Document Type
Thesis
Date of Degree Completion
Spring 2015
Degree Name
Master of Science (MS)
Department
Geological Sciences
Committee Chair
Wendy A. Bohrson
Second Committee Member
Chris Mattinson
Third Committee Member
Jeffrey Lee
Abstract
Since 1971, Mt. Etna, Europe’s largest and most active volcano, has exhibited increased eruption frequency and explosivity. Associated with this increased activity, researchers have documented higher abundances of alkali elements (K, Rb, Cs) as well as elevated 87Sr/86Sr in Etnean lavas. The source of this alkali-enrichment has been hotly debated, with end-member hypotheses involving mantle vs. crustal contributions. To further characterize the evolution of the subvolcanic magma storage and transport system, as well as the timing and source of alkali-enrichment, clinopyroxene from ten samples erupted between 1329 and 2004 was targeted for in situ textural, major element and Sr isotope analysis. Clinopyroxene disequilibrium textures paired with increased Mg# values imply recharge/mixing at work within a dynamic magmatic system. Calculated pressures also reveal a dominant crystallization zone between ~8.7 and 16.5 km within the volcano’s carbonate substratum. A select population of clinopyroxene exhibits increasing weight percent CaO and Mg# with decreasing pressure, providing new evidence for late-stage carbonate assimilation enhanced by magmatic recharge. Alkali-enrichment is thus likely a consequence of both magma recharge and crustal assimilation.
Recommended Citation
Nelson, Kaitlyn, "Timing and Source of Alkali Enrichment at Mt. Etna, Sicily: Constraints from Clinopyroxene Geobarometry and In Situ SR Isotope Data" (2015). All Master's Theses. 276.
https://digitalcommons.cwu.edu/etd/276
Electronic Appendix A—Clinopyroxene Back-Scattered Electron Images 1329 and 1566
Electronic Appendix A.Clinopyroxene Back-Scattered Electron Images_1669.1 and 1669.2.pdf (20180 kB)
Electronic Appendix A—Clinopyroxene Back-Scattered Electron Images 1669.1 and 1669.2
Electronic Appendix A.Clinopyroxene Back-Scattered Electron Images_1886 and 1964.pdf (51689 kB)
Electronic Appendix A—Clinopyroxene Back-Scattered Electron Images 1886 and 1964
Electronic Appendix A.Clinopyroxene Back-Scattered Electron Images_1981 and 2001.1.pdf (69736 kB)
Electronic Appendix A—Clinopyroxene Back-Scattered Electron Images 1981 and 2001.1
Electronic Appendix A.Clinopyroxene Back-Scattered Electron Images_2004.1.pdf (35703 kB)
Electronic Appendix A—Clinopyroxene Back-Scattered Electron Images 2004.1
Electronic Appendix B.Electron Probe Microanalysis Data.xlsx (195 kB)
Electronic Appendix B—Electron Probe Microanalysis Data
Electronic Appendix C.Full Petrographic Descriptions.docx (4522 kB)
Electronic Appendix C—Full Petrographic Descriptions
Electronic Appendix D. All In Situ Clinopyroxene Data.xlsx (601 kB)
Electronic Appendix D—All In Situ Clinopyroxene Data
Language
English
Comments
I will submit the embargo signature form as soon as possible. My advisor is currently out of the country, and thus, unable to complete her portion at this time. However, we have together decided upon a five-year embargo.