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 Web of Science (9) Citing Articles via Google Scholar Google Scholar Articles by Carter, T. J. Articles by Gleadow, A. J.W. Search for Related Content GeoRef GeoRef Citation

How the Harcuvar Mountains metamorphic core complex became cool: Evidence from apatite (U-Th)/He thermochronometry

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

Apatite (U-Th)/He (AHe) data from 60 km of exposed footwall in the Harcuvar Mountains metamorphic core complex, Arizona, reveal a higher-precision late-stage cooling history than previously reported for this complex and others in the region. Progressively younger AHe ages recorded with distance along the slip direction show two distinct trends separated by a sharp inflection. At structurally shallower levels, ages decrease from ca. 23 to 15 Ma toward the northeast, defining an estimated slip rate of 2.6 +0.1/–0.2 km/ m.y. Samples from the structurally deepest 35 km of footwall yield concordant ages of ca. 15 Ma (±2 error limits). The effects of mineralizing fluids, advection of isotherms toward the surface, and flexure-induced erosion are considered, but are unlikely to have influenced the ages. Therefore, it is suggested that the fault slip rate must have increased ca. 15 Ma to a rate of 30 km/m.y. Evidence for an increased slip rate ca. 15 Ma has also been observed in other metamorphic core complexes nearby, and this increase is attributed to the thermal effects of a slab-free window on the extending lithosphere.

Key Words: (U-Th)/He • thermochronology • detachment faults • metamorphic core complexes • Arizona

This article has been cited by other articles:

				S. N. Thomson, U. Ring, S. Brichau, J. Glodny, and T. M. Will Timing and nature of formation of the Ios metamorphic core complex, southern Cyclades, Greece Geological Society, London, Special Publications, January 1, 2009; 321(1): 139 - 167. [Abstract] [Full Text] [PDF]

				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]

				D. A. Foster and D. R. Gray Strain rate in Paleozoic thrust sheets, the western Lachlan Orogen, Australia: Strain analysis and fabric geochronology Geological Society of America Special Papers, January 1, 2007; 433(0): 349 - 368. [Abstract] [Full Text] [PDF]

				T. J. Carter, B. P. Kohn, D. A. Foster, A. J.W. Gleadow, and J. D. Woodhead Late-stage evolution of the Chemehuevi and Sacramento detachment faults from apatite (U-Th)/He thermochronometry--Evidence for mid-Miocene accelerated slip Geological Society of America Bulletin, May 1, 2006; 118(5-6): 689 - 709. [Abstract] [Full Text] [PDF]

				D. F. Stockli Application of Low-Temperature Thermochronometry to Extensional Tectonic Settings Reviews in Mineralogy and Geochemistry, January 1, 2005; 58(1): 411 - 448. [Full Text] [PDF]