The Cataclysmic Pole Shift Hypothesis
Earth Changes and the Pole Shift
|The Cataclysmic Pole Shift Hypothesis
Earth Changes and the Pole Shift
The cataclysmic pole shift hypothesis suggests that there have been
geologically rapid shifts in the relative positions of the modern-day
geographic locations of the poles and the axis of rotation of the Earth,
creating calamities such as floods and tectonic events.
The cataclysmic pole shift hypothesis is the conjecture that there have
been rapid shifts in the relative positions of the modern-day geographic
locations of the poles and the axis of rotation of a planet.
The geographic poles of the Earth are the points on the surface of the
planet that are intersected by the axis of rotation.
The pole shift
hypothesis describes a change in location of these poles with respect to
the underlying surface – a phenomenon distinct from the changes in
axial orientation with respect to the plane of the ecliptic that are
caused by precession and nutation, and from true polar wander.
Pole shift hypotheses are not connected with plate tectonics, the
well-accepted geological theory that the Earth's surface consists of
solid plates which shift over a fluid asthenosphere; nor with
continental drift, the corollary to plate tectonics which maintains that
locations of the continents have moved slowly over the face of the
Earth, resulting in the gradual emerging and breakup of continents and
oceans over hundreds of millions of years.
Pole shift hypotheses are not the same as geomagnetic reversal, the
periodic reversal of the Earth's magnetic field (effectively switching
the north and south magnetic poles).
No form of the
hypothesis is accepted amongst the scientific community.
There is evidence of precession and changes in axial tilt, but this
change is on much longer time-scales and does not involve relative
motion of the spin axis with respect to the planet.
However, in what is
known as true polar wander, the solid Earth can rotate with respect to a
fixed spin axis. Research shows that during the last 200 million years a
total true polar wander of some 30° has occurred, but that no
super-rapid shifts in the Earth's pole were found during this period.
A characteristic rate of true polar wander is 1° per million years or
less. Between approximately 790 and 810 million years ago, when the
supercontinent Rodinia existed, two geologically-rapid phases of true
polar wander may have occurred. In each of these, the Earth rotated
It is now established that true polar wander has occurred at various
times in the past, but at rates of 1° per million years or less.
Analysis of the evidence does not lend credence to Hapgood's
hypothesized rapid displacement of layers of the Earth.
drastically overestimated the effects of changing mass distributions
across the Earth, calculations show that changing mass
distributions both on the surface and in the mantle can cause true polar
True polar wander, or the motion of the solid Earth with respect to a
fixed spin axis that causes the spin axis to lie over a new geographic
position, does occur. This is because of changes in mass distribution
throughout the Earth that modify its moment of inertia tensor.
consistently readjusts its orientation with respect to its spin axis
such that its spin axis is parallel to the axis about which it has its
greatest moment of inertia. This readjustment is very slow.
In 2001, historical evidence for true polar wander was found in
paleomagnetic data from granitic rocks from across North America. The
data from these rocks conflict with the hypothesis of a cataclysmic true
polar wander event.
This evidence indicated that the geographical poles
have not deviated by more than about 5° over the last 130 million
years. More rapid past possible occurrences of true polar wander have
been measured: from 790 to 810 million years ago, true polar wander of
approximately 55° may have occurred twice.
True polar wander can be caused by several mechanisms of redistributing
mass and changing the moment of inertia tensor of the Earth:
The orientation of the rotational
axis itself could be changed by high-velocity impact of a massive
asteroid or comet.
cycles: redistribution of ice and water masses, and resultant
deformation of the crust, changes the mass distribution around the
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.
redistributions in the mantle.