Newtonian versus non-Newtonian upper mantle viscosity : implications for subduction initiation
MetadataShow full item record
KeywordDynamics of lithosphere and mantle; Plate boundary; Rheology: mantle; Subduction zone processes
The effect of rheology on the evolution of the slab-tip during subduction initiation is analyzed using 2-D numerical flow models. Experimentally determined flow laws have both strong temperature- and stress-dependence, which leads to large local variations in viscosity with direct consequences for subduction initiation. We find that models with Newtonian viscosity lead to flat or coupled subduction due to hydrodynamic stresses that pull the slab-tip up towards the overriding plate. Non-Newtonian rheology reduces these hydrodynamic stresses by decreasing the wedge viscosity and the slab coupling to wedge-corner flow, rendering the small negative-slab buoyancy of the slab-tip sufficient to maintain its dip during the early stages of subduction.
Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 32 (2005): L19304, doi:10.1029/2005GL023457.
Suggested CitationArticle: Billen, Magali I., Hirth, Greg, "Newtonian versus non-Newtonian upper mantle viscosity : implications for subduction initiation", Geophysical Research Letters 32 (2005): L19304, DOI:10.1029/2005GL023457, https://hdl.handle.net/1912/294
Showing items related by title, author, creator and subject.
Wada, Ikuko; Behn, Mark D.; He, Jiangheng (American Geophysical Union, 2011-10-20)Mineral grain size plays an important role in controlling many processes in the mantle wedge of subduction zones, including mantle flow and fluid migration. To investigate the grain-size distribution in the mantle wedge, ...
Evolution of oceanic margins : rifting in the Gulf of California and sediment diapirism and mantle hydration during subduction Miller, Nathaniel C. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2013-06)This thesis investigates three processes that control the evolution of oceanic margins. Chapter 2 presents seismic images of a ~2-km-thick evaporite body in Guaymas Basin, central Gulf of California. In rifts, evaporites ...