Posts Tagged ‘ pole shift ’

Causes-Effects Pole Shift

ImageWell, science seems to be slowly agreeing on the fact that the earth’s magnetic north orientation has and is moving..

What will happen? What causes this?

Causes and effects

True polar wander can be caused by several mechanisms of redistributing mass and changing the moment of inertia tensor of the Earth:

  • Glacial cycles: redistribution of ice and water masses, and resultant deformation of the crust, changes the mass distribution around the Earth.
  • Perturbations of the topography of the core-mantle boundary, perhaps induced by differential core rotation and shift of its axial rotation vector, leading to CMB mass redistributions.
  • Mass redistributions in the mantle.

The orientation of the rotational axis itself could be changed by the high-velocity impact of a massive asteroid or comet.(Wiki)

 

Extinctions

Not long after the first geomagnetic polarity time scales were produced, scientists began exploring the possibility that reversals could be linked to extinctions. Most such proposals rest on the assumption that the Earth’s field has much lower intensity during reversals. Possibly the first such hypothesis was that high energy particles trapped in the Van Allen radiation belt could be liberated and bombard the Earth.

Detailed calculations confirm that, if the Earth’s dipole field disappeared entirely (leaving the quadrupole and higher components), most of the atmosphere could be reached by high energy particles. However, the atmosphere would stop them. Instead there would be secondary radiation of 10 Be or 36 Cl from collisions of cosmic rays with the atmosphere. There is evidence that this occurs both during secular variationand during reversals.

Another hypothesis by McCormac and Evans assumes that the Earth’s field would disappear entirely during reversals.

They argue that the atmosphere of Mars may have been eroded away by the solar wind because it had no magnetic field to protect it. They predict that ions would be stripped away from Earth’s atmosphere above 100 km. However, the evidence from paleointensity measurements is that the magnetic field does not disappear. Based on paleointensity data for the last 800,000 years, the magnetopause is still estimated to be at about 3 Earth radii during the Brunhes-Matuyama reversal.

Even if the magnetic field disappeared, the solar wind may induce a sufficient magnetic field in the Earth’s ionosphere to shield the surface from energetic particles.

Tests of correlations between extinctions and reversals are difficult for a number of reasons. Larger animals are too scarce in the fossil record for good statistics, so paleontologists have analyzed microfossil extinctions. Even microfossil data can be unreliable if there are hiatuses in the fossil record. It can appear that the extinction occurs at the end of a polarity interval when the rest of that polarity interval was simply eroded away.Statistical analysis shows no evidence for a correlation between reversals and extinctions.

Hypotheses have also been advanced linking reversals to mass extinctions.

Many such arguments were based on an apparent periodicity in the rate of reversals; more careful analyses show that the reversal record is not periodic.

It may be, however, that the ends of superchrons have caused vigorous convection leading to widespread volcanism, and that the subsequent airborne ash caused extinctions.

 

This all comes from studying past geologic records and fossil remains. How a subtle change will effect the environment and the planet is, at this moment, a best guess of anyone.

 

A magnetic reve…

A magnetic reversal in progress?

The South Atlantic Anomaly (SAA) is known to be growing in extent and spreading westwards from South Africa, as the Earth’s internal magnetic field rapidly weakens in this region. This may be early evidence of a forthcoming reversal in the direction of the Earth’s internal magnetic field. We do not know in detail precisely what occurs during such reversals, including the changes observed in the magnetic field and the time a reversal takes to complete. However these factors are important in knowing where the radiation risk may be increased and how the atmosphere might respond.

Earth’s magnetic field has had many highs, lows and reversals in its past. The last reversal was around 800,000 years ago. So the Earth is known to be able to re-generate its field and has done so during human pre-history. Understanding the development of the SAA may therefore be significant in understanding the reversal process and its impact on life and the natural environment.

Check it out.. This article comes from the National Geopraphic and that’s pretty ‘mainstream’.

New research shows the pole moving at rapid clip—25 miles (40 kilometers) a year.

 

 

Over the past century the pole has moved 685 miles (1,100 kilometers) from Arctic Canada toward Siberia, says Joe Stoner, a paleomagnetist at Oregon State University.

At its current rate the pole could move to Siberia within the next half-century, Stoner said.

“It’s moving really fast,” he said. “We’re seeing something that hasn’t happened for at least 500 years.”

Stoner presented his team’s research at the American Geophysical Union’s meeting last week in San Francisco.

Lorne McKee, a geomagnetic scientist at Natural Resources Canada, says that Stoner’s data fits his own readings.

“The movement of the pole definitely appears to be accelerating,” he said.

 

READ FULL ARTICLE HERE