• HOME
  • NEWS
    • BIOENGINEERING
    • SCIENCE NEWS
  • EXPLORE
    • CAREER
      • Companies
      • Jobs
    • EVENTS
    • iGEM
      • News
      • Team
    • PHOTOS
    • VIDEO
    • WIKI
  • BLOG
  • COMMUNITY
    • FACEBOOK
    • FORUM
    • INSTAGRAM
    • TWITTER
  • CONTACT US
Saturday, February 27, 2021
BIOENGINEER.ORG
No Result
View All Result
  • Login
  • HOME
  • NEWS
    • BIOENGINEERING
    • SCIENCE NEWS
  • EXPLORE
    • CAREER
      • Companies
      • Jobs
        • Lecturer
        • PhD Studentship
        • Postdoc
        • Research Assistant
    • EVENTS
    • iGEM
      • News
      • Team
    • PHOTOS
    • VIDEO
    • WIKI
  • BLOG
  • COMMUNITY
    • FACEBOOK
    • FORUM
    • INSTAGRAM
    • TWITTER
  • CONTACT US
  • HOME
  • NEWS
    • BIOENGINEERING
    • SCIENCE NEWS
  • EXPLORE
    • CAREER
      • Companies
      • Jobs
        • Lecturer
        • PhD Studentship
        • Postdoc
        • Research Assistant
    • EVENTS
    • iGEM
      • News
      • Team
    • PHOTOS
    • VIDEO
    • WIKI
  • BLOG
  • COMMUNITY
    • FACEBOOK
    • FORUM
    • INSTAGRAM
    • TWITTER
  • CONTACT US
No Result
View All Result
Bioengineer.org
No Result
View All Result
Home NEWS Science News Biology

42,000-year-old trees allow more accurate analysis of last Earth’s magnetic field reversal

Bioengineer by Bioengineer
February 19, 2021
in Biology
0
Share on FacebookShare on TwitterShare on LinkedinShare on RedditShare on Telegram

Radiocarbon measurements on the remains of 42.000 years old New Zealand kauri trees provide the basis for better calibration of geological archives of this period

IMAGE

Credit: Nelson Parker

The last complete reversal of the Earth’s magnetic field, the so-called Laschamps event, took place 42,000 years ago. Radiocarbon analyses of the remains of kauri trees from New Zealand now make it possible for the first time to precisely time and analyse this event and its associated effects, as well as to calibrate geological archives such as sediment and ice cores from this period. Simulations based on this show that the strong reduction of the magnetic field had considerable effects in the Earth’s atmosphere. This is shown by an international team led by Chris Turney from the Australian University of New South Wales, with the participation of Norbert Nowaczyk from the German Research Centre for Geosciences Potsdam and Florian Adolphi from the Alfred Wegener Institute, in a study that now appears in the journal Science.

The Earth’s magnetic field undergoes permanent fluctuations and occasionally even reversals of polarity occur. Their causes, course and effects are not yet fully understood. Researchers have now investigated the so-called Laschamps event in more detail. It refers to the last complete reversal of the polarity of the Earth’s magnetic field around 42,000 years ago. Not only did the magnetic field change direction, it also dramatically lost strength over a period of several hundred years.

About 42,000 years ago, the magnetic north pole moved south. Within this process, which lasted about 500 years, the magnetic field weakened to between six and zero per cent. During a period of about 500 years, the poles remained reversed, with a field strength that varied below 28 per cent of today’s value, only to reverse again over the course of about 250 years.

This exact chronological classification is now possible by linking different data sets. Firstly, the researchers used results on the Earth’s magnetic field from sediment cores of the Black Sea by Norbert Nowaczyk and his team from 2013, which were matched with Greenland ice cores via climate variation documented at the same time.

Secondly, the exact analysis and dating of the events was only made possible by the radiocarbon (14C) analysis of a sub-fossil kauri tree that grew in the wetlands of Ngawha in northern New Zealand for around 1700 years during the period in question and was subsequently very well preserved in the swamps.

Chris Turney had reported on this finding from about 40,000 years ago during a visit to the German Research Centre for Geosciences in Potsdam (GFZ) a few years ago. “As a geomagnetic scientist, I immediately had a link to the Laschamps event in mind and suggested 14C analyses, which had not yet been done on trees from that time,” says Nowaczyk, who heads the Laboratory for Palaeo- and Rock Magnetism at the GFZ.

The background: With the dwindling of the magnetic field, the Earth is losing an important protective shield against cosmic radiation, at least in part. This is also reflected in increased levels of the radioactive carbon isotope 14C in the trees. The reason for that is the increased formation of 14C in the Earth’s atmosphere during the bombardment of nitrogen by high-energy, electrically charged cosmic particles.

“The sub-fossil kauri trees are an exciting archive of atmospheric composition,” says Florian Adolphi, palaeoclimatologist at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). These trees can live for several thousand years and record annual variations in atmospheric radiocarbon content as they grow, which the research team measured precisely.

“These data improve the calibration curve for radiocarbon dating, allowing more accurate dating of a wide range of climate archives and fossils. They also allow a direct comparison to ice cores: beryllium isotopes measured there show similar variations to the radiocarbon in the trees, as the production of both isotopes in the Earth’s atmosphere depends on the intensity of cosmic rays hitting the Earth,” explains the study’s co-author. He uses this effect to synchronise trees and ice cores with high precision and reduce the uncertainty of comparing the two archives from several thousand years to about 100 years.

To investigate further effects of the weak Earth’s magnetic field on the atmosphere and thus also on the global climate, the researchers carried out simulations of atmospheric chemistry. Among other things, they found a decrease in ozone. “Unfiltered radiation from space was breaking up air particles in the Earth’s atmosphere, separating electrons and emitting light – a process called ionisation,” Turney explains. “The ionised air ‘sizzled’ the ozone layer.” This triggered a wave of changes in the atmosphere, including increased dazzling light shows that we know as the aurora borealis, which at the time may have been observed not only near the poles but across the globe.

It is important to further analyse the effects of the weak magnetic field in this direction in view of current developments, says Nowaczyk. Because the Earth’s magnetic field has already been weakening for about 2000 years. Compared to the first direct measurements 170 years ago, a weakening of nine per cent was observed, in the area of the South Atlantic even thirty per cent. Whether this means that a pole reversal is in the offing for the next one to two thousand years is debatable. However, a collapse of the natural radiation shield would pose a great challenge to our present-day society, which is very much based on electronics.

On the basis of these new possibilities for the chronological classification of the events 42,000 years ago, the main authors of the study put forward even more far-reaching hypotheses about the effects of the Earth’s magnetic field reversal – for example with regard to the extinction of the Neanderthals or the onset of cave paintings. Nowaczyk does not rule out the possibility that there are causal connections here, but considers it rather unlikely.

###

Media Contact
Dr. Norbert Nowaczyk
[email protected]

Related Journal Article

http://dx.doi.org/10.1126/science.abb8677

Tags: ArchaeologyAtmospheric ChemistryAtmospheric ScienceEarth ScienceElectromagneticsGeology/SoilOld WorldPaleontologyPlanets/Moons
Share12Tweet8Share2ShareShareShare2

Related Posts

IMAGE

Predicts the onset of Alzheimer’s Disease (AD) using deep learning-based Splice-AI

February 27, 2021
IMAGE

Cerium sidelines silver to make drug precursor

February 26, 2021

Agents of food-borne zoonoses confirmed to parasitise newly-recorded in Thailand snails

February 26, 2021

Dinosaur species: ‘Everyone’s unique’

February 26, 2021

Leave a Reply Cancel reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

POPULAR NEWS

  • IMAGE

    Terahertz accelerates beyond 5G towards 6G

    638 shares
    Share 255 Tweet 160
  • People living with HIV face premature heart disease and barriers to care

    82 shares
    Share 33 Tweet 21
  • Global analysis suggests COVID-19 is seasonal

    38 shares
    Share 15 Tweet 10
  • HIV: an innovative therapeutic breakthrough to optimize the immune system

    35 shares
    Share 14 Tweet 9

About

We bring you the latest biotechnology news from best research centers and universities around the world. Check our website.

Follow us

Tags

Technology/Engineering/Computer ScienceMedicine/HealthcancerInfectious/Emerging DiseasesEcology/EnvironmentMaterialsCell BiologyClimate ChangeBiologyGeneticsPublic HealthChemistry/Physics/Materials Sciences

Recent Posts

  • Predicts the onset of Alzheimer’s Disease (AD) using deep learning-based Splice-AI
  • When foams collapse (and when they don’t)
  • UTA researcher explores effects of trauma at the cellular, tissue levels of the brain
  • Picture books can boost physical activity for youth with autism
  • Contact Us

© 2019 Bioengineer.org - Biotechnology news by Science Magazine - Scienmag.

No Result
View All Result
  • Homepages
    • Home Page 1
    • Home Page 2
  • News
  • National
  • Business
  • Health
  • Lifestyle
  • Science

© 2019 Bioengineer.org - Biotechnology news by Science Magazine - Scienmag.

Welcome Back!

Login to your account below

Forgotten Password?

Create New Account!

Fill the forms below to register

All fields are required. Log In

Retrieve your password

Please enter your username or email address to reset your password.

Log In