Forced Subduction Initiation at Passive Continental Margins: Velocity‐Driven Versus Stress‐Driven

Abstract

Subduction initiation (SI) at passive continental margin plays a key role in the Wilson cycle of plate tectonics; however, the long‐lived, stable Atlantic‐type margin challenges this hypothesis. The spontaneous SI at passive margin is difficult, which could be instead induced by far‐field tectonic forces. Previous analog and numerical models are generally conducted with constant convergent velocity, which may lead to extremely large boundary force in order for SI. In this study, we focus on numerical models with constant convergent force/stress to investigate the conditions for SI at typical passive margin without any type of prescribed weak zones. The result indicates that the SI at young passive margins with thin oceanic lithosphere is much easier than that at old margins. It reveals the dynamics of multiple newly formed subduction zones in the young oceanic plates of Southeast Asia and Southwest Pacific, but generally no SI for the old Atlantic‐type passive margin.

Dynamic Evolution of Induced Subduction Through the Inversion of Spreading Ridges

“…Besides, the estimated plate tectonic forces of ridge push and slab pull based on analytical force balance are typically in the range of 10 12 –10 13 N/m (Harper, 1975; Schellart, 2004; Turcotte & Schubert, 2014). Thus, these estimated forces constrain our calculation and indicate that subduction initiation along young extinct spreading ridges (e.g., cooling ages of 0, 5 and 10 Myr) is more likely in nature (Figure 8b; Zhong & Li, 2019).…”

Subduction Initiation During Collision‐Induced Subduction Transference: Numerical Modeling and Implications for the Tethyan Evolution

“…These models indicate that the SI at passive continental margin is not easy, which generally requires special conditions, for example, (1) a thin, weak, and very buoyant continental lithosphere (e.g., Nikolaeva et al, ; Marques et al, , ; Rey et al, ); (2) a prescribed weak transition zone between the continental and oceanic plates (e.g., Baes et al, ; Toth & Gurnis, ); (3) driven by downward mantle flow (e.g., Baes & Sobolev, ); or (4) driven by a boundary stress/force (e.g., Zhong & Li, ). On the other hand, the natural examples of Atlantic and Indian passive margins, neighboring to relatively old oceanic lithospheres, are generally stable and difficult for SI (Cloetingh et al, ; Mueller & Phillips, ; Niu et al, ; Stern & Gerya, ; Zhong & Li, ). Thus, it indicates that the collision‐induced subduction transference during Tethyan evolution should not be so easy, because the multiple Tethyan Oceans generally have an old and thick lithosphere at the passive margin (Müller et al, ; Stampfli & Borel, ; Stampfli et al, ).…”

“…Notably, a "trench jump" after collision is predicted in some of the models (Tetreault & Buiter, 2012;Vogt & Gerya, 2014;Yang et al, 2018), which is however caused by the detachment of weak and buoyant crust of the accreting terrane, rather than initiating a new subduction zone in the neighboring oceanic plate. Another type of model focuses on the SI at passive continental margins, which only deal with two plates and a transition between them (e.g., Baes & Sobolev, 2017;Nikolaeva et al, 2011;Rey et al, 2014;Toth & Gurnis, 1998;Ulvrova et al, 2019;Zhong & Li, 2019). These models indicate that the SI at passive continental margin is not easy, which generally requires special conditions, for example, (1) a thin, weak, and very buoyant continental lithosphere (e.g., Nikolaeva et al, 2011;Marques et al, 2013Marques et al, , 2014Rey et al, 2014); (2) a prescribed weak transition zone between the continental and oceanic plates (e.g., Baes et al, 2011;Toth & Gurnis, 1998); (3) driven by downward mantle flow (e.g., Baes & Sobolev, 2017); or (4) driven by a boundary stress/force (e.g., Zhong & Li, 2019).…”

“…Another type of model focuses on the SI at passive continental margins, which only deal with two plates and a transition between them (e.g., Baes & Sobolev, 2017;Nikolaeva et al, 2011;Rey et al, 2014;Toth & Gurnis, 1998;Ulvrova et al, 2019;Zhong & Li, 2019). These models indicate that the SI at passive continental margin is not easy, which generally requires special conditions, for example, (1) a thin, weak, and very buoyant continental lithosphere (e.g., Nikolaeva et al, 2011;Marques et al, 2013Marques et al, , 2014Rey et al, 2014); (2) a prescribed weak transition zone between the continental and oceanic plates (e.g., Baes et al, 2011;Toth & Gurnis, 1998); (3) driven by downward mantle flow (e.g., Baes & Sobolev, 2017); or (4) driven by a boundary stress/force (e.g., Zhong & Li, 2019). On the other hand, the natural examples of Atlantic and Indian passive margins, neighboring to relatively old oceanic lithospheres, are generally stable and difficult for SI (Cloetingh et al, 1989;Mueller & Phillips, 1991;Niu et al, 2003;Zhong & Li, 2019).…”

Reviewing subduction initiation and the origin of plate tectonics: What do we learn from present-day Earth?

“… Conversion of oceanic transform faults/fracture zones: (Uyeda and Ben‐Avraham, 1972; Casey and Dewey, 1984; Toth and Gurnis, 1998; Doin and Henry, 2001; Hall et al, 2003; Gurnis et al, 2004; Baes et al, 2011; Maffione et al, 2017; Guilmette et al, 2018; Zhong and Li, 2020); Inverse at (extinct) spreading ridges (Gurnis et al, 2004; Duretz et al, 2016; Keenan et al, 2016) or detachment faults (van Hinsbergen et al, 2015; Maffione et al, 2015); Inverse at COB (Zhong and Li, 2019); Episodic subduction (Crameri et al, 2020). ii) Externally driven forcing with self‐nucleated shear zone Plate rupture within an oceanic plate under compression forcing (McKenzie, 1977; Cloetingh et al, 1989; Shemenda, 1992; Thielmann amd Kaus, 2012; Zhong and Li, 2019; Crameri et al, 2020); Plate reorganization with sedimentary loading (Erickson and Arkani‐Hamed, 1993); Compression forcing with various localization mechanisms, including shear heating (Crameri and Kaus, 2010; Thielmann and Kaus, 2012) and grain‐size reduction (Bercovici and Ricard, 2005, 2013, 2014; Rozel et al, 2011); Plate rupture induced by plate acceleration (Agard et al, 2007); Subduction zone transference/trench jump (Mitchell, 1984; Stern, 2004; Tetreault and Buiter, 2012; Vogt and Gerya, 2014; Wan B et al, 2019; Wu et al, 2020); Subduction polarity reversal (Mitchell, 1984; Cooper and Taylor, 1985; Pysklywec, 2001; Stern, 2004; Faccenda et al, 2008; von Hagke et al, 2016; Crameri et al, 2020); Conversion of passive margin to subduction zone with suction force imposed at bottom boundary (Baes and Sobolev, 2017);…”