skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Titanium, vanadium and chromium valences in silicates of ungrouped achondrite NWA 7325 and ureilite Y-791538 record highly-reduced origins

Authors:
; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1398652
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Geochimica et Cosmochimica Acta
Additional Journal Information:
Journal Volume: 204; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-07 10:04:25; Journal ID: ISSN 0016-7037
Publisher:
Elsevier
Country of Publication:
United States
Language:
English

Citation Formats

Sutton, S. R., Goodrich, C. A., and Wirick, S. Titanium, vanadium and chromium valences in silicates of ungrouped achondrite NWA 7325 and ureilite Y-791538 record highly-reduced origins. United States: N. p., 2017. Web. doi:10.1016/j.gca.2017.01.036.
Sutton, S. R., Goodrich, C. A., & Wirick, S. Titanium, vanadium and chromium valences in silicates of ungrouped achondrite NWA 7325 and ureilite Y-791538 record highly-reduced origins. United States. doi:10.1016/j.gca.2017.01.036.
Sutton, S. R., Goodrich, C. A., and Wirick, S. Mon . "Titanium, vanadium and chromium valences in silicates of ungrouped achondrite NWA 7325 and ureilite Y-791538 record highly-reduced origins". United States. doi:10.1016/j.gca.2017.01.036.
@article{osti_1398652,
title = {Titanium, vanadium and chromium valences in silicates of ungrouped achondrite NWA 7325 and ureilite Y-791538 record highly-reduced origins},
author = {Sutton, S. R. and Goodrich, C. A. and Wirick, S.},
abstractNote = {},
doi = {10.1016/j.gca.2017.01.036},
journal = {Geochimica et Cosmochimica Acta},
number = C,
volume = 204,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2017},
month = {Mon May 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.gca.2017.01.036

Citation Metrics:
Cited by: 3works
Citation information provided by
Web of Science

Save / Share:
  • Titanium, Cr, and V valences were determined by applying micro-X-ray Absorption Near Edge Structure (micro-XANES) spectroscopy methods to individual grains of olivine and pyroxene in the ungrouped achondrite NWA 7325 and ureilite Y-791538, as well as to plagioclase in NWA 7325. The advantages of applying multiple, multivalent-element-based oxybarometers to individual grains are (1) the ability to cover the entire oxygen fugacity (fO2) range encountered in nature, and (2) the increased reliability from consistent results for semi-independent fO2 proxies. fO2 values were inferred from each mineral valence determination after correcting with available laboratory-experiment-derived, valence-specific partition coefficients to obtain melt valences andmore » then calibrating with the fO2 values of the relevant equal species proportions points suggested for igneous (primarily basaltic) systems. The resulting olivine and pyroxene valences are highly reduced and similar in the two meteorites with substantial fractions of Cr2+, Ti3+ and V2+. The exception is Cr in NWA 7325 pyroxene which is much more oxidized than the Cr in its olivine. Chromium and Ti in plagioclase in NWA 7325 is relatively oxidized (V valence not determined). The anomalously oxidized Cr in NWA 7325 pyroxene may be due to a secondary reheating event that oxidized Cr in the pyroxene without similarly oxidizing Ti and V. Such a separation of the redox couples may be an effect of re-equilibration kinetics, where the valence of Cr would be more rapidly modified. These valences yielded similar mean fO2s for the two meteorites; IW-3.1 ± 0.2 for NWA 7325 and IW-2.8 ± 0.2 for Y-791538, consistent with an origin of NWA 7325 in either Mercury or an asteroid that experienced redox conditions similar to those on the ureilite parent body.« less
  • Thermotransport of hydrogen and deuterium in vanadium alloyed with either niobium, titanium, or chromium is much greater than in pure vanadium, and additions of vanadium to niobium similarly increase thermotransport of hydrogen and deuterium over that observed in pure niobium. In all cases, the heat of transport was positive and was significantly greater for deuterium than for hydrogen. The results are consistent with an atomistic model in which the temperature dependence of atomic jump frequencies is the dominant factor in thermotransport with a small bias in the direction of atomic jumps. There is evidence that differences between the heats ofmore » transport for hydrogen and deuteriu may be related to isotope effects in the activation energies for diffusion.« less