Fossils about 3.5 million years old found in Auckland tunnel dig

From Checkpoint, 5:55 pm on 28 October 2021

Fossils up to 3.5 million years old have been discovered while digging a new tunnel for Auckland's wastewater. 

While digging 35 metres below the earth's surface in Māngere, Watercare's Central Interceptor team stumbled on piles of treasure. 

"All of a sudden these shells started appearing out of the plant and we thought what are these? We weren't thinking we were going to hit anything," Watercares' Central Interceptor director Shayne Cunis told Checkpoint

"Then the geological staff on site said: 'These are really old, about three to four million years old, from the kawa formation." 

Cunis is in charge of building the giant underground wastewater tunnel running from Grey Lynn to Māngere. 

As they dug through a five-metre-thick shell bed layer they unearthed the fossils, with more than 200 different species found. 

"It's evidence of what New Zealand was like from a long time ago, well before people we here, and there was much to learn

So they have brought in experts like Auckland Museum paleontologist Nathan Collins to help.  He has spent hours digging through piles of sediment over the last couple of months. He never dreamed of what they would find. 

"This is possibly a jaw section of a baleen whale, and this is what we think is a sperm whale tooth. This could be one of the oldest ever found in New Zealand. 

"These are great white shark teeth. We've compared them to some of the shark's teeth we have in the museum's collection. From that we can estimate it was probably 3.5 metres long," he told Checkpoint.

Shells, snails, and tiny sea creatures are also on the list. It has given them an insight into life millions of years ago. 

"This one here which is a cone shell, and this big marine snail and this coral, all once lived in warmer waters which are much warmer than they are today."

Senior collection manager at Auckland War Memorial Museum, Rebecca Bray, says the findings triumph their existing fossils. 

"We have one similar collection that was collected in the 1940s from the Waitematā Brewery, when a well was dug. There was about 140 species, but here we've already got about 200 species here onsite with the project still ongoing. 

"And probably about 14 new species at this stage. One of the most significant finds we have is some flax snails, which were previously only known to be about 100,000 years old in the fossil record. But we've got them at about 3.5 million years old, which is a really big extension in fossil time for that species." 

Bray said the artefacts will be housed and cared for at the museum for future generations. 

"We'll also be collecting a subset of fossils for mana whenua, and some fossils for local schools for future education programmes."

One to add to the lists of things to see in Auckland, once lockdown lifts.