A revision of mid-late Holocene marine terrace distribution and chronology at the Pakarae River mouth, North Island, New Zealand

A suite of seven marine terraces at the Pakarae River mouth, New Zealand, provide evidence for the highest Holocene coastal uplift rates adjacent to the Hikurangi Subduction Zone. New elevation, coverbed stratigraphy, and age data allow for a timely revision of the distribution, nomenclature, and chronology of these terraces. Terrace correlation primarily is based on the elevation of the wave-cut strath. Terrace preservation either side of the river is more equal than previously proposed. The age of a abandonment of each terrace is c. 7 ka (T1), 4.3 ka (T2), 3.5 ka (T3), 2.89 ka (T4), 1.6 ka (T5), 0.91 ka (T6), and < 0.91 ka (T7). The average Holocene tectonic uplift rate at Pakarac is 3.2 +/- 0.8 mm/yr. The abandonment of each terrace, from T2 to T7, probably took place after a discrete uplift event. The average time interval between these events is 850 +/- 450 yr and the average uplift magnitude is 2.7 +/- 1.1 m per event. We infer that uplift has been accommodated by slip on an offshore reverse fault. Normal slip on the Pakarae Fault, at right angles to the margin, occurs at a comparatively slower rate and has probably made little contribution to coastal uplift.