Plug flow in the Earth's asthenosphere

The Impact of a Very Weak and Thin Upper Asthenosphere on Subduction Motions

“…This flow can be driven by the plates themselves (Couette flow), pressure driven by the flow within the mantle (Poiseuille flow), or a combination of the two (combined Couette-Poiseuille flow). Several authors (e.g., Buffett & Becker, 2012;Conrad & Hager, 1999;Gerardi & Ribe, 2018;Gerardi et al, 2019;Ribe, 1992Ribe, , 2001Ribe, , 2010Stegman et al, 2010;Semple & Lenardic, 2018, Richards & Lenardic, 2018) that the force balance of the oceanic lithosphere is controlled by the balance of both bending-stretching momentum and boundary and internal stresses (flow in the boundary layer). Some of these authors (i.e., Gerardi & Ribe, 2018;Gerardi et al, 2019;Ribe, 1992Ribe, , 2001 show that the motion of a mantle fluid in an interface layer can be approximated with the motion of a Stokes fluid in the lubrication limit.…”

“…Previous global numerical models (i.e. Becker, 2017;Bercovici, 1996;Capitanio et al, 2007Capitanio et al, , 2009Gérault et al, 2012;Goes et al, 2017;Höink et al, 2011Höink et al, , 2012Lithgow-Bertelloni & Richards, 1995;Stegman et al, 2010;Tackley, 2000;Zhong et al, 1998) analyzed the role of an LVZ, but only a few have accounted for an LVZ of a limited thickness within the range of ∼100-200-km (Becker, 2017;Richards & Lenardic, 2018;Semple & Lenardic, 2018). Generally, an asthenosphere seems to better characterize plate-like behavior, improving our ability to match with observed surface velocities (Gérault et al, 2012;Tackley, 2000).…”

Dynamics of the lithosphere and upper mantle in light of seismic anisotropy

“…The sense of asthenospheric shear may thus be at large angles to APM orientations. Moreover, the degree to which asthenospheric flow is of the plug (Poiseuille) type matters because the depth distribution of strain-rates will be different for each case [Natarov and Conrad, 2012;Becker, 2017;Semple and Lenardic, 2018]. These effects are likely most relevant for slowly moving plates.…”

Uncertainties in Trends of Young Hot Spot Tracks

“…These problems include, but are not limited to, the estimation of velocities (and associated uncertainties) of the migration of trenches (Faccenna et al, 2007;Schellart et al, 2008), resolving the motion of ultraslow-moving plates such as Eurasia and Antarctica (Zheng et al, 2014), resolving motion between groups of hot spots (Wang et al, 2017), resolving motion of hot spots relative to the spin axis (e.g., Morgan, 1981;Gordon & Cape, 1981;Besse & Courtillot, 1991;Petronotis et al, 1994;Tarduno & Cottrell, 1997;Torsvik et al, 2002;Zheng et al, 2018), and unraveling the origins of upper mantle anisotropy (e.g., Becker et al, 2014;Beghein et al, 2014Beghein et al, , 2018Semple & Lenardic, 2018;VanderBeek & Toomey, 2017;Zheng et al, 2014). These problems include, but are not limited to, the estimation of velocities (and associated uncertainties) of the migration of trenches (Faccenna et al, 2007;Schellart et al, 2008), resolving the motion of ultraslow-moving plates such as Eurasia and Antarctica (Zheng et al, 2014), resolving motion between groups of hot spots (Wang et al, 2017), resolving motion of hot spots relative to the spin axis (e.g., Morgan, 1981;Gordon & Cape, 1981;Besse & Courtillot, 1991;Petronotis et al, 1994;Tarduno & Cottrell, 1997;Torsvik et al, 2002;Zheng et al, 2018), and unraveling the origins of upper mantle anisotropy (e.g., Becker et al, 2014;Beghein et al, 2014Beghein et al, , 2018Semple & Lenardic, 2018;VanderBeek & Toomey, 2017;Zheng et...…”

“…It is important to correctly assess the uncertainties of such plate velocities for application to many tectonic and geodynamic problems. These problems include, but are not limited to, the estimation of velocities (and associated uncertainties) of the migration of trenches (Faccenna et al, 2007;Schellart et al, 2008), resolving the motion of ultraslow-moving plates such as Eurasia and Antarctica (Zheng et al, 2014), resolving motion between groups of hot spots (Wang et al, 2017), resolving motion of hot spots relative to the spin axis (e.g., Morgan, 1981;Gordon & Cape, 1981;Besse & Courtillot, 1991;Petronotis et al, 1994;Tarduno & Cottrell, 1997;Torsvik et al, 2002;Zheng et al, 2018), and unraveling the origins of upper mantle anisotropy (e.g., Becker et al, 2014;Beghein et al, 2014Beghein et al, , 2018Semple & Lenardic, 2018;VanderBeek & Toomey, 2017;Zheng et al, 2014). The uncertainties of such velocities are in many cases propagated from the uncertainties in hot spot trends.…”