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DOI	10.1016/j.epsl.2020.116237
	Intracrystalline site preference of oxygen isotopes in goethite: A single-mineral paleothermometer
	Miller H.B.D.; Farley K.A.; Vasconcelos P.M.; Mostert A.; Eiler J.M.
发表日期	2020
ISSN	0012821X
卷号	539
英文摘要	The crystal structure of goethite, FeO(OH), has two distinct oxygen sites, one with exclusively Fe-O bonds, the other with bonds to both iron and hydrogen. We developed a method to assess the oxygen isotope contrast between these sites by measuring both the bulk goethite and the oxygen released in the conversion of goethite to hematite. The method involves collecting the water released by dehydroxylation, fluorinating that population of extracted atoms, and measuring the resulting oxygen isotope composition (extracted δO18). Then, on a separate aliquot, all structural oxygen is fluorinated and measured (bulk δO18). Using synthetic goethite precipitates grown under controlled environmental conditions, we found significant temperature-dependent fractionation, εbulk-extracted=(5.51±0.26)×(106/T2)−(44.5±2.8); T in Kelvin). This intracrystalline fractionation forms the basis of a single-phase paleothermometer with an estimated uncertainty of ∼2-3°C. The temperature dependence appears to be independent of the isotopic composition of the parent fluid from which the goethite formed and the pH of that fluid. This intracrystalline thermometer can be used to simultaneously determine the formation temperature of a goethite and the isotopic composition of the water from which it formed. Natural goethites analyzed with this technique yield geologically reasonable formation temperatures of between 15 and 41°C. © 2020 Elsevier B.V.
关键词	geochronology goethite iron oxide oxygen isotopes paleoclimate weathering
英文关键词	Geochronology; Hematite; Hydrogen bonds; Iron oxides; Isotopes; Oxygen; Temperature distribution; Uncertainty analysis; Weathering; Environmental conditions; Formation temperature; goethite; Oxygen isotope composition; Oxygen isotopes; Paleoclimates; Temperature dependence; Temperature dependent; Crystal structure; chemical weathering; crystal chemistry; crystal structure; experimental mineralogy; formation mechanism; geochronology; goethite; iron oxide; isotopic composition; oxygen isotope; paleoclimate; paleotemperature; temperature profile; thermometry
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202787
作者单位	Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, United States; School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, United States; School of Earth Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
推荐引用方式 GB/T 7714	Miller H.B.D.,Farley K.A.,Vasconcelos P.M.,et al. Intracrystalline site preference of oxygen isotopes in goethite: A single-mineral paleothermometer[J],2020,539.
APA	Miller H.B.D.,Farley K.A.,Vasconcelos P.M.,Mostert A.,&Eiler J.M..(2020).Intracrystalline site preference of oxygen isotopes in goethite: A single-mineral paleothermometer.Earth and Planetary Science Letters,539.
MLA	Miller H.B.D.,et al."Intracrystalline site preference of oxygen isotopes in goethite: A single-mineral paleothermometer".Earth and Planetary Science Letters 539(2020).