Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wolff, J. A. Articles by Ellisor, R. Search for Related Content GeoRef GeoRef Citation

Hybrid origin of Rio Grande rift hawaiites

¹ Department of Geology, Washington State University, Pullman, Washington 99164, USA
² Department of Geology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4MI, Canada
³ Department of Geology and Geological Engineering, University of Idaho, Moscow, Idaho 83844, USA

Weakly alkaline lavas erupted in the Pliocene Cerros del Rio and El Alto volcanic fields in the Española basin of the Rio Grande rift have the unusual trace element signature of approximately chondritic K/Nb combined with high La/Nb and Th/Nb. These lavas have previously been interpreted as the products of modified arc-source–like mantle, ultimately related to subduction of the Farallon plate beneath North America during the early Cenozoic. We show that the chemical signature can be produced by contamination of strongly silica undersaturated K-depleted magmas by continental crust, and that there is no need to invoke a subduction component in Rio Grande rift magma genesis. The same signature appears among voluminous Miocene lavas of the Jemez Mountains volcanic field. Hence, while nephelinite and basanite magmas resembling oceanic island basalts have been recognized as trace components in Rio Grande rift magmatism, our results may require a drastic upward revision of their volumetric significance in the northern rift through late Miocene-Pliocene time.

Key Words: Rio Grande rift • hawaiite • nephelinite • crustal contamination • trace elements

This article has been cited by other articles:

				M. C. Rowe, J. A. Wolff, J. N. Gardner, F. C. Ramos, R. Teasdale, and C. E. Heikoop Development of a Continental Volcanic Field: Petrogenesis of Pre-caldera Intermediate and Silicic Rocks and Origin of the Bandelier Magmas, Jemez Mountains (New Mexico, USA) J. Petrology, November 1, 2007; 48(11): 2063 - 2091. [Abstract] [Full Text] [PDF]

				J. A. WOLFF, M. C. ROWE, R. TEASDALE, J. N. GARDNER, F. C. RAMOS, and C. E. HEIKOOP Petrogenesis of Pre-caldera Mafic Lavas, Jemez Mountains Volcanic Field (New Mexico, USA) J. Petrology, February 1, 2005; 46(2): 407 - 439. [Abstract] [Full Text] [PDF]