CaltechAUTHORS
  A Caltech Library Service

Stalled slab dynamics

Burkett, Erin and Gurnis, Michael (2013) Stalled slab dynamics. Lithosphere, 5 (1). pp. 92-97. ISSN 1941-8264. http://resolver.caltech.edu/CaltechAUTHORS:20130405-084857740

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20130405-084857740

Abstract

Recent seismic imaging of the mantle beneath western North America reveals complexities interpreted as structures ranging from plumes to lithospheric drips and slab fragments. A prominent high-velocity "curtain" beneath Idaho has been interpreted as a remnant of the subducted Farallon plate left dangling within the upper mantle since >40 Ma. Consequently, using numerical models, we explore the rheological, chemical, geometrical, and dynamic conditions under which a slab fragment might persist in the mantle for tens of millions of years. With thermal buoyancy alone, stalled slabs extending to 500 km depth tend to detach and sink vertically within ∼17 m.y. for the slab age and rheologic conditions explored here, and shorter slabs <300 km deep have the greatest impact on delaying detachment up to 28 m.y. Otherwise, we find that an unrealistic chemical density contrast of 90 kg/m^3 with respect to the mantle is required for the stalled slab to remain attached to the lithosphere >40 m.y. An increase in upper- to lower-mantle viscosity contrast (1.4× to 100×) can slow sinking velocities and extend slab dangling time by up to 5 m.y. Dynamic effects such as those arising from active nearby subduction only slightly delay or do not affect stalled slab detachment timing but do affect the geometry of the slabs as they respond to suction pressures within the wedge. Overall, a combination of buoyant, viscous, geometric, and dynamic factors may allow cases of extended slab stalling, and conditions we explore here within realistic ranges can so far account for a delay of up to 28 m.y.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1130/L249.1DOIUNSPECIFIED
http://lithosphere.gsapubs.org/content/5/1/92PublisherUNSPECIFIED
http://lithosphere.geoscienceworld.org/content/5/1/92PublisherUNSPECIFIED
Additional Information:© 2012 Geological Society of America. Manuscript Received 20 July 2012; Revised Manuscript Received 21 September 2012; Manuscript Accepted 24 September 2012. First published online October 26, 2012. This work was supported by the National Science Foundation (CMMI-1028978), and the Caltech Tectonics Observatory (by the Gordon and Betty Moore Foundation). The original CitcomS software was obtained from CIG, Computational Infrastructure for Geodynamics (http://geodynamics.org), and code modifications for the shear zone and composite viscosity were made by Magali I. Billen. This is contribution 205 of the Tectonics Observatory, Caltech. We thank T.V. Gerya and V.C. Manea for constructive comments and M. Billen for discussions.
Group:Caltech Tectonics Observatory, Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFCMMI-1028978
Caltech Tectonics ObservatoryUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Tectonics Observatory205
Record Number:CaltechAUTHORS:20130405-084857740
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20130405-084857740
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37776
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:08 Apr 2013 22:23
Last Modified:11 Jun 2015 12:44

Repository Staff Only: item control page