Pillans, B. 1990 Late Quaternary marine terraces, south Taranaki-Wanganui. Scale 1:100,000. Lower Hutt: New Zealand Geological Survey. Miscellaneous series map / New Zealand Geological Survey 18 1 fold. map + 1 booklet
Abstract: Twelve marine terraces are named and described from the south Taranaki- Wanganui coastal plain. From oldest to youngest they are Marorau, Piri, Ball, Rangitatau, Ararata, Braemore, Brunswick, Ngarino, Rapanui, Inaha, Hauriri, and Rakaupiko. The terraces are dated using a combination of fission-track dating of one rhyolitic tephra, amino acid racemization dating of wood, and radiocarbon dating of wood. Strandline ages for the terraces, which range from nearly 700 000 to 60 000 years, are estimated using the dates and a tectonic model incorporating shore-normal tilting. The five oldest terraces are assigned a Castlecliffian age; the younger terraces are of Haweran age. Uplift rates vary between c. 0.2 mm/year and 0.7 mm/year, generally increasing inland from the coast. The pattern of uplift, as defined by terrace strandline heights, depicts a southward-plunging anticline, named the Whangamomona Anticline, which strikes NNE. Tilt rates on the western limb of the Whangamomona Anticline average c. 7 nanrad/year in a shore-parallel direction. Terrace strandlines are vertically offset by up to 50 m across several active faults. One of these, the Nukumaru Fault Zone has an average rate of relative vertical movement of 0.08 mm/year over the last 2 million years.