Thermochronological evidence of a low-angle, mid-crustal detachment plane beneath the central South Island, New Zealand

Oblique continental convergence and uplift in the Southern Alps, New Zealand is largely accommodated by dextral transpression on the Alpine Fault. However, towards the south of the orogen the Alpine Fault becomes increasingly strike-slip, despite evidence for high exhumation rates in the Pacific plate. Here, we present 41 new apatite and zircon fission-track ages to investigate the role of the southern Alpine Fault in Pacific plate exhumation since the Miocene. Through development of a new, maximum likelihood fission-track age calculation method (to overcome extremely low (< 0.1 ppm) 238U concentrations in apatites) we estimate the width of the fully reset apatite zone (ages