Structure and interpretation of the Alpine schists in Copland and Cook River Valleys, South Island, New Zealand

Copland and Cook River Valleys provide a cross‐section through the 25 km wide, pum‐pellyite‐actinolite to amphibolite facies Alpine schists along the Indian/Pacific plates boundary in South Island, New Zealand. Five phases of deformation are reported: D 1 , possible soft‐sediment folding; D 2 , syn‐first metamorphic isoclinal folds; D 3 , syn‐second metamorphic regional folds; D., local upright folds; D 5 , faulting. The D 3 structures include vertically and laterally anastomosing late D3 domains of intense transposition (Paringa domains). The D3 structures formed during mid Tertiary to Late Miocene times in response to broadly. distributed dextral transpressive strain along the Indian/Pacific plates' boundary. This strain was localised later to the Alpine Fault. The D3 structural style changes south of Moeraki Valley, and reflects the change in dip of the plate boundary, from steeply east‐dipping in the study area, to shallowly east‐dipping south of Moeraki Valley.