Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Geology Signup for GSW Email News
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Geology; November 2003; v. 31; no. 11; p. 953-956; DOI: 10.1130/G19843.1
© 2003 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 Google Scholar
Google Scholar
Right arrow Articles by Wong, M. S.
Right arrow Articles by Gans, P. B.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

Tectonic implications of early Miocene extensional unroofing of the Sierra Mazatán metamorphic core complex, Sonora, Mexico

Martin S. Wong*,1 and Phillip B. Gans*,1

1 Department of Geological Sciences, University of California, Santa Barbara, California 93106, USA

Sierra Mazatán in northwest Mexico is the southernmost metamorphic core complex in the North American Cordillera. New geologic, structural, and 40Ar/39Ar thermochronologic data demonstrate that the core complex detachment fault accommodated 15–35 km of slip at a rate of 3.3–7.7 mm/yr between 20.5 and 16 Ma. These data also suggest that the lower plate was tilted eastward 20°–50° since 20 Ma, indicating that the detachment fault initially dipped 30°–60°. Rapid slip on the fault occurred concurrently with subduction in Sonora and thus was not related to the ca. 12 Ma plate boundary change at this latitude or the late Miocene opening of the Gulf of California. Rapid extension at Sierra Mazatán was synchronous with core complexes along the length of the Cordillera, suggesting a distinct 20–15 Ma core complex event, the fundamental causes of which remain a mystery.

Key Words: metamorphic core complexes • extension • detachment faults • Ar/Ar • thermochronology




This article has been cited by other articles:


Home page
 Journal of the Geological SocietyHome page
J.P. PLATT
From orogenic hinterlands to Mediterranean-style back-arc basins: a comparative analysis
Journal of the Geological Society, March 1, 2007; 164(2): 297 - 311.
[Abstract] [Full Text] [PDF]

Home page
 Geological Society of America Special PapersHome page
C. E. Jacobson, M. Grove, A. Vucic, J. N. Pedrick, and K. A. Ebert
Exhumation of the Orocopia Schist and associated rocks of southeastern California: Relative roles of erosion, synsubduction tectonic denudation, and middle Cenozoic extension
Geological Society of America Special Papers, January 1, 2007; 419(0): 1 - 37.
[Abstract] [Full Text] [PDF]

Home page
 Geological Society of America Special PapersHome page
L. Ferrari, M. Valencia-Moreno, and S. Bryan
Magmatism and tectonics of the Sierra Madre Occidental and its relation with the evolution of the western margin of North America
Geological Society of America Special Papers, January 1, 2007; 422(0): 1 - 39.
[Abstract] [Full Text] [PDF]

Home page
 Geological Society of America Special PapersHome page
R. A. Armstrong, C. Lana, W. Uwe Reimold, and R. L. Gibson
SHRIMP zircon age constraints on Mesoarchean crustal development in the Vredefort dome, central Kaapvaal Craton, South Africa
Geological Society of America Special Papers, January 1, 2006; 405(0): 233 - 253.
[Abstract] [Full Text] [PDF]


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