Terrane affiliation and terrane boundaries of Mesozoic accretionary complexes, northeastern North Island, New Zealand: Some implications from recycled elastics

Abstract

In the late Mesozoic Waioeka petrofacies in northeastern North Island, New Zealand, sandstone pebbles differ significantly in petrography from their enclosing sandy conglomerate matrix, and yield contrasting provenance signatures. The compositional contrast demonstrates the extrabasinal origin of most of the analysed clasts. Differences in clast provenance have been used to review boundaries and the terrane affiliation to the neighbouring Torlesse and Waipapa composite terranes.

A previously postulated Cretaceous large‐scale dextral strike‐slip displacement of eastern North Island along the Wellington‐Mohaka‐Whakatane Fault is supported by these data. The timing for this movement can be further bracketed between c. 98 and 85 Ma. The Waioeka and Omaio petrofacies, formerly attributed to the Torlesse terranes as the Waioeka Subterrane, are reinterpreted to constitute a separate terrane (Waioeka‐Mata River Terrane). However, the westernmost portion of the former Waioeka Subterrane, west of the Wellington‐Mohaka‐Whakatane Fault, is considered to be part of the Waipapa composite terrane.

Keywords:

• New Zealand
• accretionary terranes
• eastern North Island
• petrography
• sandstone pebbles
• dextral displacement