DOI: 10.1016/j.epsl.2017.11.032
Scopus记录号: 2-s2.0-85038420468
论文题名: A re-assessment of the oxidation state of iron in MORB glasses
作者: Berry A.J. ; Stewart G.A. ; O'Neill H.S.C. ; Mallmann G. ; Mosselmans J.F.W.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 483 起始页码: 114
结束页码: 123
语种: 英语
英文关键词: Fe3+/Fe2+
; MORB
; Mössbauer spectroscopy
; oxygen fugacity
; XANES spectroscopy
Scopus关键词: Structural geology
; Thermal logging
; X ray absorption near edge structure spectroscopy
; Calibration error
; Mid ocean ridge basalts
; MORB
; Morb compositions
; Oxygen fugacity
; Quadrupole splitting
; Ssbauer spectroscopies
; Temperature independents
; Glass
; fugacity
; glass
; iron
; mid-ocean ridge basalt
; Mossbauer spectroscopy
; oxidation
; XANES spectroscopy
英文摘要: The oxidation state of Fe, Fe/3+ΣFe (where ΣFe=Fe2++Fe3+), in glass samples of mid-ocean ridge basalt (MORB), from a wide range of localities, was determined by XANES spectroscopy to be 0.10(2) (n=42). This value is lower than that reported previously by XANES, 0.16(1) (n=103), but consistent with the most recent value determined by redox titrations, 0.11(2) (n=104), all for similar sets of samples. We attribute the anomalously high XANES value of 0.16 to a calibration error resulting from the interpretation of Mössbauer spectra and the resulting Fe/3+ΣFe values of the standards. Our alternative interpretation removes the problem of resolving Fe/3+ΣFe values <∼0.1 in basaltic glasses, produces isomer shift and quadrupole splitting values for Fe3+ that are independent of Fe3+/ΣFe (as is the case for Fe2+), and gives Fe/3+ΣFe values that are consistent with the thermodynamically expected dependence on oxygen fugacity (fO2). Fe/3+Fe2+ is related to fO2 for our synthetic MORB composition by the temperature independent expression ΔQFM=4log(Fe3+/Fe2+)+4.23(5), where ΔQFM is the fO2 in log units relative to the quartz–fayalite–magnetite buffer. The average fO2 of natural MORB was estimated to be QFM+0.1. © 2017 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110092
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
There are no files associated with this item.
作者单位: Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia; Department of Earth Science and Engineering, Imperial College London, South Kensington, SW7 2AZ, United Kingdom; School of Physical, Environmental and Mathematical Sciences, UNSW Canberra at the Australian Defence Force Academy, PO Box 7916, Canberra BC, ACT 2610, Australia; Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, United Kingdom
Recommended Citation:
Berry A.J.,Stewart G.A.,O'Neill H.S.C.,et al. A re-assessment of the oxidation state of iron in MORB glasses[J]. Earth and Planetary Science Letters,2018-01-01,483