A foraminiferal proxy record of 20th century sea-level rise in the Manukau Harbour, New Zealand

作者：Grenfell Hugh R^*; Hayward Bruce W; Nomura Ritsuo; Sabaa Ashwaq T

来源：Marine and Freshwater Research, 2012, 63(4): 370-384.

DOI：10.1071/MF11208

• Late Holocene
• sea-level record
• transfer functions

The present study aimed to extract a sea-level history from northern New Zealand salt-marsh sediments using a foraminiferal proxy, and to extend beyond the longest nearby tide-gauge record. Transects through high-tidal salt marsh at Puhinui, Manukau Harbour, Auckland, New Zealand, indicate a zonation of dominant foraminifera in the following order (with increasing elevation): Ammonia spp.-Elphidium excavatum, Ammotium fragile, Miliammina fusca, Haplo-phragmoides wilberti-Trochammina inflata, Trochamminita salsa-Miliammina obliqua. The transect sample faunas are used as a training set to generate a transfer function for estimating past tidal elevations in two short cores nearby. Heavy metal, Pb-210 and Cs-137 isotope analyses provide age models that indicate 35 cm of sediment accumulation since similar to 1890 AD. The first proxy-based 20th century rates of sea-level rise from New Zealand%26apos;s North Island at 0.28 +/- 0.05 cm year(-1) and 0.33 +/- 0.07 cm year(-1) are estimated. These are faster than the nearby Auckland tide gauge for the same interval (0.17 +/- 0.1 cm year(-1)), but comparable to a similar proxy record from southern New Zealand (0.28 +/- 0.05 cm year(-1)) and to satellite-based observations of global sea-level rise since 1993 (0.31 +/- 0.07 cm year(-1)).

• 出版日期2012