Journal of Petrology Advance Access originally published online on June 13, 2005
Journal of Petrology 2005 46(11):2313-2336; doi:10.1093/petrology/egi056
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Similar V/Sc Systematics in MORB and Arc Basalts: Implications for the Oxygen Fugacities of their Mantle Source Regions
1 DEPARTMENT OF EARTH SCIENCES, MS-126, RICE UNIVERSITY, 6100 MAIN STREET, HOUSTON, TX 77005, USA
2 SCHOOL OF EARTH AND OCEAN SCIENCES, UNIVERSITY OF VICTORIA, PETCH BUILDING, ROOM 280, 3800 FINNERTY ROAD, VICTORIA, BC, CANADA V8W 3P6
RECEIVED JULY 15, 2004; ACCEPTED MAY 3, 2005
V/Sc systematics in peridotites, mid-ocean ridge basalts and arc basalts are investigated to constrain the variation of fO2 in the asthenospheric mantle. V/Sc ratios are used here to ‘see through’ those processes that can modify barometric fO2 determinations in mantle rocks and/or magmas: early fractional crystallization, degassing, crustal assimilation and mantle metasomatism. Melting models are combined here with a literature database on peridotites, arc lavas and mid-ocean ridge basalts, along with new, more precise data on peridotites and selected arc lavas. V/Sc ratios in primitive arc lavas from the Cascades magmatic arc are correlated with fluid-mobile elements (e.g. Ba and K), indicating that fluids may subtly influence fO2 during melting. However, for the most part, the average V/Sc-inferred fO2s of arc basalts, MORB and peridotites are remarkably similar (–1·25 to +0·5 log units from the FMQ buffer) and disagree with the observation that the barometric fO2s of arc lavas are several orders of magnitude higher. These observations suggest that the upper part of the Earth's mantle may be strongly buffered in terms of fO2. The higher barometric fO2s of arc lavas and some arc-related xenoliths may be due respectively to magmatic differentiation processes and to exposure to large, time-integrated fluid fluxes incurred during the long-term stability of the lithospheric mantle.
KEY WORDS: vanadium; scandium; oxygen fugacity; mantle; arcs
* Corresponding author. Telephone: 1-713-348-5084. E-mail: ctlee{at}rice.edu
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  G. Mallmann and H. St. C. O'Neill The Crystal/Melt Partitioning of V during Mantle Melting as a Function of Oxygen Fugacity Compared with some other Elements (Al, P, Ca, Sc, Ti, Cr, Fe, Ga, Y, Zr and Nb) J. Petrology, September 1, 2009; 50(9): 1765 - 1794. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Malaspina, S. Poli, and P. Fumagalli The Oxidation State of Metasomatized Mantle Wedge: Insights from C-O-H-bearing Garnet Peridotite J. Petrology, August 1, 2009; 50(8): 1533 - 1552. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. M. Hirschmann Ironing Out the Oxidation of Earth's Mantle Science, July 31, 2009; 325(5940): 545 - 546. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. A. Kelley and E. Cottrell Water and the Oxidation State of Subduction Zone Magmas Science, July 31, 2009; 325(5940): 605 - 607. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. C. Rowe, A. J. R. Kent, and R. L. Nielsen Subduction Influence on Oxygen Fugacity and Trace and Volatile Elements in Basalts Across the Cascade Volcanic Arc J. Petrology, January 7, 2009; (2009) egn072v1. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. D. K. Herd Basalts as Probes of Planetary Interior Redox State Reviews in Mineralogy and Geochemistry, January 1, 2008; 68(1): 527 - 553. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K.A. Evans Redox decoupling and redox budgets: Conceptual tools for the study of earth systems Geology, June 1, 2006; 34(6): 489 - 492. [Abstract] [Full Text] [PDF]
|
|