A low viscosity wedge in subduction zones

详细信息    查看全文

• 作者：Billen ; Magali I. ; Gurnis ; Michael
• 关键词：subduction zones ; viscosity ; gravity anomalies ; topography ; Tonga Trench ; Kermadec Trench
• 刊名：Earth and Planetary Science Letters
• 出版年：2001
• 出版时间：November 30, 2001
• 年：2001
• 卷：193
• 期：1-2
• 页码：227-236
• 全文大小：643 K

文摘

Geochemical, petrologic and seismological observations indicate that there may be high concentrations of water in the region above a subducting slab (the mantle wedge), which could decrease the viscosity of the mantle locally by several orders of magnitude. Using numerical models we demonstrate that a low viscosity wedge has a dramatic influence on the force balance in a subduction zone and leads to an observable signal in the topography, gravity and geoid. A regional dynamic model of the Tonga–Kermadec subduction zone shows that the viscosity of the wedge is at least a factor of 10 smaller than surrounding mantle lithosphere and asthenosphere, consistent with estimates from seismic dissipation and deformation experiments.