African rocks record ancient magnetic field
2010 05 05
By Jonathan Amos | BBCNews.co.uk
Scientists have managed to push back the date for the earliest known presence of a magnetic field on Earth by about 250 million years.
The evidence is seen in tiny iron minerals that are aligned inside ancient dacite rocks from the Barberton mountains in South Africa.
Analysis of the 3.45-billion-year-old minerals indicates the strength the field was much weaker than today.
Earth’s magnetic field protects all life on the planet.
It forms a shield that deflects harmful particles from the Sun around our world, and limits the ability of this "solar wind" to erode our atmosphere.
The new work by Professor John Tarduno, from the University of Rochester, US, and colleagues has been discussed at a major Earth sciences meeting in Vienna, Austria.
"Earth’s magnetic field is important to us," Professor Tarduno told the European Geosciences Union meeting.
"[3.45 billion years ago] is a really critical time because it’s when we start seeing the first tentative signs of life, so perhaps these two things are linked together."
The Rochester team has developed techniques for studying tiny magnetite minerals trapped inside the crystals of volcanic rock.
These minerals orientate themselves with respect to the Earth’s magnetic field in a cooling magma and lock their positions once the temperature in the host rock dips below 580C.
The Barberton samples indicate the nascent field was considerably weaker than today’s protective shield.
Whereas the modern boundary between our planet’s magnetosphere and the solar wind might be located ordinarily at about 10 Earth radii, the ancient boundary would have been much closer - perhaps three to five Earth radii, said Professor Tarduno.
He explained that one likely effect of this would have been the production of polar lights, or auroras, at much lower latitudes as many more solar particles breached the shield to collide with atmospheric molecules.
It probably also meant the atmosphere lost more of its lighter elements, like hydrogen, faster than had previously been supposed, argued Professor Tarduno.
The Barberton greenstone belt preserves some of the oldest rocks on the planet.
"What that means in an evolutionary sense to us - and this is just speculation but something we want to follow it up - is that perhaps this is suggesting the Earth was much more water-rich very early on," he said.
"If, even with this magnetic field, we are losing hydrogen and water, that would suggest the palaeo-Earth in its infant state must have had more water than we think about today."
Professor Tarduno’s team is now looking back still deeper into the past for evidence of a global magnetic field.
The field is generated by convection currents in the molten-iron outer-core of the planet, and finding evidence of an even more ancient field would say much about the interior state of the young Earth.
There are volcanic rocks in Africa, India and Australia that possibly retain a record that is 3.6bn years old.
"To go back even further in time, however, we don’t have the rocks available. But what we do have is certain younger sedimentary rocks that record minerals which were eroded from more ancient rocks - as old as four billion years old," Professor Tarduno told BBC News.
"We are developing techniques and we believe we can actually record the Earth’s magnetic field in these minerals also."
Article from: news.bbc.co.uk
2012: Leaks Found in Earth’s Magnetic Field
Video from: YouTube.com
Origin of Earth’s Magnetic Field
Video from: YouTube.com
Also tune into:
Walter Cruttenden - Lost Star of Myth and Time, Rise and Fall of Civilization and Consciousness
Walter Cruttenden - Sirius, The Binary Star & Precession
Rens van der Sluijs - Plasma Mythology & The Axis Mundi
Wallace Thornhill - The Electric Universe
William Henry - The Apotheosis is at Hand, NWO, COP15, Norway Blue Spiral & Stargates
Edmund Marriage - Global Catastrophe, Restart of Civilization & The Anu-Nagi (The Shining Ones)
Earth’s Magnetic Field - Wikipedia
Earth’s Magnetic Field Is 3.5 Billion Years Old
Intro to magnetic fields - What is the structure of the Earth’s magnetic field?
Magnetite - Wikipedia
Henges: Stonehenge, Woodhenge, Avebury & Stanton Drew (Video)
Moral judgments can be altered ... by magnets
Earth’s north magnetic pole racing towards Russia due to core flux
Nathan Stubblefield and Electromagnetism
Russians order Flight Changes, after Massive Magnetic Shift downs Airliners
Playing the Field: Geomagnetic Storms and the Stock Market
’Hidden Portal’ Concept Described: First Tunable Electromagnetic Gateway
Chris Dunn & Great Pyramid 3D Electromagnetic Power Plant Walkthrough (Video)
Oceans charge up new theory of magnetism
Mayan Calendar & Human DNA II - Prophesies & Sun Magnetic Reversals - part 1 (Video)
Sweet dreams are made of geomagnetic activity
Magnetic Portals Connect Sun and Earth
Phoenix Pole Shift
Latest News from our Front Page
Illegal Aliens Cleared For U.S. Military Service
2014 10 18
The Pentagon announced a new policy allowing illegal immigrants the opportunity to enlist in the armed forces, Thursday.
USA Today reports that the new recruitment policies will focus on people with "high-demand skills" like foreign language acumen and health care training:
"For the first time, the program — known as Military Accessions in the National Interest, or MAVNI — will ...
Bronze Age Sundial-Moondial Discovered in Russia
2014 10 16
A strange slab of rock discovered in Russia more than 20 years ago appears to be a combination sundial and moondial from the Bronze Age, a new study finds.
The slab is marked with round divots arranged in a circle, and an astronomical analysis suggests that these markings coincide with heavenly events, including sunrises and moonrises.
The sundial might be "evidence of ...
Humans may only survive 68 days on Mars
2014 10 15
Space enthusiasts planning a move to Mars may have to wait to relocate: conditions on the Red Planet are such that humans would likely begin dying within 68 days, a new study says.
Oxygen levels would start to deplete after about two months and scientists said new technologies are required before humans can permanently settle on Mars, according to the study ...
Tom Sunic’s letter to the US Ambassador to Hungary
2014 10 14
October 11, 2014
Mr. André Goodfriend
Embassy of the United States of America
Szabadság tér 12
Dear Mr. Goodfriend,
As an American citizen I would hereby like to express my concern over the recent decision by the Hungarian government to ban the National Policy Institute (NPI) conference which had been scheduled to take place in Budapest from October 3 to October 5, 2014. ...
"Vampire grave" found in Bulgaria
2014 10 14
A "vampire grave" containing a skeleton with a stake driven through its chest has been unearthed by a man known as "Bulgaria’s Indiana Jones".
Professor Nikolai Ovcharov – a crusading archaeologist who has dedicated his life to unearthing mysteries of ancient civilisations – said that he had made the discovery while excavating the ruins of Perperikon, an ancient Thracian city ...
|More News » |