The Long-Forgotten Science of Polar Wandering (cont.)
By Kyle Bennett
Way back in 1866, Evans
published a paper titled “On
a possible Geological Cause of Changes in the Position of the Axis of
the Earth’s Crust”
[ref].
This set out almost exactly the same theory
as Hapgood developed almost a century later.
Just like Hapgood, he believed the most
recent Ice Ages in Britain and North America could be explained by
crust displacements, claiming that these lands were much nearer the
North Pole in those times. A similar
paper was written by John Lubbock, titled “On Change of
Climate Resulting from a Change in the Earth’s Axis of
Rotation”, which was also presented to the Geological
Society.
Evans was convinced that evidence of extreme
climatic change found in the geological record, including fossils
proving that the Arctic was once tropical, could only be explained by
polar wandering, with displacements of the whole earth’s crust
being the suggested cause. As James Geikie described in
The Great Ice Age (1887):
“Mr Evans has ingeniously sought to account
for the remains of large trees that are found in Greenland, and for
the traces of glacial cold in this country [i.e. Britain], by
considering whether it might not be possible that the external crust
or shell of the globe had actually slid round its fluid or semi-fluid
nucleus, so as to bring the same areas of the external suface under
very different conditions. Thus it was suggested that lands, which at
one time basked under a tropical sun, might, in the slow course of
ages, be shifted to some more northern region, while countries which
had for long years been sealed up in the ice of the Arctic Circle
might eventually slide down into tropical latitudes.”
Evans came to this opinion after studying the work
of his colleague, Sir Henry James, who had also come to the
conclusion that the only possible explanation for those tropical
climates in the Arctic was polar wandering. As Evans explained in
1866:
“Sir Henry James….writing to the
Athenseum
newspaper in 1860, stated that he had long since arrived at the
conclusion that there was no possible explanation of some of the
geological phenomena testifying to the climate at certain spots
having greatly varied at different periods, without the supposition
of constant changes in the position of the axis of the earth’s
rotation.”
Evans was highly convinced by this view, and went
on to propose his theory of crust displacement, which would allow the
parts of the earth surface to back and forth between the tropical and
polar regions over the ages:
“this crust, from various causes, is liable
to changes disturbing its equilibrium, it becomes apparent that such
disturbances may lead, if not to a change in the position of the
general axis of the globe, yet at all events to a change in the
relative positions of the solid crust and the fluid nucleus, and in
consequence to a change in the axis of rotation, so far as the former
[the crust] is concerned.”
He proposed that rising mountain ranges may cause
a gravitational imbalance in the crust, which would then act to slide
the crust over the molten rock below, through the action of
centrifugal force upon them. He then discussed how large ice caps,
placed off-centre of the poles, would have a similar unbalancing
effect. So here was Hapgood’s theory
on the cause of Earth Crust Displacements, being seriously discussed
a century earlier by the President of the Geological Society. And the
arguments he used are still relevant today.
Evan even built a complicated model, with the
assistance of Francis Galton Darwin, which he presented to the
fellows of the Royal Society. It demonstrated, using weighted
adjustable screws attached to a wheel – representing a section
of the crust – how an imbalance in the spinning crust would
cause it to rotate. The subject was then seriously discussed a decade
later at a symposium of the Geological Society, on February 21st,
1877.
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