Abstract
In a recent paper Booden et al. (2011) present new geochemical and petrological data of Early Miocene volcanics from the Northland region (Northland volcanic belt) in New Zealand, and interpret these data to support a particular regional tectonic model. This tectonic model involves Early Miocene westward subduction of Cretaceous Pacific oceanic lithosphere below the Northland volcanic belt and the authors interpret the volcanic belt as a continental magmatic arc. Although the new data are not in disagreement with such a tectonic model, they provide more support for an alternative interpretation that involves a northeast-dipping subduction zone. Furthermore, geometric and plate kinematic data show that the west-dipping subduction model is unviable, geological and geophysical data contradict the model, while geodynamic arguments indicate that the model is implausible. Here it will be shown that a subduction model, involving a northeast-dipping southwestward retreating slab (made of the Late Cretaceous-Paleocene South Loyalty backarc basin lithosphere) that subsequently detaches, is in agreement with the local geology, geophysics and geochemistry, is geometrically, kinematically and geodynamically viable, and fits within the regional Southwest Pacific tectonic framework.
Original language | English |
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Pages (from-to) | 112-117 |
Number of pages | 6 |
Journal | Journal of Volcanology and Geothermal research |
Volume | 211-212 |
DOIs | |
Publication status | Published - 15 Jan 2012 |
Keywords
- Arc magmatism
- Decompression melting
- Mantle flow
- Mantle wedge
- New Zealand
- Northland
- Northland Allochthon
- Obduction
- Rollback
- Slab detachment
- South Fiji Basin
- Southwest Pacific
- Subduction