Le Pourhiet, Laetitia and Gurnis, Michael and Saleeby, Jason (2006) Mantle instability beneath the Sierra Nevada Mountains in California and Death Valley extension. Earth and Planetary Science Letters, 251 (1-2). pp. 104-119. ISSN 0012-821X http://resolver.caltech.edu/CaltechAUTHORS:20101116-101724895
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The Southern Sierra Nevada mountain range rapidly uplifted at ≈ 3.5 Ma simultaneously with a pulse of basaltic volcanism. Xenoliths recovered from volcanics indicate that the range lost a dense crustal root after the Miocene. The vertical motions and removal of the root have been linked to a fast seismic velocity anomaly that extends ≈ 200 km into the mantle but is offset to the west of the range. With visco-elasto-plastic thermo-mechanical numerical models, we have tested the influence of crustal strength on the kinematics of removal and on the amount of associated uplift. We find that delamination of the dense root is the most likely mechanism for gravitational instability to occur. The model satisfies the Plio-Quaternary vertical motions, the shift of the mantle anomaly to the west of the range, and intense Miocene extension to the east. Based on those results, we propose the existence of a dynamic link between the Sierra Nevada mantle instability and Death Valley rifting.
|Additional Information:||© 2006 Elsevier B.V. Received 25 April 2006; revised 29 August 2006; accepted 30 August 2006. Editor: Scott King. Available online 11 October 2006. This represents contribution number 9156 of the Division of Geological and Planetary Sciences and 35 of the Tectonics Observatory. Partially supported by the NSF under EAR-0205653 and the Gordon and Betty Moore Foundation. We thank Zorka Foster for help with the structural map and fruitful discussion. We thank Muriel Gerbault, an anonymous reviewer, and Scott King for helping to improve the manuscript and A. Poliakov and Y. Podladchikov, the main contributors to Paravoz, for access to their code.|
|Group:||Caltech Tectonics Observatory|
|Subject Keywords:||gravitational instability; Sierra Nevada; Death Valley; Cordilleran Arcs dynamic; thenno-mechanical modeling|
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|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||17 Nov 2010 19:39|
|Last Modified:||26 Dec 2012 12:38|
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