Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 17 December 1999:
Vol. 286. no. 5448, pp. 2323 - 2325
DOI: 10.1126/science.286.5448.2323
Prev | Table of Contents | Next

Reports

Short-Lived Oxygen Diffusion During Hot, Deep-Seated Meteoric Alteration of Anorthosite

Claudia I. Mora, 1* Lee R. Riciputi, 2 David R. Cole 2

Heterogeneous oxygen isotope compositions of plagioclase from the Boehls Butte anorthosite include some of the most oxygen-18-depleted values (to -16 per mil) reported for plagioclase in meta-igneous rocks and indicate high-temperature (T > 500°C) isotopic exchange between plagioclase and nearly pristine meteoric fluid. Retrograde reaction-enhanced permeability assisted influx of meteoric-hydrothermal fluids into the deep-seated anorthosite. Isotopic gradients of about 14 per mil over 600 micrometers in single crystals require short-lived (about 104 years) diffusional exchange of oxygen and locally large effective water:rock ratios, followed by rapid loss of water and cessation of oxygen diffusion in the anorthosite.

1 Department of Geological Sciences, University of Tennessee, Knoxville, TN 37996-1410, USA.
2 Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6365, USA.
*   To whom correspondence should be addressed. E-mail: cmora{at}utk.edu

Read the Full Text


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Structural, metamorphic, and geochronologic constraints on the origin of the Clearwater core complex, northern Idaho.
P. T. Doughty, K. R. Chamberlain, D. A. Foster, and G. S. Sha (2007)
Geological Society of America Special Papers 433, 211-241
   Abstract »    Full Text »    PDF »
Kinematics and timing of exhumation of metamorphic core complexes along the Lewis and Clark fault zone, northern Rocky Mountains, USA.
D. A. Foster, P. T. Doughty, T. J. Kalakay, C. M. Fanning, S. Coyner, W. C. Grice, and J. Vogl (2007)
Geological Society of America Special Papers 434, 207-232
   Abstract »    Full Text »    PDF »
Grain growth control of isotope exchange between rocks and fluids.
M. Nakamura, H. Yurimoto, and E. B. Watson (2005)
Geology 33, 829-832
   Abstract »    Full Text »    PDF »
Oxygen isotope zoning profiles in hydrothermally altered feldspars: Estimating the duration of water-rock interaction.
D. R. Cole, P. B. Larson, L. R. Riciputi, and C. I. Mora (2004)
Geology 32, 29-32
   Abstract »    Full Text »    PDF »
Stable and Radiogenic Isotope Systematics in Epidote Group Minerals.
J. Morrison (2004)
Reviews in Mineralogy and Geochemistry 56, 607-628
   Full Text »    PDF »
Rates and Mechanisms of Isotopic Exchange.
D. R. Cole, D. R. Cole, and S. Chakraborty (2001)
Reviews in Mineralogy and Geochemistry 43, 83-223
   Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)