Research project uses shells to determine timing of Māori settlement

By Marena Mane

The Royal Society Te Apārangi has just awarded a Marsden Fund grant to a research project that uses marine shells to estimate the time of important events and phases in Māori history.

Carbon dating shells from Māori archaeological sites will be used to investigate Māori arrival in Aotearoa, changes in the economy, and changes in material culture. The cross-institutional collaboration will begin in the middle of 2022.

Dr. Gerard O'Regan of Ngāi Tahu, a Māori curator at the Otago Museum and a project collaborator, explains that when things die, they stop absorbing specific carbon isotopes, and the rate of decay of those isotopes can actually identify when anything died.

“Because shells were once alive, we can date when the shellfish died,” he says.

According to O'Regan, this study tackles some of the major challenges with radiocarbon dating, which is a method for determining the age of an object containing organic material that mainly relies on charcoal, which is difficult to come by in Aotearoa.

“On the other hand shells are everywhere … they're very easy to be able to figure out whereabouts in the kind of archaeological layers the shells derived from.”

Another concern, according to O'Regan, is that for the radiocarbon dates to make sense, they must be collaborated and because they utilise a general collaboration system rather than one especially designed for Aotearoa, the results can be erroneous.

“What we're really after is to try to get a really good calculation for New Zealand.”

O'Regan believes that this project will allow him and his team to have a better understanding of when our tūpuna (ancestors) first arrived in Aotearoa, as well as changes over time, resulting in more reliable radiocarbon dates.

“So we aren’t able to say who the tūpuna were but we'll be able to say when they were.”