Skip Navigation



Journal of Petrology Advance Access published online on October 1, 2004
Journal of Petrology, doi:10.1093/petrology/egh066
This Article
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
46/1/135    most recent
egh066v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by BERNDT, J.
Right arrow Articles by HOLTZ, F.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Received April 15, 2002
Accepted July 28, 2004

Article

An Experimental Investigation of the Influence of Water and Oxygen Fugacity on Differentiation of MORB at 200 MPa

JASPER BERNDT 1*, JÜRGEN KOEPKE 1, and FRANÇOIS HOLTZ 1

1 INSTITUT FÜR MINERALOGIE, UNIVERSITÄT HANNOVER, WELFENGARTEN 1, D-30167 HANNOVER, GERMANY

* To whom correspondence should be addressed. E-mail: jberndt{at}uni-muenster.de.


  Abstract

Crystallization experiments were performed at 200 MPa in the temperature range 1150-950°C at oxygen fugacities corresponding to the quartz-fayalite-magnetite (QFM) and MnO-Mn3O4 buffers to assess the role of water and fOO2 on phase relations and differentiation trends in mid-ocean ridge basalt (MORB) systems. Starting from a primitive (MgO 9·8 wt %) and an evolved MORB (MgO 6·49 wt %), crystallization paths with four different water contents (0·35-4·7 wt % H2O) have been investigated. In primitive MORB, olivine is the liquidus phase followed by plagioclase + clinopyroxene. Amphibole is present only at water-saturated conditions below 1000°C, but not all fluid-saturated runs contain amphibole. Magnetite and orthopyroxene are not stable at low fOO2 (QFM buffer). Residual liquids obtained at low fOO2 show a tholeiitic differentiation trend. The crystallization of magnetite at high fOO2 (MnO-Mn3O4 buffer) results in a decrease of melt FeO*/MgO ratio, causing a calc-alkaline differentiation trend. Because the magnetite crystallization temperature is nearly independent of the H2O content, in contrast to silicate minerals, the calc-alkaline differentiation trend is more pronounced at high water contents. Residual melts at 950°C in a primitive MORB system have compositions approaching those of oceanic plagiogranites in terms of SiO2 and K2O, but have Ca/Na ratios and FeO* contents that are too high compared with the natural rocks, implying that fractionation processes are necessary to reach typical compositions of natural oceanic plagiogranites.

Keywords: differentiation; MORB; oxygen fugacity; water activity; oceanic plagiogranite.
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 American MineralogistHome page
P. Thy, C. Tegner, and C. E. Lesher
Liquidus temperatures of the Skaergaard magma
American Mineralogist, October 1, 2009; 94(10): 1371 - 1376.
[Abstract] [Full Text] [PDF]

Home page
 J PetrologyHome page
M. Pichavant, I. Di Carlo, Y. Le Gac, S. G. Rotolo, and B. Scaillet
Experimental Constraints on the Deep Magma Feeding System at Stromboli Volcano, Italy
J. Petrology, April 1, 2009; 50(4): 601 - 624.
[Abstract] [Full Text] [PDF]

Home page
 ajsHome page
M. S. Ghiorso and B. W. Evans
Thermodynamics of Rhombohedral Oxide Solid Solutions and a Revision of the FE-TI Two-Oxide Geothermometer and Oxygen-Barometer
Am J Sci, November 1, 2008; 308(9): 957 - 1039.
[Abstract] [Full Text] [PDF]

Home page
 J PetrologyHome page
R. E. Botcharnikov, R. R. Almeev, J. Koepke, and F. Holtz
Phase Relations and Liquid Lines of Descent in Hydrous Ferrobasalt--Implications for the Skaergaard Intrusion and Columbia River Flood Basalts
J. Petrology, September 1, 2008; 49(9): 1687 - 1727.
[Abstract] [Full Text] [PDF]

Home page
 Reviews in Mineralogy and GeochemistryHome page
J. E. Hammer
Experimental Studies of the Kinetics and Energetics of Magma Crystallization
Reviews in Mineralogy and Geochemistry, January 1, 2008; 69(1): 9 - 59.
[Full Text] [PDF]

Home page
 J PetrologyHome page
R. Almeev, F. Holtz, J. Koepke, K. Haase, and C. Devey
Depths of Partial Crystallization of H2O-bearing MORB: Phase Equilibria Simulations of Basalts at the MAR near Ascension Island (7 11{degrees}S)
J. Petrology, January 1, 2008; 49(1): 25 - 45.
[Abstract] [Full Text] [PDF]

Home page
 J PetrologyHome page
Y. Suzuki and S. Nakada
Remobilization of Highly Crystalline Felsic Magma by Injection of Mafic Magma: Constraints from the Middle Sixth Century Eruption at Haruna Volcano, Honshu, Japan
J. Petrology, August 1, 2007; 48(8): 1543 - 1567.
[Abstract] [Full Text] [PDF]

Home page
 American MineralogistHome page
R. R. Almeev, F. Holtz, J. Koepke, F. Parat, and R. E. Botcharnikov
The effect of H2O on olivine crystallization in MORB: Experimental calibration at 200 MPa
American Mineralogist, April 1, 2007; 92(4): 670 - 674.
[Abstract] [Full Text] [PDF]

Home page
 J PetrologyHome page
S. Villiger, P. Ulmer, and O. Muntener
Equilibrium and Fractional Crystallization Experiments at 0{middle dot}7 GPa; the Effect of Pressure on Phase Relations and Liquid Compositions of Tholeiitic Magmas
J. Petrology, January 1, 2007; 48(1): 159 - 184.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.