Oxygen isotope evidence for the origin of chemical variations in lavas from Theistareykir volcano in Iceland's northern volcanic zone
Oxygen isotope ratios in phenocrysts from recent Theistareykir lavas (Iceland) are consistently ^(18)O-depleted relative to common terrestrial basalts (e.g. δ^(18)O olivine=4.7–4.1‰) and correlate with geochemical indices of ‘enrichment’ (e.g. K_2O/TiO_2; La/Sm) and major element indices of differen...
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ftcaltechauth:oai:authors.library.caltech.edu:35036 2023-05-15T16:48:20+02:00 Oxygen isotope evidence for the origin of chemical variations in lavas from Theistareykir volcano in Iceland's northern volcanic zone Eiler, John M. Grönvold, Karl Kitchen, Nami 2000-12-30 https://authors.library.caltech.edu/35036/ https://resolver.caltech.edu/CaltechAUTHORS:20121023-112111281 unknown Elsevier Eiler, John M. and Grönvold, Karl and Kitchen, Nami (2000) Oxygen isotope evidence for the origin of chemical variations in lavas from Theistareykir volcano in Iceland's northern volcanic zone. Earth and Planetary Science Letters, 184 (1). pp. 269-286. ISSN 0012-821X. doi:10.1016/S0012-821X(00)00318-6. https://resolver.caltech.edu/CaltechAUTHORS:20121023-112111281 <https://resolver.caltech.edu/CaltechAUTHORS:20121023-112111281> Article PeerReviewed 2000 ftcaltechauth https://doi.org/10.1016/S0012-821X(00)00318-6 2021-11-11T18:51:40Z Oxygen isotope ratios in phenocrysts from recent Theistareykir lavas (Iceland) are consistently ^(18)O-depleted relative to common terrestrial basalts (e.g. δ^(18)O olivine=4.7–4.1‰) and correlate with geochemical indices of ‘enrichment’ (e.g. K_2O/TiO_2; La/Sm) and major element indices of differentiation (e.g. Mg#; CaO/Na_2O). The sense of these correlations is that decreasing δ^(18)O is accompanied by increasing ‘enriched’ geochemical signatures and an increasing extent of differentiation. These trends are similar to (although more subtle than) those defined by highly differentiated and contaminated Icelandic andesites, dacites and rhyolites. The trends we observe are consistent with models in which primary recent Theistareykir magmas are highly ‘depleted’ in their incompatible element geochemistry and similar in δ^(18)O to common terrestrial basalts; differentiation of these magmas is accompanied by contamination by the low δ^(18)O, and on average more ‘enriched’ rocks of the Icelandic crust to produce the observed spectrum in δ^(18)O and other geochemical indices. Our results suggest that geochemical variations among recent Theistareykir lavas are only indirect constraints on the composition and dynamics of the Iceland plume. Extrapolation of the geochemical trends we observe to oxygen isotope compositions within the range of common oceanic basalts suggests that primary recent Theistareykir magmas are exceptionally depleted (e.g. La/Sm=0.2–0.5), indicating unusually high degrees and/or multiple stages of melting of their sources. Article in Journal/Newspaper Iceland Caltech Authors (California Institute of Technology) Earth and Planetary Science Letters 184 1 269 286 |
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Caltech Authors (California Institute of Technology) |
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Oxygen isotope ratios in phenocrysts from recent Theistareykir lavas (Iceland) are consistently ^(18)O-depleted relative to common terrestrial basalts (e.g. δ^(18)O olivine=4.7–4.1‰) and correlate with geochemical indices of ‘enrichment’ (e.g. K_2O/TiO_2; La/Sm) and major element indices of differentiation (e.g. Mg#; CaO/Na_2O). The sense of these correlations is that decreasing δ^(18)O is accompanied by increasing ‘enriched’ geochemical signatures and an increasing extent of differentiation. These trends are similar to (although more subtle than) those defined by highly differentiated and contaminated Icelandic andesites, dacites and rhyolites. The trends we observe are consistent with models in which primary recent Theistareykir magmas are highly ‘depleted’ in their incompatible element geochemistry and similar in δ^(18)O to common terrestrial basalts; differentiation of these magmas is accompanied by contamination by the low δ^(18)O, and on average more ‘enriched’ rocks of the Icelandic crust to produce the observed spectrum in δ^(18)O and other geochemical indices. Our results suggest that geochemical variations among recent Theistareykir lavas are only indirect constraints on the composition and dynamics of the Iceland plume. Extrapolation of the geochemical trends we observe to oxygen isotope compositions within the range of common oceanic basalts suggests that primary recent Theistareykir magmas are exceptionally depleted (e.g. La/Sm=0.2–0.5), indicating unusually high degrees and/or multiple stages of melting of their sources. |
format |
Article in Journal/Newspaper |
author |
Eiler, John M. Grönvold, Karl Kitchen, Nami |
spellingShingle |
Eiler, John M. Grönvold, Karl Kitchen, Nami Oxygen isotope evidence for the origin of chemical variations in lavas from Theistareykir volcano in Iceland's northern volcanic zone |
author_facet |
Eiler, John M. Grönvold, Karl Kitchen, Nami |
author_sort |
Eiler, John M. |
title |
Oxygen isotope evidence for the origin of chemical variations in lavas from Theistareykir volcano in Iceland's northern volcanic zone |
title_short |
Oxygen isotope evidence for the origin of chemical variations in lavas from Theistareykir volcano in Iceland's northern volcanic zone |
title_full |
Oxygen isotope evidence for the origin of chemical variations in lavas from Theistareykir volcano in Iceland's northern volcanic zone |
title_fullStr |
Oxygen isotope evidence for the origin of chemical variations in lavas from Theistareykir volcano in Iceland's northern volcanic zone |
title_full_unstemmed |
Oxygen isotope evidence for the origin of chemical variations in lavas from Theistareykir volcano in Iceland's northern volcanic zone |
title_sort |
oxygen isotope evidence for the origin of chemical variations in lavas from theistareykir volcano in iceland's northern volcanic zone |
publisher |
Elsevier |
publishDate |
2000 |
url |
https://authors.library.caltech.edu/35036/ https://resolver.caltech.edu/CaltechAUTHORS:20121023-112111281 |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
Eiler, John M. and Grönvold, Karl and Kitchen, Nami (2000) Oxygen isotope evidence for the origin of chemical variations in lavas from Theistareykir volcano in Iceland's northern volcanic zone. Earth and Planetary Science Letters, 184 (1). pp. 269-286. ISSN 0012-821X. doi:10.1016/S0012-821X(00)00318-6. https://resolver.caltech.edu/CaltechAUTHORS:20121023-112111281 <https://resolver.caltech.edu/CaltechAUTHORS:20121023-112111281> |
op_doi |
https://doi.org/10.1016/S0012-821X(00)00318-6 |
container_title |
Earth and Planetary Science Letters |
container_volume |
184 |
container_issue |
1 |
container_start_page |
269 |
op_container_end_page |
286 |
_version_ |
1766038434015608832 |