Foraminiferal record of Holocene sea level

Collaborators: Roland Gehrels (University of Plymouth, U.K.); Kate Southall (Trinity College, Dublin); Ursula Cochran (GNS, Lower Hutt)

Foraminiferal distribution in high tidal salt meadows and salt marshes is strongly zoned with respect to tidal elevation. This zonation can be used to estimate (using transfer functions or modern analogue technique) the tidal elevation at which fossil Holocene foraminiferal assemblages once lived. High resolution studies of fossil foraminiferal faunas in cores of salt marsh peat can be used to reconstruct changes in sea level over the last 500-1000 years.

Our pilot study in southern New Zealand indicates 35 cm sea-level rise in the last 130 years. For further studies around New Zealand, we are focussing on the tectonically more stable coastal areas in New Zealand away from the earthquake-prone plate boundary deformation zone.

Study areas

a. South Otago (Pounawea, Catlins Lake) - partly published, 2006; published 2008.
b. Tasmania - field work undertaken, 2006. Gehrels led. Published 2011.
c. Southland (Mokomoko Inlet)- analyses underway, 2006-2015. Gehrels led
d. Eastern Southland (Waikawa Harbour) - completed by PhD, Brigida Figueira, 2012. Part-published 2014.
e. North-west Nelson (West Haven Inlet,and Golden Bay) - completed by PhD, Brigida Figueira, 2012.
f. Subantarctic Islands (Auckland Island) - reconnaissance undertaken, 2004, abandoned.

g. Auckland (Puhinui, Manukau Harbour) published 2012.

h. Coromandel Peninsula (Tairua) analyses and dating complete, awaiting write-up (2015).