First Advisor

Martin J. Streck

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Geology




Igneous rocks -- Oregon -- Mount Hood Wilderness, Lava -- Oregon -- Mount Hood Wilderness, Andesite -- Oregon -- Mount Hood Wilderness



Physical Description

1 online resource (183 p.)


Throughout its eruptive history, Mount Hood has produced compositionally similar calc-alkaline andesite as lava flows and domes near the summit and basaltic andesitic flows from flank vents. Found within the andesite are slightly more mafic inclusions that are compositionally similar to the host andesite (or host lavas); no inclusions were found in the flank lavas. Host lavas and inclusions have the following mineral assemblage: plag + opx ± cpx ± amp + oxides. Flank lava mineralogy is similar to the inclusions and host lavas, but since they are more mafic they contain olivine instead of amphibole. Average silica content among samples analyzed ranges from 57.6 to 62.7 weight percent; however the incompatible trace element composition is more variable at lower silica contents and becomes less variable at higher silica contents. In terms of incompatible trace element composition, the host lavas and inclusions are either depleted (no amp) or enriched (amp± cpx).


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Persistent Identifier

Appendix G-AFC Process.doc (17 kB)
Appendix G-AFC Process

Appendix G-AFC Model FL-HL.xls (1639 kB)
Appendix G-AFC Model FL-HL

Appendix G-AFC Model FL-HSEM.xls (286 kB)
Appendix G-AFC Model FL-HSEM

Appendix G-AFC Model HMEM-HL.xls (1747 kB)
Appendix G-AFC Model HMEM-HL

Appendix G-AFC Model HMEM-HSEM.xls (1644 kB)
Appendix G-AFC Model HMEM-HSEM

Appendix G-AFC Model HMEM-INCL.xls (1652 kB)
Appendix G-AFC Model HMEM-INCL

Appendix G-AFC Model INCL-HL.xls (832 kB)
Appendix G-AFC Model INCL-HL

Appendix G-AFC Model INCL-HSEM.xls (830 kB)
Appendix G-AFC Model INCL-HSEM

Appendix H-Microprobe.doc (55 kB)
Appendix H-Microprobe

Appendix H-Amphibole Analysis.xls (395 kB)
Appendix H-Amphibole Analysis

Appendix H-Plagioclase Analysis.xls (619 kB)
Appendix H-Plagioclase Analysis

Appendix H-Pyroxene Analysis.xls (317 kB)
Appendix H-Pyroxene Analysis