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Excavation underway at Coralie Bay

Excavation underway at Coralie Bay

by Louise Furey
Sun, 8 Feb 2015

Day one on site is always slow to start as we work out the best strategy for excavation and where to excavate to gain maximum information about the site and its contents.

Finding signs of human habitation

The toe of the dune at Coralie Bay is eroding, exposing a blackened sand layer about 20 cm deep under a similar depth of more recent sand. On the wind-deflated adjacent surface are obsidian and basalt flakes and fire-cracked rocks which have dropped out of the black sand layer.

Behind the eroding face is a large flat area with several large stones visible through the grass. We want to investigate some of this flat area to see what use it was put to, and try to determine the purpose of the stones which do not occur naturally here.

Creating a 3D plan of the landscape

First a geophysical survey was carried out on a 40 x 20 m grid to detect sub-surface anomalies and target where we should excavate. The Leica laser scanner was then used to make a 3D scan of the landscape. This is another tool used to gather information about surface irregularities and subtle changes in contour. Then we were ready to begin the dirty work.

Resistivity machine used on a regularly spaced grid to detect anomalies of high and low resistivity under the ground surface.

Furey, Louise. 2015.Auckland War Memorial Museum - Tāmaki Paenga Hira.

We collected and bagged each of the flakes on the deflated surface and their locations recorded with the Leica theodolite. This is standard practice for every artefact and sample collected and the data recorded by the machine is then downloaded every evening into GIS. A 5 x 5 m square was laid out, giving students a practical demonstration in how to make right angles using basic geometry: a2 + b2 = c2.

The back-breaking work of excavation

The hardest parts of an excavation are cutting the turf into squares and deturfing, and at the end of the excavation the back filling of the holes with all the deposit taken out. The heat today made deturfing all the more difficult but very satisfying to finally have a 5 x 5 m square of bare sand awaiting excavation at the end of the day.

The unique ID allows each artefact and sample to be tracked through the analysis. Each layer also has a unique ID.

Furey, Louise. 2015.Auckland War Memorial Museum - Tāmaki Paenga Hira.

Progress report

Excavation began slowly as students learned how to hold and use a trowel but confidence increased quickly and progress was made on removing the sand overburden onto the black sand layer which contained flakes and fire cracked rocks (raked out of hangi and discarded).

The dark colour is from charcoal staining of the sand from cooking and heating fires. The rocks visible on the surface

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  • Post by: Louise Furey

    Dr Louise Furey is the E. E. Vaile Curator of Archaeology at Auckland Museum. Louise has been an archaeologist for 35 years and has carried out site assessments and archaeological excavations in the upper North Island. She holds an MA (Hons) and a Doctorate of Science degree from the University of Auckland.

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