The geochemistry of western Aleutian seafloor volcanoes indicates that primitive dacitic lavas (63-71% SiO2, Mg/Mg+Fe > 0.65) containing low abundances of middle and heavy rare-earth elements (Yb) were probably produced by melting of an isotopically MORB-like (e.g., 87Sr/86Sr < 0.7027) pyroxenite or subducted basaltic source. Andesites and dacites from emergent volcanoes throughout the Aleutians often also have low abundances of middle and heavy rare-earth elements (REE's), but these characteristics are widely attributed to fractional crystallization and the removal of amphibole from mafic melts in crustal magma chambers. For this study, geochemical data were collected for 50 lavas from Buldir Volcano, the westernmost emergent volcano in the Aleutian island arc, to investigate the role of amphibole fractionation versus source variability in the genesis of andesites and dacites from Buldir. Buldir lavas range from basalt to dacite and define a strongly calc-alkaline or low-Fe igneous series. Andesites and dacites at Buldir have low abundances of middle and heavy REE's (
","abstract_html":"<p>The geochemistry of western Aleutian seafloor volcanoes indicates that primitive dacitic lavas (63-71% SiO2, Mg/Mg+Fe > 0.65) containing low abundances of middle and heavy rare-earth elements (Yb) were probably produced by melting of an isotopically MORB-like (e.g., 87Sr/86Sr < 0.7027) pyroxenite or subducted basaltic source. Andesites and dacites from emergent volcanoes throughout the Aleutians often also have low abundances of middle and heavy rare-earth elements (REE's), but these characteristics are widely attributed to fractional crystallization and the removal of amphibole from mafic melts in crustal magma chambers. For this study, geochemical data were collected for 50 lavas from Buldir Volcano, the westernmost emergent volcano in the Aleutian island arc, to investigate the role of amphibole fractionation versus source variability in the genesis of andesites and dacites from Buldir. Buldir lavas range from basalt to dacite and define a strongly calc-alkaline or low-Fe igneous series. Andesites and dacites at Buldir have low abundances of middle and heavy REE's (</p>","abstract_has_math":false,"creators":["Arndt, Shawn"],"institution":null,"degree_name":"M.S.","degree_level":"Campus Access Thesis","degree_discipline":"Earth and Ocean Sciences","degree_department":null,"school":null,"contributors":["Gene M Yogodzinski"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-01-01T08:00:00Z","date_published":"2011-01-01T08:00:00Z","updated_at":"2026-07-24T04:37:56Z","subjects":["Earth Sciences","Geology","Physical Sciences and Mathematics","Aleutians","Amphibole","Buldir","Mixing","Volcano","Water"],"languages":[],"rights":["© 2011, Shawn Arndt"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarcommons.sc.edu/etd/1318","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Gene M Yogodzinski"]},{"key":"dc:creator","label":"Author","values":["Arndt, Shawn"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_discipline","label":"Discipline","values":["Earth and Ocean Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Campus Access Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Earth Sciences","Geology","Physical Sciences and Mathematics","Aleutians","Amphibole","Buldir","Mixing","Volcano","Water"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["© 2011, Shawn Arndt"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarcommons.sc.edu/etd/1318"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The geochemistry of western Aleutian seafloor volcanoes indicates that primitive dacitic lavas (63-71% SiO2, Mg/Mg+Fe > 0.65) containing low abundances of middle and heavy rare-earth elements (Yb) were probably produced by melting of an isotopically MORB-like (e.g., 87Sr/86Sr < 0.7027) pyroxenite or subducted basaltic source. Andesites and dacites from emergent volcanoes throughout the Aleutians often also have low abundances of middle and heavy rare-earth elements (REE's), but these characteristics are widely attributed to fractional crystallization and the removal of amphibole from mafic melts in crustal magma chambers. For this study, geochemical data were collected for 50 lavas from Buldir Volcano, the westernmost emergent volcano in the Aleutian island arc, to investigate the role of amphibole fractionation versus source variability in the genesis of andesites and dacites from Buldir. Buldir lavas range from basalt to dacite and define a strongly calc-alkaline or low-Fe igneous series. Andesites and dacites at Buldir have low abundances of middle and heavy REE's (
"]},{"key":"dc:title","label":"Title","values":["Controls of Melt Genesis and Evolution at Buldir Volcano in the Western Aleutian Island Arc"]}]}],"canonical_facts":{"dc:contributor":["Gene M Yogodzinski"],"dc:creator":["Arndt, Shawn"],"dc:description.abstract":["The geochemistry of western Aleutian seafloor volcanoes indicates that primitive dacitic lavas (63-71% SiO2, Mg/Mg+Fe > 0.65) containing low abundances of middle and heavy rare-earth elements (Yb) were probably produced by melting of an isotopically MORB-like (e.g., 87Sr/86Sr < 0.7027) pyroxenite or subducted basaltic source. Andesites and dacites from emergent volcanoes throughout the Aleutians often also have low abundances of middle and heavy rare-earth elements (REE's), but these characteristics are widely attributed to fractional crystallization and the removal of amphibole from mafic melts in crustal magma chambers. For this study, geochemical data were collected for 50 lavas from Buldir Volcano, the westernmost emergent volcano in the Aleutian island arc, to investigate the role of amphibole fractionation versus source variability in the genesis of andesites and dacites from Buldir. Buldir lavas range from basalt to dacite and define a strongly calc-alkaline or low-Fe igneous series. Andesites and dacites at Buldir have low abundances of middle and heavy REE's (
"],"dc:identifier":["https://scholarcommons.sc.edu/etd/1318"],"dc:rights":["© 2011, Shawn Arndt"],"dc:subject":["Earth Sciences","Geology","Physical Sciences and Mathematics","Aleutians","Amphibole","Buldir","Mixing","Volcano","Water"],"dc:title":["Controls of Melt Genesis and Evolution at Buldir Volcano in the Western Aleutian Island Arc"],"thesis:degree_discipline":["Earth and Ocean Sciences"],"thesis:degree_level":["Campus Access Thesis"],"thesis:degree_name":["M.S."]},"updated_at":"2026-07-24T04:37:56Z"}