Subduction formation Archives - Page 2 of 3 - Accessible Science Graphics Collection

Schematic tectonic reconstruction of the Ryukyu SZI event (modified from Faccenna et al., 2018). A slab break-off event caused a pause in arc activity. Subduction of the Philippine Sea plate started again along the same margin, initiating the new Ryukyu subduction zone. Shown are the new subduction zone (pink line), other active (solid purple lines) and inactive (dashed purple lines) subduction zones, and spreading ridges (solid red lines).

Ryukyu subduction zone initiation

The Ryukyu SZI event reinitiated subduction of the Philippine Sea plate below the Eurasian plate through episodic subduction at around 6 Ma.

Schematic tectonic reconstruction of the South Sandwich SZI event (modified from Dalziel et al., 2013b). The arrival of the Chile ridge at the South America trench might have triggered a flip in subduction polarity, but the South Sandwich subduction zone is suggested to have initiated as a newly destructive boundary. Shown are the new subduction zone (pink line), other active subduction zones (solid purple lines), spreading ridges (solid red lines), and transform faults (red dashed lines).

South Sandwich subduction zone initiation

The South Sandwich SZI event is estimated to have occurred between 39 and 29 Ma as a new destructive boundary.

Schematic tectonic reconstruction of the Anatolia SZI event (modified from van Hinsbergen et al., 2019a,b). Shown are the new subduction zone (pink line), other active subduction zones (solid purple lines), and transform faults (red dashed lines).

Anatolia subduction zone initiation

The Anatolia subduction zone (or ‘Anatolian Neotethys’) started at around 104 Ma as a consequence of fracture zone inversion.

Oman subduction zone initiation

The Oman subduction zone, together with the Anatolian subduction zone, started at around 104 Ma as a consequence of fracture zone inversion.

Schematic tectonic reconstruction of the New Hebrides-New Britain SZI event (modified from Schellart et al., 2006 and Holm et al., 2016). The collision of the Ontong Java plateau with the trench of the Melanesian subduction zone is suggested to have caused a flip in subduction polarity, initiating the New Hebrides-New Britain subduction zone. Shown are the new subduction zone (pink line) and other active (solid purple lines) and inactive (dashed purple lines) subduction zones.

New Hebrides-New Britain subduction zone initiation

The New Hebrides-New Britain (NHNB) SZI event evolved into the New Hebrides, San Cristobal, and New Britain trenches by subduction polarity reversal at around 10 Ma.

Schematic tectonic reconstruction of the Lesser Antilles SZI event (modified from van Benthem et al., 2013 and Boschman et al., 2014). Subduction of the North and South America plates beneath the Caribbean plate was probably already active earlier on. At 58-39 Ma, subduction jumped eastwards, creating the new Lesser Antilles SZ. Shown are the new subduction zone (pink line), other active (solid purple lines) and inactive (dashed purple lines) subduction zones, and transform faults (red dashed lines).

Lesser Antilles subduction zone initiation

The Lesser Antilles SZI event that formed the present-day Lesser Antilles subduction zone likely occurred between 59–38 Ma and might be an episodic event.

Schematic tectonic reconstruction of the Izu-Bonin-Mariana SZI event (modified from Lallemand, 2016). A plate reorganisation, possibly due to the arrival of the Izanagi ridge at the trench, is suggested to trigger SZI along a pre-existing transform fault in the south, initiating the Izu-Bonin-Mariana subduction zone. The orange circle shows the location of the Oki-Daito plume. Shown are the new subduction zone (pink line), other active (solid purple lines) and inactive (dashed purple lines) subduction zones, spreading ridges (solid red lines), and transform faults (red dashed lines).

Izu-Bonin-Mariana subduction zone initiation

The onset of the Izu-Bonin-Mariana (IBM) subduction zone likely occurred at around 52 Ma likely along a pre-existing fracture zone after a plate reorganisation.

Puysegur trench formation

A schematic highlighting the formation of the Puysegur trench, New Zealand, where subduction zone initiation may be both horizontally and then vertically driven, according to a 4D evolution model of this margin.

Subduction zone initiation types

Illustration of the three types of subduction zone initiation (SZI) events, namely Newly destructive, Episodic subduction, and Polarity reversal.