Kaingaroa 'space rock' reminds us to be curious

Red 'Space rock', alongside a 25kg weight - for perspective - and another of Urlich's many interesting finds. Photo/Supplied

While working at his farm in Kaingaroa, a local man discovered an unusual rock he'd never seen before.

Tony Ulrich said the rock appeared quite significant and heavy-looking for its size, estimating it to weigh around 26.5kg.

Urlich found the rock near what he described as a crater, which measured nearly 40 metres across and the same distance down into the earth.

Naturally, he wondered whether his discovery could be a meteorite.

After receiving his photos, the Northland Age contacted GNS Science to learn whether that could be the case.

Nick Mortimer of GNS Science said the question was perhaps the most common one people asked of geologists like himself.

"It's great that people are out there looking around and noticing unusual things," Mortimer said.

"It's important to remember that rocks and fossils are as much a part of the natural environment of Aotearoa New Zealand as plants and animals.

"In fact, it is rocks and geology that led us to discover the submerged continent of Te Riu-a-Māui/Zealandia.

"Like plants and animals, rocks are objects of wonder and beauty.

"They also tell stories - but you don't need to know any geology or science to appreciate them."

Indeed, Urlich has not studied geology and said his interest in rocks was a relatively recent development.

"I did some rock walling at home, and got rocks from various quarries to make a fish pond," Urlich said.

"And I've picked up other unusual ones on the beach.

"They just fascinate me."

In an informal assessment of Urlich's find, which he called his 'space rock', Mortimer consulted geological maps of the Kaitaia area.

"The area where the rock was found is soft grey and blue-grey mudstone," Mortimer said.

"So, yes, the colour and size of the rock do mark it as being out of place - well done to him for recognising this.

"However, it is just the sort of rock that could be found in Maungataniwha Range to the south."

GNS Science's Nick Mortimer consulted this geological map of the Kaitaia area and said the colour and size of the rock marked it as being out of place in Kaingaroa. Photo/Supplied

Mortimer said he couldn't say how the rock could have gotten to where it was found, but a local explanation was likely - it could have been carried by a person or stream.

"Or maybe it's a new occurrence for the area and, one day, geologists will have to change the map."

Mortimer said it was difficult to make a definite identification without seeing the rock in person, but he thought it was probably not scientifically significant.

"Sadly, in all my time as a geologist at GNS Science I have always had to answer 'no' to the meteorite question."

Mortimer said he thought the proximity to what Urlich believed was a crater was coincidental, although "meteorites do turn up from time to time".

And could there be anything more exciting than such a possibility?

Mortimer said he still remembered the first geological sample he collected as an 8-year-old in England.

"It was an ammonite, one of those spiral-shaped fossils," he said.

"Collecting rocks and understanding about the Earth can certainly inspire children into science.

"For me, that childhood hobby eventually turned into a professional career."

Mortimer shared the reminder that rocks were everywhere, even if you couldn't see them.

"Solid rock is only ever a few tens of metres under your feet, under forests, under farms, under cities, underwater."

Mortimer explained the best places to enjoy recreational geology was on river banks and beaches.

That's because that's where nature often delivered a diversity of treasures, cleaned of rust and clay and looked their best thanks to the water.

As for 'space rock', Mortimer said he thought it was red argillite (a recrystallised mudstone) or red chert (silica rock).

Despite the anticlimactic outcome, Urlich's enthusiasm remained.

"The north was definitely hit by something 40,000 years ago," Urlich said.

"I'll dig out the middle of that crater one day."