NZ Herald
  • Home
  • Latest news
  • Herald NOW
  • Video
  • New Zealand
  • Sport
  • World
  • Business
  • Entertainment
  • Podcasts
  • Quizzes
  • Opinion
  • Lifestyle
  • Travel
  • Viva
  • Weather

Subscriptions

  • Herald Premium
  • Viva Premium
  • The Listener
  • BusinessDesk

Sections

  • Latest news
  • New Zealand
    • All New Zealand
    • Crime
    • Politics
    • Education
    • Open Justice
    • Scam Update
  • Herald NOW
  • On The Up
  • World
    • All World
    • Australia
    • Asia
    • UK
    • United States
    • Middle East
    • Europe
    • Pacific
  • Business
    • All Business
    • MarketsSharesCurrencyCommoditiesStock TakesCrypto
    • Markets with Madison
    • Media Insider
    • Business analysis
    • Personal financeKiwiSaverInterest ratesTaxInvestment
    • EconomyInflationGDPOfficial cash rateEmployment
    • Small business
    • Business reportsMood of the BoardroomProject AucklandSustainable business and financeCapital markets reportAgribusiness reportInfrastructure reportDynamic business
    • Deloitte Top 200 Awards
    • CompaniesAged CareAgribusinessAirlinesBanking and financeConstructionEnergyFreight and logisticsHealthcareManufacturingMedia and MarketingRetailTelecommunicationsTourism
  • Opinion
    • All Opinion
    • Analysis
    • Editorials
    • Business analysis
    • Premium opinion
    • Letters to the editor
  • Politics
  • Sport
    • All Sport
    • OlympicsParalympics
    • RugbySuper RugbyNPCAll BlacksBlack FernsRugby sevensSchool rugby
    • CricketBlack CapsWhite Ferns
    • Racing
    • NetballSilver Ferns
    • LeagueWarriorsNRL
    • FootballWellington PhoenixAuckland FCAll WhitesFootball FernsEnglish Premier League
    • GolfNZ Open
    • MotorsportFormula 1
    • Boxing
    • UFC
    • BasketballNBABreakersTall BlacksTall Ferns
    • Tennis
    • Cycling
    • Athletics
    • SailingAmerica's CupSailGP
    • Rowing
  • Lifestyle
    • All Lifestyle
    • Viva - Food, fashion & beauty
    • Society Insider
    • Royals
    • Sex & relationships
    • Food & drinkRecipesRecipe collectionsRestaurant reviewsRestaurant bookings
    • Health & wellbeing
    • Fashion & beauty
    • Pets & animals
    • The Selection - Shop the trendsShop fashionShop beautyShop entertainmentShop giftsShop home & living
    • Milford's Investing Place
  • Entertainment
    • All Entertainment
    • TV
    • MoviesMovie reviews
    • MusicMusic reviews
    • BooksBook reviews
    • Culture
    • ReviewsBook reviewsMovie reviewsMusic reviewsRestaurant reviews
  • Travel
    • All Travel
    • News
    • New ZealandNorthlandAucklandWellingtonCanterburyOtago / QueenstownNelson-TasmanBest NZ beaches
    • International travelAustraliaPacific IslandsEuropeUKUSAAfricaAsia
    • Rail holidays
    • Cruise holidays
    • Ski holidays
    • Luxury travel
    • Adventure travel
  • Kāhu Māori news
  • Environment
    • All Environment
    • Our Green Future
  • Talanoa Pacific news
  • Property
    • All Property
    • Property Insider
    • Interest rates tracker
    • Residential property listings
    • Commercial property listings
  • Health
  • Technology
    • All Technology
    • AI
    • Social media
  • Rural
    • All Rural
    • Dairy farming
    • Sheep & beef farming
    • Horticulture
    • Animal health
    • Rural business
    • Rural life
    • Rural technology
    • Opinion
    • Audio & podcasts
  • Weather forecasts
    • All Weather forecasts
    • Kaitaia
    • Whangārei
    • Dargaville
    • Auckland
    • Thames
    • Tauranga
    • Hamilton
    • Whakatāne
    • Rotorua
    • Tokoroa
    • Te Kuiti
    • Taumaranui
    • Taupō
    • Gisborne
    • New Plymouth
    • Napier
    • Hastings
    • Dannevirke
    • Whanganui
    • Palmerston North
    • Levin
    • Paraparaumu
    • Masterton
    • Wellington
    • Motueka
    • Nelson
    • Blenheim
    • Westport
    • Reefton
    • Kaikōura
    • Greymouth
    • Hokitika
    • Christchurch
    • Ashburton
    • Timaru
    • Wānaka
    • Oamaru
    • Queenstown
    • Dunedin
    • Gore
    • Invercargill
  • Meet the journalists
  • Promotions & competitions
  • OneRoof property listings
  • Driven car news

Puzzles & Quizzes

  • Puzzles
    • All Puzzles
    • Sudoku
    • Code Cracker
    • Crosswords
    • Cryptic crossword
    • Wordsearch
  • Quizzes
    • All Quizzes
    • Morning quiz
    • Afternoon quiz
    • Sports quiz

Regions

  • Northland
    • All Northland
    • Far North
    • Kaitaia
    • Kerikeri
    • Kaikohe
    • Bay of Islands
    • Whangarei
    • Dargaville
    • Kaipara
    • Mangawhai
  • Auckland
  • Waikato
    • All Waikato
    • Hamilton
    • Coromandel & Hauraki
    • Matamata & Piako
    • Cambridge
    • Te Awamutu
    • Tokoroa & South Waikato
    • Taupō & Tūrangi
  • Bay of Plenty
    • All Bay of Plenty
    • Katikati
    • Tauranga
    • Mount Maunganui
    • Pāpāmoa
    • Te Puke
    • Whakatāne
  • Rotorua
  • Hawke's Bay
    • All Hawke's Bay
    • Napier
    • Hastings
    • Havelock North
    • Central Hawke's Bay
    • Wairoa
  • Taranaki
    • All Taranaki
    • Stratford
    • New Plymouth
    • Hāwera
  • Manawatū - Whanganui
    • All Manawatū - Whanganui
    • Whanganui
    • Palmerston North
    • Manawatū
    • Tararua
    • Horowhenua
  • Wellington
    • All Wellington
    • Kapiti
    • Wairarapa
    • Upper Hutt
    • Lower Hutt
  • Nelson & Tasman
    • All Nelson & Tasman
    • Motueka
    • Nelson
    • Tasman
  • Marlborough
  • West Coast
  • Canterbury
    • All Canterbury
    • Kaikōura
    • Christchurch
    • Ashburton
    • Timaru
  • Otago
    • All Otago
    • Oamaru
    • Dunedin
    • Balclutha
    • Alexandra
    • Queenstown
    • Wanaka
  • Southland
    • All Southland
    • Invercargill
    • Gore
    • Stewart Island
  • Gisborne

Media

  • Video
    • All Video
    • NZ news video
    • Herald NOW
    • Business news video
    • Politics news video
    • Sport video
    • World news video
    • Lifestyle video
    • Entertainment video
    • Travel video
    • Markets with Madison
    • Kea Kids news
  • Podcasts
    • All Podcasts
    • The Front Page
    • On the Tiles
    • Ask me Anything
    • The Little Things
  • Cartoons
  • Photo galleries
  • Today's Paper - E-editions
  • Photo sales
  • Classifieds

NZME Network

  • Advertise with NZME
  • OneRoof
  • Driven Car Guide
  • BusinessDesk
  • Newstalk ZB
  • Sunlive
  • ZM
  • The Hits
  • Coast
  • Radio Hauraki
  • The Alternative Commentary Collective
  • Gold
  • Flava
  • iHeart Radio
  • Hokonui
  • Radio Wanaka
  • iHeartCountry New Zealand
  • Restaurant Hub
  • NZME Events

SubscribeSign In

Advertisement
Advertise with NZME.
Home / New Zealand

NZ's ancient kauri yields major scientific discovery

NZ Herald
18 Feb, 2021 08:35 PM5 mins to read

Subscribe to listen

Access to Herald Premium articles require a Premium subscription. Subscribe now to listen.
Already a subscriber?  Sign in here

Listening to articles is free for open-access content—explore other articles or learn more about text-to-speech.
‌
Save

    Share this article

The trunk of an ancient kauri tree from Ngāwhā, Northland. Swamp kauri has revealed more about a mysterious event 42,000 years ago. Photo / Nelson Parker

The trunk of an ancient kauri tree from Ngāwhā, Northland. Swamp kauri has revealed more about a mysterious event 42,000 years ago. Photo / Nelson Parker

Secrets hidden within ancient swamp kauri have revealed a temporary breakdown of Earth's magnetic field 42,000 years ago, prompting global environmental change and mass extinctions.

This dramatic turning point in Earth's history was triggered by a reversal of Earth's magnetic poles and changing solar winds.

"For the first time ever, we have been able to precisely date the timing and environmental impacts of the last magnetic pole switch," said Professor Chris Turney, a co-lead author of a new study just published in major journal Science.

The episode has now been dubbed the "Adams Transitional Geomagnetic Event", or "Adams Event" for short - a tribute to science fiction writer Douglas Adams, who wrote in The Hitchhikers Guide to the Galaxy that "42" was the answer to life, the universe, and everything.

The findings were made possible with ancient New Zealand kauri trees, which have been preserved in sediments for more than 40,000 years.

Advertisement
Advertise with NZME.
Advertisement
Advertise with NZME.

Using the ancient Northland trees, Turney, of the University of New South Wales, and his Kiwi and Australian colleagues were able measure, and date, a spike in atmospheric radiocarbon levels caused by the collapse of Earth's magnetic field.

Cross-sections from several swamp kauri in Niwa's archive were analysed by Dr Andrew Lorrey to determine their age.

"These kauri trees also lived during the time period leading into the Adams Event and provide a baseline of normal radiocarbon levels prior to the unprecedented rise associated with the Adams Event," said Lorrey, a principal scientist at Niwa.

Advertisement
Advertise with NZME.

Using radiocarbon dating, the team tracked the changes in radiocarbon levels during the magnetic pole reversal.

Sequential blocks of wood consisting of 40 annual rings were extracted from four ancient kauri logs and dated by a process called high-precision liquid scintillation counting.

Professor Alan Hogg, director of the University of Waikato Radiocarbon Dating Laboratory, said this technique provided the highest possible accuracy for samples of this age.

The kauri radiocarbon data was charted alongside annual tree ring growth data, which acted as an accurate, internal timestamp.

While scientists already knew the magnetic poles temporarily flipped around 41-42,000 years ago - something known as the Laschamps Excursion - they didn't know exactly how it impacted life on Earth - if at all.

As we know it today, the magnetic north pole doesn't have a fixed location.

It usually wobbles close to the North Pole - the northern-most point of Earth's axis - over time due to dynamic movements within the Earth's core, just like the magnetic south pole.

Sometimes, for reasons that aren't clear, the magnetic pole movements are drastic.

Around 41,000 to 42,000 years ago the north and south pole swapped places entirely.

"The Laschamps Excursion was the last time the magnetic poles flipped," Turney said.

Advertisement
Advertise with NZME.

"They swapped places for about 800 years before changing their minds and swapping back again."

Until now, scientific research has focused on changes that happened while the magnetic poles were reversed, when the magnetic field was weakened to about 28 per cent of its present-day strength.

But according to this new research, the most dramatic part was the lead-up to the reversal, when the poles were migrating across the Earth.

"Earth's magnetic field dropped to only 0-6 per cent strength during the Adams Event," Turney said.

"We essentially had no magnetic field at all - our cosmic radiation shield was totally gone."

In the study, the researchers were able to detail how Earth's atmosphere changed over the period via the kauri tree-ring radiocarbon data and other data aligned to it.

Advertisement
Advertise with NZME.

They used the newly created kauri radiocarbon timescale and other records from sites across the Pacific with global climate modelling to tie large shifts in major wind belts, tropical climate and glacier activity back to the Adams Event.

One of their first clues was that megafauna across mainland Australia and Tasmania went through simultaneous extinctions 42,000 years ago.

The paper suggested that the Adams Event could explain a lot of other evolutionary mysteries, like the extinction of Neanderthals and the sudden widespread appearance of figurative art in caves around the world.

These findings come two years after a particularly important ancient kauri tree was uncovered at Ngāwhā, Northland.

The massive tree - with a trunk spanning over two and a half metres - was alive during the Laschamps.

"Like other entombed kauri logs, the wood of the Ngāwhā tree is so well preserved that the bark is still attached," said Dr Jonathan Palmer, of the University of New South Wales.

Advertisement
Advertise with NZME.

This new ancient kauri timescale has helped to reveal what happened during a dramatic period in Earth's history. The team were able to reconstruct a chain of environmental and extinction events using climate modelling and the kauri records.

"The more we looked at the data, the more everything pointed to 42," Turney said.

"It was uncanny. Douglas Adams was clearly on to something, after all."

Save

    Share this article

Latest from New Zealand

New Zealand

Far North homes without power after severe gales

New Zealand

Man hides out in bush for 5 months after slicing victim with machete over $20

New Zealand

Measles spreads beyond Wairarapa, 6 locations of interest in Feilding


Sponsored

Solar bat monitors uncover secrets of Auckland’s night sky

Advertisement
Advertise with NZME.

Latest from New Zealand

Far North homes without power after severe gales
New Zealand

Far North homes without power after severe gales

More than 170 customers south of Cape Rēinga are still without power.

17 Jul 08:26 AM
Man hides out in bush for 5 months after slicing victim with machete over $20
New Zealand

Man hides out in bush for 5 months after slicing victim with machete over $20

17 Jul 08:00 AM
Measles spreads beyond Wairarapa, 6 locations of interest in Feilding
New Zealand

Measles spreads beyond Wairarapa, 6 locations of interest in Feilding

17 Jul 07:43 AM


Solar bat monitors uncover secrets of Auckland’s night sky
Sponsored

Solar bat monitors uncover secrets of Auckland’s night sky

06 Jul 09:47 PM
NZ Herald
  • About NZ Herald
  • Meet the journalists
  • Newsletters
  • Classifieds
  • Help & support
  • Contact us
  • House rules
  • Privacy Policy
  • Terms of use
  • Competition terms & conditions
  • Our use of AI
Subscriber Services
  • NZ Herald e-editions
  • Daily puzzles & quizzes
  • Manage your digital subscription
  • Manage your print subscription
  • Subscribe to the NZ Herald newspaper
  • Subscribe to Herald Premium
  • Gift a subscription
  • Subscriber FAQs
  • Subscription terms & conditions
  • Promotions and subscriber benefits
NZME Network
  • The New Zealand Herald
  • The Northland Age
  • The Northern Advocate
  • Waikato Herald
  • Bay of Plenty Times
  • Rotorua Daily Post
  • Hawke's Bay Today
  • Whanganui Chronicle
  • Viva
  • NZ Listener
  • Newstalk ZB
  • BusinessDesk
  • OneRoof
  • Driven Car Guide
  • iHeart Radio
  • Restaurant Hub
NZME
  • About NZME
  • NZME careers
  • Advertise with NZME
  • Digital self-service advertising
  • Book your classified ad
  • Photo sales
  • NZME Events
  • © Copyright 2025 NZME Publishing Limited
TOP