Electrochemical measurements bearing on the oxidation state of the Skaergaard Layered Intrusion
dc.contributor.author | Arculus, Richard J. | en_US |
dc.contributor.author | Delano, John W. | en_US |
dc.contributor.author | Loureiro, Daniel | en_US |
dc.contributor.author | Kersting, Annie B. | en_US |
dc.date.accessioned | 2006-09-11T18:48:12Z | |
dc.date.available | 2006-09-11T18:48:12Z | |
dc.date.issued | 1989-07 | en_US |
dc.identifier.citation | Kersting, Annie B.; Arculus, Richard J.; Delano, John W.; Loureiro, Daniel; (1989). "Electrochemical measurements bearing on the oxidation state of the Skaergaard Layered Intrusion." Contributions to Mineralogy and Petrology 102(3): 376-388. <http://hdl.handle.net/2027.42/47287> | en_US |
dc.identifier.issn | 1432-0967 | en_US |
dc.identifier.issn | 0010-7999 | en_US |
dc.identifier.uri | https://hdl.handle.net/2027.42/47287 | |
dc.description.abstract | The oxygen fugacities (fO 2 's) of magnetically-concentrated fractions (MCF) of three rock samples from the Skaergaard Layered Intrusion were measured between 800–1150° C using oxygen-specific, solid zirconia electrolytes at atmospheric pressure. Two of the bulk rock samples (an oxide cumulate and an oxide-bearing gabbro) are from the Middle Zone (MZ) and the other (an olivine plagioclase orthocumulate) is from the Lower Zone (LZ). All MCF define fO 2 versus T arrays that lie 1.5–0.5 log units above the fayalite-magnetite-quartz (FMQ) buffer. Experiments with different cell-imposed initial redox states (one from a reduced direction and one from an oxidized direction) were run on each sample in an attempt to achieve experimental reversibility. This was accomplished by imposing a known redox memory on the galvanic cell prior to loading each sample. Reversibility for each sample agreed to better than 0.2 of a log unit. Irreversible autoreduction of 0.2 of a log unit was observed on the two MZ samples at temperatures exceeding 1065° C. Scanning electron microscope and electron microprobe study of pre- and post-run products shows that reaction and textural re-equilibration occurred among the oxide phase assemblages under the experimental conditions employed. Careful characterization of pre- and post-run assemblages is clearly necessary before adequate interpretation of the experimental results can be made in these types of electrochemical studies. Different approaches to investigations of the fO 2 of the Skaergaard Intrusion, be it thermodynamic calculations or experimental methods, should yield concordant results or at least understandable discrepancies. Calculated fO 2 's using thermobarometry applied to the ilmenite-magnetite pairs in the post-experimental assemblages agree with the experimentally determined fO 2 's to within one log unit at a given temperature. These results are also consistent with previously calculated fO 2 values (Buddington and Lindsley 1964; Morse et al. 1980), but are considerably more oxidized than a previous electrolyte-based fO 2 study of a different sample suite from the Skaergaard (Sato and Valenza 1980) that include values close to the iron-wustite (IW) buffer from both MZ and LZ oxide separates. Differences between this electrochemical study and that of Sato and Valenza (1980) may be due to variations in the level of indigenous (or curatorially-introduced) carbon in the samples studied. Despite a number of experimental difficulties, electrochemical cells can provide an accurate and precise method of determining the oxygen fugacity of naturally occurring, complex oxide assemblages. Tight experimental reversals and reproducible values obtained in heating and cooling cycles are an indication of the precision and accuracy of the data recoverable with electrochemical cells. | en_US |
dc.format.extent | 2160157 bytes | |
dc.format.extent | 3115 bytes | |
dc.format.mimetype | application/pdf | |
dc.format.mimetype | text/plain | |
dc.language.iso | en_US | |
dc.publisher | Springer-Verlag | en_US |
dc.subject.other | Mineralogy | en_US |
dc.subject.other | Mineral Resources | en_US |
dc.subject.other | Geosciences | en_US |
dc.subject.other | Geology | en_US |
dc.title | Electrochemical measurements bearing on the oxidation state of the Skaergaard Layered Intrusion | en_US |
dc.type | Article | en_US |
dc.subject.hlbsecondlevel | Geology and Earth Sciences | en_US |
dc.subject.hlbsecondlevel | Chemistry | en_US |
dc.subject.hlbtoplevel | Science | en_US |
dc.description.peerreviewed | Peer Reviewed | en_US |
dc.contributor.affiliationum | Department of Geological Sciences, University of Michigan, 48109, Ann Arbor, MI, USA | en_US |
dc.contributor.affiliationum | Department of Geological Sciences, University of Michigan, 48109, Ann Arbor, MI, USA | en_US |
dc.contributor.affiliationother | Escuela de Geologia, Minas y Geofisica Facultad de Ingenieria Universidad Central de Venezuela Caracas, Venezuela | en_US |
dc.contributor.affiliationother | Department of Earth Sciences, State University of New York at Albany, 12222, Albany, NY, USA | en_US |
dc.contributor.affiliationumcampus | Ann Arbor | en_US |
dc.description.bitstreamurl | http://deepblue.lib.umich.edu/bitstream/2027.42/47287/1/410_2004_Article_BF00373730.pdf | en_US |
dc.identifier.doi | http://dx.doi.org/10.1007/BF00373730 | en_US |
dc.identifier.source | Contributions to Mineralogy and Petrology | en_US |
dc.owningcollname | Interdisciplinary and Peer-Reviewed |
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