Geothermometry using minor and trace elements in igneous and hydrothermal magnetite
| dc.contributor.author | Canil, Dante | |
| dc.contributor.author | Lacourse, Terri | |
| dc.date.accessioned | 2021-07-14T18:30:40Z | |
| dc.date.copyright | 2020 | en_US |
| dc.date.issued | 2020 | |
| dc.description.abstract | The temperature (T) and oxygen fugacity (fO2) dependence of minor and trace elements (Mg, Al, Mn, Cr, Ni) in magnetite (Mag) in equilibrium with water-bearing silicate liquids varying in composition from basalt to rhyolite (49–77 wt% SiO2) is examined in a compilation of experimental data (n = 299) from 700 to 1050 °C, 50–900 MPa and five order of magnitude range in fO2. The XMg (=Mg/(Mg + Fetot)) of Mag is strongly dependent on T, and can be formulated into an empirical geothermometer: TMg−mag (°C) = − 8344(±320)/[lnXMg − 4.1(±0.28)] – 273 r2 = 0.83 that reproduces 72% of the experimentas to ±50 °C, and conventional Fesingle bondTi oxide thermometry in tuffs and vitrophyres to better than ±60 °C for >85% of the samples. The TMg Mag thermometer may have potential application in igneous or hydrothermally altered rocks where conventional thermometry or oxybarometry is not possible. Application to natural Mag (n = 476) compiled from several settings shows igneous rocks mostly record >700 °C but with some lower temperatures in plutonic rocks due to slow cooling. Hydrothermal samples (skarns, porphyry deposits) show consistently subsolidus conditions (TMg-mag of 700–350 °C) consistent with other mineral and O isotopic equilibria. The element correlations in natural Mag from various settings are explored using multivariate statistical analysis, to identify which minor or trace elements most critically depend on T, fO2 or fluid composition. | en_US |
| dc.description.embargo | 2022-05-20 | |
| dc.description.reviewstatus | Reviewed | en_US |
| dc.description.scholarlevel | Faculty | en_US |
| dc.description.sponsorship | This research was supported by NSERC of Canada Discovery Grants (154275, 342003) to D. Canil and T. Lacourse. | en_US |
| dc.identifier.citation | Canil, D., & Lacourse, T. (2020). Geothermometry using minor and trace elements in igneous and hydrothermal magnetite. Chemical Geology, 541, 1-11. https://doi.org/10.1016/j.chemgeo.2020.119576. | en_US |
| dc.identifier.uri | https://doi.org/10.1016/j.chemgeo.2020.119576 | |
| dc.identifier.uri | http://hdl.handle.net/1828/13115 | |
| dc.language.iso | en | en_US |
| dc.publisher | Chemical Geology | en_US |
| dc.subject | magnetite | en_US |
| dc.subject | geothermometry | en_US |
| dc.subject | experiment | en_US |
| dc.subject | partition | en_US |
| dc.subject | multivariate | en_US |
| dc.subject | hydrothermal | en_US |
| dc.title | Geothermometry using minor and trace elements in igneous and hydrothermal magnetite | en_US |
| dc.type | Postprint | en_US |