New Zealand Journal of Geology & Geophysics abstracts
A revision of mid–late Holocene marine terrace distribution and
chronology at the Pakarae River mouth, North Island, New Zealand
Kate Wilson1*
Kelvin Berryman2
Nicola Litchfield2
Tim Little1
1School of Earth Sciences
Victoria University of Wellington
PO Box 600
Wellington 6140, New Zealand
2GNS Science
PO Box 30368
Lower Hutt 5040, New Zealand
*Present address: GNS Science, PO Box 30368, Lower Hutt
5040, New Zealand.
Abstract 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 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 Pakarae 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.
Keywords marine terraces; Pakarae River; coastal
uplift;
neotectonics
G06007; Online publication date 22 November 2006; Received 15 March
2006; accepted 18 October 2006
New Zealand Journal of Geology & Geophysics, 2006, Vol. 49:
477–489
0028–8306/06/4904–0477 © The Royal Society of New Zealand
2006
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