softening was not observed in the EoS for the more intermediate plagioclase compositions containing between 20 and 40 mol% of end-member anorthite. The calculated elastic compliance tensor sums at room pressure show a general stiffening with increasing anorthite component, small elastic changes at the C-1 to I-1 transition, and a dominantly first-order response at the P-1 to I-1 transition near end-member anorthite. The crystal structure of An37 plagioclase was determined by single-crystal X-ray diffraction. The compression mechanisms in An37 are similar to those in albite at lower pressures. The softening in albite at higher pressures is therefore attributed to the structural shearing in albite that is absent in An37 plagioclase up to 9.5 GPa.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-12262007-110244en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12262007-110244/en
dc.identifier.urihttp://hdl.handle.net/10919/36450en
dc.publisherVirginia Techen
dc.relation.haspartejohnson_thesis.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectunit-cell parametersen
dc.subjectX-ray diffractionen
dc.subjectbulk modulusen
dc.subjectequation of stateen
dc.subjectelasticityen
dc.subjectplagioclaseen
dc.subjectpressureen
dc.titleThe Elastic Behavior of Plagioclase Feldspar at High Pressureen
dc.typeThesisen
thesis.degree.disciplineGeosciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
ejohnson_thesis.pdf
Size:
3.04 MB
Format:
Adobe Portable Document Format
Download

Collections

Masters Theses