This is 550 million years more seasoned than it was already accepted to be.
Researchers at Rochester College in New York investigated gems found in Western Australia.
Information on our planet's attractive field was observed to be protected in antiquated precious stones implanted in rock developments in the district.
The discoveries have been distributed in the diary Science.
As the Sun gradually loses mass, it transmits particles which can possibly disintegrate the World's environment. The attractive field shields Earth from these sunlight based winds.
The examination has surpassed the 2010 appraisal of 3.45 billion years.
"Seeing how the attractive field is produced is critical on the grounds that it's an essential property of the Earth. It separates it from different planets," Dr Jonathan Hill, from the School of Earth and Environment at the College of Leeds, disclosed to BBC News.
The World's attractive field is produced in light of the movement of liquid iron in its external center, alluded to as a geodynamo. To work, heat must be consistently discharged, which is supported by plate tectonics.
The group gathered rock tests from Jack Slopes in Western Australia, a zone that has been considered for a long time.
"The twist in iron molecules adjust in respect to the World's attractive field, and safeguard that data unless the material is warmed over a property called the Curie temperature," Teacher John Tarduno, a geophysicist at the College of Rochester and a main master on Earth's attractive field, told BBC News.
"For magnetite this is 580C. At the point when a mineral is warmed to over its Curie temperature, it loses that data."
A huge number of minor zircon gems were isolated by hand from the mass rock, as attractive partition systems would have polluted the examples.
An iron particle miniaturized scale test was utilized to focus the age of the zircon. It recognized lead and uranium, and radioactive rot empowered age determination.
The magnetisation was then decided with a magnetometer.
"It's a mechanical test to gauge the magnetisation of zircons so we manufactured an exceptional magnetometer for these studies," Prof Tarduno clarified, alluding to the SQID (superconducting quantum meddling gadget), which opens the attractive field record held in the zircons.
After the examination is done, just a couple percent of the information gathered breeze through the thorough unwavering quality tests, to guarantee the computed age is dependable.
"The occasion which shaped the Moon implies that we can never see what happened in the initial 100 million years of Earth's life as the data was wiped out by that occasion," Prof Tarduno said.
"To get more seasoned information, we should make sure that the zircons have been safeguarded and have not been warmed over their Curie temperature."
"Something that is imperative to build up for what's to come is whether the field has been consistently present for four billion years or on the off chance that it faded away and afterward another field returned," Dr Hill remarked.
The gathering is likewise chipping away at tests from Zimbabwe, which are thought to hold zircons with an age of 3.8 billion years of age.