The subduction initiation stage of the Wilson cycle

Abstract

In the Wilson cycle, there is a change from an opening to a closing ocean when subduction begins. Subduction initiation is commonly identified as a major problem in plate tectonics and is said to be nowhere observable, yet there are many young subduction zones at the west Pacific margins and in eastern Indonesia. Few studies have considered these examples. Banda subduction developed by the eastwards propagation of the Java trench into an oceanic embayment by tearing along a former ocean-continent boundary. The earlier subducted slab provided the driving force to drag down unsubducted oceanic lithosphere. Although this process may be common, it does not account for young subduction zones near Sulawesi at different stages of development. Subduction began there at the edges of ocean basins, not at former spreading centres or transforms. It initiated at a point where there were major differences in elevation between the ocean floor and the adjacent hot, weak and thickened arc/continental crust. The age of the ocean crust appears to be unimportant. A close relationship with extension is marked by the dramatic elevation of land, the exhumation of deep crust and the spectacular subsidence of basins, raising questions about the time required to move from no subduction to active subduction, and how initiation can be identified in the geological record.

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

“…On the other hand, the geological records for SI are even more complex (Guilmette et al, ; Hall, ; Pandey et al, ; Parlak et al, ; Patriat et al, ; Searle, ; Stern, ; Stern et al, ). The emplacement of magmatic rock is generally later, by several million years, than the exact time of SI (Arculus et al, ; Hall, ; Shervais et al, ). Thus, the timing of SI may be delayed according to the magmatic records.…”

“…Thus, the timing of collision is a bit varied among different studies (Aitchison et al, 2007;DeCelles et al, 2014;Najman et al, 2010;Searle, 2019;Yin & Harrison, 2000;Zhu et al, 2015). On the other hand, the geological records for SI are even more complex (Guilmette et al, 2018;Hall, 2018;Pandey et al, 2019;Parlak et al, 2019;Patriat et al, 2019;Searle, 2019;Stern, 2004;Stern et al, 2012). The emplacement of magmatic rock is generally later, by several million years, than the exact time of SI (Arculus et al, 2019;Hall, 2018;Shervais et al, 2019).…”

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

“…The Celebes Sea is a relatively old oceanic basin in this region (Figure b), with two subduction zones on both the north and south margins (Bird, ; Hall, ). In the south, the North Sulawesi Trench initiates around 9 Myr ago (Hall, ; Nichols & Hall, ). In the north, the Cotobato trench is even younger; however, it may not be caused by the convergence (Hall, ).…”

“…Since the spontaneous SI is generally difficult on the present Earth, the SI could also be induced (Gurnis et al, 2004;Hall, 2018;Leng & Gurnis, 2015;McKenzie, 1977 ;Mueller & Phillips, 1991;Toth & Gurnis, 1998). Among many induced SI models, the simplest one is driven by the far-field forces, for example, compression (Faccenna et al, 1999).…”

Subduction Duration and Slab Dip

“…Although diagnostic of geodynamic processes, this important parameter has been ignored in the decades because of perceived difficulties and uncertainties constraining the duration of subduction. Given the past demonstration that it is a key control on the geodynamics of subduction combined with a resurgence of observational work on subduction initiation (Arculus et al, ; Gurnis et al, ; Hall, ), returning duration of subduction to the multivariate analysis of subduction parameters is warranted.…”