Tag: Tonga-Kermadec

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SZI Events Tonga-Kermadec

Tonga-Kermadec subduction zone initiation

Schematic tectonic reconstruction of the Tonga-Kermadec SZI event (modified from Whattam et al., 2008). The collision of the Papua New Guinea continental block with the Loyalty-Three Kings trench is suggested to have caused a flip in subduction polarity, initiating the new Tonga-Kermadec subduction zone, possibly exploiting a weakness due to the presence of an old 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).
Schematic tectonic reconstruction of the Tonga-Kermadec SZI event (modified from Whattam et al., 2008). The collision of the Papua New Guinea continental block with the Loyalty-Three Kings trench is suggested to have caused a flip in subduction polarity, initiating the new Tonga-Kermadec subduction zone, possibly exploiting a weakness due to the presence of an old 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).

The Tonga-Kermadec subduction zone’s initiation is a debated topic, with suggestions ranging from 30 to 100 Ma. Collision events, back-arc magmatism, and tectonic models contribute to understanding this geological phenomenon. Seismic data indicate a deep slab anomaly, reflecting complex geological processes in the region over millions of years.