Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Geology Email Content Delivery
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Geology; April 2004; v. 32; no. 4; p. 293-296; DOI: 10.1130/G20109.1
© 2004 Geological Society of America
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
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 Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (6)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Durand, S. R.
Right arrow Articles by Sen, G.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

Preeruption history of the Grande Ronde Formation lavas, Columbia River Basalt Group, American Northwest: Evidence from phenocrysts

Sedelia Rodriguez Durand1 and Gautam Sen*,1

1 Department of Earth Sciences and Florida Center for Analytical Electron Microscopy, Florida International University, Miami, Florida 33199, USA

Basaltic andesite lavas belonging to the Grande Ronde Formation constitute ~87% of the Columbia River Basalt Group. Although these lavas are chemically evolved, they generally contain <5% phenocrysts. Two hypotheses have been proposed to explain this observation. The first hypothesis suggests that Grande Ronde lavas were near-primary melts generated by large-scale melting of eclogite from the inferred Yellowstone plume. The alternative hypothesis proposes that Grande Ronde magmas were extremely hydrous and rose rapidly from the mantle such that the dissolved water kept the magmas close to their liquidi. We present new information on textures and mineral chemistry of phenocrysts in two well-characterized field sections through the Grande Ronde Formation. The new data lead us to conclude that at least some of the Grande Ronde primary magmas were highly hydrous; however, they all underwent extensive fractionation, magma mixing, and degassing in a shallow intrusive network prior to eruption as lava.

Key Words: flood basalts • Columbia River Basalt Group • phase equilibria • magma mixing • basalt crystallization




This article has been cited by other articles:


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
 GeosphereHome page
V. E. Camp and B. B. Hanan
A plume-triggered delamination origin for the Columbia River Basalt Group
Geosphere, June 1, 2008; 4(3): 480 - 495.
[Abstract] [Full Text] [PDF]

Home page
 J PetrologyHome page
B. SCAILLET and R. MACDONALD
Experimental and Thermodynamic Constraints on the Sulphur Yield of Peralkaline and Metaluminous Silicic Flood Eruptions
J. Petrology, July 1, 2006; 47(7): 1413 - 1437.
[Abstract] [Full Text] [PDF]

Home page
 GeologyHome page
F. C. Ramos, J. A. Wolff, and D. L. Tollstrup
Sr isotope disequilibrium in Columbia River flood basalts: Evidence for rapid shallow-level open-system processes
Geology, June 1, 2005; 33(6): 457 - 460.
[Abstract] [Full Text] [PDF]


JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by Geological Society of America