Cenozoic bending of New Zealand basement terranes and Alpine Fault displacement: A brief review

Abstract

It is now possible to accurately reconstruct late Eocene‐Recent positions of the Australian plate with respect to the Pacific plate. Rates of plate displacement through New Zealand were slow in Eocene‐Oligocene time, and increased rapidly in Miocene time as the pole of rotation migrated southeast. Reconstruction of Maitai Terrane rocks suggests they had a smooth and continuously curved geometry through New Zealand in late Eocene time, which was probably similar to their Late Cretaceous configuration. This analysis implies that most or all Alpine Fault offset occurred after 45 Ma, and suggests about half the Eocene‐Recent plate displacement was partitioned onto the Alpine Fault, and half was accommodated by distributed crustal shear. Estimates of Pliocene and Quaternary Alpine Fault displacement rate suggest the proportion of plate boundary displacement partitioned onto the Alpine Fault may have increased with time, displacement rate, and total displacement.

Keywords:

• Alpine Fault
• Cenozoic
• deformation
• orocline
• structure
• tectonics
• New Zealand
• reconstruction
• bending