The results came from a seabed sediment core collected by the U.S. Navy in the Antarctic Ross Sea in 1968 as part of Operation Deep Freeze. Samples from the core, covering almost 2.5 million years of the Earth's history, were stored at the Antarctic Marine Geology Research Facility in Tallahassee, Fla., before being re-discovered by Ken Verosub, professor of geology at UC Davis, who brought them back to Davis for magnetic analysis.
Exposed rock on land is weathered into fine grains that are washed out to sea and settle to the bottom. If the grains are magnetic, they will tend to align themselves with the Earth's magnetic field as they settle through the water column.
Verosub's lab uses highly sensitive equipment to measure the orientation of these magnetic grains in the sediments. That ancient magnetic record can be precisely dated by comparison to other rocks, and gives information about the behavior of the planet's magnetic field in the distant past.
"I think this is one of the best palaeomagnetic records yet from the Ross Sea," Verosub said.
Verosub, graduate student Luigi Jovane, postdoctoral researcher Gary Acton and Fabio Florindo at the National Institute for Geophysics and Vulcanology in Rome, Italy, found that there was more "scatter" in the magnetic directions than would be predicted, based on what is known about the Earth's magnetic field from cores collected closer to the equator.
But the results do compare well with recent computer simulations of fluid movement in the planet's core, which predict the existence of vortices in the magnetic field near the poles, Verosub said.
The paper is published online by the journal Earth and Planetary Science Letters, and will appear in the March 30 print edition of the journal.
Andy Fell | EurekAlert!
Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
15.11.2018 | Faculty of Science - University of Copenhagen
The unintended consequences of dams and reservoirs
14.11.2018 | Uppsala University
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences