The effects of composition, pressure and oxygen fugacity on partition coefficients between amphibole and hydrous basaltic melt were studied at 1.5 to 2.5 GPa and 1000 to 1130°C. Partition coefficients (D i = concentration of element i in amphibole/concentration of i in melt) of large-ion-lithophile elements (LILE: Rb, Sr, Ba), high-field-strength elements (HFSE: Y, Zr, Nb, Ta, Hf), and rare-earth elements (REE: La to Lu) were determined between amphiboles and coexisting quenched melts created by partial crystallization of seven different starting compositions in a piston-cylinder high-pressure apparatus. Trace elements were analyzed by laser-ablation, microprobe inductively coupled plasma-mass spectrometer (LAM-ICP-MS). The effects of premium, temperature and oxygen fugacity on the partition coefficients are minor, but statistically measurable. Amphibole composition affects partitioning of these trace elements by a maximum factor of 3.5 in the range of pressures and temperatures studied with an oxygen fugacity range of 2 orders of magnitude above and below nickel-nickel oxide buffer. Experiments specifically investigating the role of Ti demonstrate that a positive correlation exists between amphibole VITi 4+ content and DBa, D Sr, DTa, D Zr, DLa, DCe, DPr, and DNd. Increasing pressure from 1.5 GPa, to 2.2 or 2.5 GPa (depending upon composition) increases DLILE, but decreases DHFSE and DREE. Raising the oxygen fugacity at 1.5 or 2.5 GPa by 3 orders of magnitude increases DRb, DBa, DLa, and D Nd, whereas DTi, D Hf, and DZr decrease; however, the maximum difference between partition coefficients measured at low and high oxygen fugacities is only a factor of 1.7. All of the effects of composition, pressure, and oxygen fugacity reflect the control of crystal chemistry on the partitioning of trace elements between amphibole and basaltic melt. No effects of melt composition were discerned in this study. The measured partition coefficients were used to investigate tr
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.34939 |
| Date | January 1997 |
| Creators | Dalpé, Claude. |
| Contributors | Baker, Don R. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Earth and Planetary Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001610423, proquestno: NQ44399, Theses scanned by UMI/ProQuest. |
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