New Zealand Primary Site

The New Zealand primary site exhibits a wide range of fault slip and volcanic phenomena with significant variation along-strike in a small, compact setting. Excellent exhumed exposures of arc crust and accretionary prism, a zone of active subduction initiation, and significant new government investments in onshore and offshore scientific infrastructure make New Zealand an exciting site for GeoPRISMS research. From north to south, the New Zealand primary site includes the Puysegur Ridge (subduction initiation), Puysegur Trench (subduction), Fiordland (exhumed arc crust), Hikurangi Trench (subduction), the Taupo Volcanic Zone (arc and rift volcanism), the southern Kermadec Arc (subduction), and the Havre Trough (back-arc rifting).

From the Science Plan

Examples of outstanding research questions for the New Zealand primary site include:

  • What are the geological, geochemical, and geophysical responses to subduction initiation and early arc evolution and how to they affect subduction zone formation?
  • What controls the along-strike transition from a locked subduction interface (southern Hikurangi) to a largely creeping interface (northern Hikurangi)? What controls the spatial limits of the seismogenic zone and the location and character of slow slip events?
  • How to Quaternary eustacy, structural deformation, and climate change influence sediment dispersal and sequence architecture in forearc basins?
  • What are the magma transport pathways through the crust, and respective contributions of subducted sediments and crustal assimilation along- and across-strike of the arc?
  • How do rifting and spreading, and the spatial and temporal variation of magmatism, relate to the nature of slab-derived fluid-to-melt and the rheology of the mantle wedge?

Further information about these topics, a summary of existing datasets and infrastructure investments in New Zealand, and critical research efforts for GeoPRISMS studies can be found in Section 2.4 of the GeoPRISMS Implementation Plan.