Mysteries of glaciation
Hypothetical Center
In considering the merits of the theory that ice sheets came from glaciers formed on “centers,” let us create in our imagination an optimum of favorable hypothetical conditions under which mountain-type glaciers born on an “elevated center” could grow and creep outwardly and downwardly until they “coalesced” into a continental ice sheet, say, three thousand miles in diameter. Our ideal “center” of glacier accumulation will be like the ones others have visualized, except that ours is to be raised to a higher altitude.
We will first visualize a perfectly smooth symmetrical bowl, shaped like a saucer turned upside down and three thousand miles in diameter. We will place the dome at the “Laurentide center” in the Hudson Bay region of northeastern Canada. We will give it a liberal theoretical height, because we know the ice which is to form on it must travel a long way. Let us fix the height at 2% miles (13,200 feet), which is considerably greater than geologists believe the area had in the Pleistocene period. At this height the gradient down which the ice will have to flow from the top to a distance of fifteen hundred miles would be 1 to 600, which should be sufficient to sustain movement.
Now we shall imagine tremendously severe falls of snow concentrated over the center of the dome and enveloping a liberal area, say, five hundred miles in diameter. We shall assume that these snowfalls continue without a miss, all of every winter, from mid-September to mid-May, eight months of every year, for a thousand years. We shall assume that none of the snow and none of the ice subsequently formed from the snow, would melt during summer months, but that all of it would continue to accumulate and that the ice would creep radially outward and downward from the center until it formed an ice sheet three thousand miles in diameter, with an average depth of two thousand feet. It is thought that the Pleistocene ice sheet was at least that thick and probably thicker.
By simple mathematics we easily determine that over the “center,” five hundred miles in diameter, the depth of the average yearly accumulation of ice would have to be 72 feet. Seventy-two feet of ice is equivalent to at least 720 feet of snow. Hence, even with no allowance for summer melting, we see that tremendous snowfall, continued without pause for one thousand winters, would be required for ice to form on the above hypothetical “center” and “flow” outwardly in every direction until it formed an ice sheet covering an area equivalent to that which the Laurentide sheet is believed to have covered.
Spreading From Centers Questionable
It is impossible, for this writer at least, to accept the theory, even granting an optimum of favorable conditions, which we know did not exist. Extend the period of accumulation from one thousand years to twenty thousand, and the probability of concentrated snowfall on the center for that many successive winters would be even less. Shorten the period to five hundred years and the consequent required volume of annual snowfall would become more difficult to accept. Nor can the writer believe that the fantastic amount of water vapor required could be formed and raised to the skies in a climate so refrigerated that increments of winter snows would not melt in summers and so intemperate that ice could slowly “creep” southward, without melting, from northeastern Canada to southern Ohio, within forty degrees of the equator!
Furthermore, the reader san very easily demonstrate that ice flowing down the sides of a dome could never cover the whole surface. He need merely pour a soft batter over the center of a smooth bowl turned upside down. He will find that the liquid, thick or thin, will inevitably divide into separate streams which will never spread sidewise to cover the whole area as the “coalescent theory” predicates. In compliance with the greater pull of gravity, the streams will flow downward instead of sidewise. Furthermore, they lack the capacity to cover the entire surface of the dome by reason of the fact that as they flow outwardly the area to be covered constantly increases in proportion to the square of the increasing distance from center. If the streams cannot spread sidewise and completely cover a perfectly smooth, symmetrical dome, how can we believe that separate valley glaciers would spread sidewise on broken, irregular, uneven terrain, containing hills, valleys, canyons, lake basins, etc., and coalesce until they would form an unbroken blanket covering an area of millions of square miles?
Of course the ice in a continental ice sheet must have “flowed” to some extent wherever the ground under it sloped. It would be subject to the same gravital forces which cause mountain glaciers to flow. Also, on level ground and even on ground sloping moderately upward, the thickness or height of the ice would cause flow for a considerable distance back from the terminal edge. However, to believe that ice formed in the Hudson Bay region flowed southwestwardly for fifteen hundred miles to Cincinnati, uphill and downhill, across mountains, over cliffs and canyons, battling also fierce summer heat, just does not seem possible even by the wildest stretch of imagination.
A More Logical Source
Rather, does it not seem far more logical and probable that when ice covered all of Canada and the northern third of the United States, it came from snowfalls which embraced the entire area—snowfalls which, save for vastly greater magnitude and intensity, were precisely like snowfalls occurring in those areas today? Likewise, when glacial ice completely covered Mount Washington in New Hampshire, whose summit is 6,000 feet above sea level, it came from snow which fell upon the mountain just as it does today. The ice was not pushed up the mountain, over the top and down the other side, from a vague “center” of origin in Labrador, a thousand miles away, as the usual theory would have us believe.
Do not, therefore, logic and good sense urge upon us the conclusion that nothing less than an unearthly, extra-terrestrial fall of snow or ice could possibly have blanketed one-third of all land in both hemispheres at the same time, with ice hundreds, possibly thousands, of feet thick? The inconceivably vast quantity of moisture involved could not have been raised by solar heat, because the intensity of heat required would have prevented formation of snow and ice. On the other hand, had solar heat been so reduced that increments of earthly snows could have survived summer heat, water would not have evaporated in sufficient amount to form the snow.