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 Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Carter, T. J. Articles by Woodhead, J. D. Search for Related Content GeoRef GeoRef Citation

Late-stage evolution of the Chemehuevi and Sacramento detachment faults from apatite (U-Th)/He thermochronometry—Evidence for mid-Miocene accelerated slip

Timothy J. Carter^,1, Barry P. Kohn¹, David A. Foster², Andrew J.W. Gleadow³ and Jon D. Woodhead³

¹ School of Earth Sciences, The University of Melbourne, 3010, Victoria, Australia
² Department of Geological Sciences, University of Florida, Gainesville, Florida 32611, USA
³ School of Earth Sciences, The University of Melbourne, 3010, Victoria, Australia

The unique low-temperature sensitivity of the apatite (U-Th)/He (AHe) technique provides valuable new information relating to the late-stage thermal evolution of metamorphic core complexes in the southern Basin and Range Province. In all the ranges studied, the data show greater complexity than previously seen from other thermochronometers. In the Chemehuevi and northern Sacramento Mountains, a trend of decreasing ages toward the northeast applies only for the structurally shallowest parts of the footwall. This is followed by essentially age-invariant segments of 15 ± 1 Ma, reflecting an increase in the rate of detachment fault movement. The timing of the change suggested by the data agrees with recently published AHe results from the nearby Harcuvar Mountains, located 125 km to the southeast, suggesting that an underlying regional mechanism triggered this change. Plate reconstructions indicate that the Pioneer-Mendocino fracture zone migrated northward through the area at this time, leaving a slab window in its wake. We suggest that the additional heat applied to the base of the lithosphere from the slab window resulted in mechanical weakening of the area and that this, combined with the extensional strain regime present, resulted in an increased rate of slip within the actively extending metamorphic core complexes. This agrees well with timing constraints for extension onset in the central Basin and Range Province of southern Nevada, and suggests that weakening of the southern Basin and Range Province at 15 ± 1 Ma was partially responsible for the onset of extension in the central Basin and Range. These findings demonstrate that improved constraints on changes in extension rate within the Basin and Range Province should be possible through the application of the AHe technique to other metamorphic core complex footwalls.

Key Words: metamorphic core complexes • Basin and Range Province • low-angle normal faults • (U-Th)/He • low-temperature thermochronology

This article has been cited by other articles:

				J. P. Colgan, T. A. Dumitru, P. W. Reiners, J. L. Wooden, and E. L. Miller Cenozoic Tectonic Evolution of the Basin and Range Province in Northwestern Nevada Am J Sci, October 1, 2006; 306(8): 616 - 654. [Abstract] [Full Text] [PDF]