The author, erstwhile glaciologist and at present a staff member of the Dept of Geological sciences, University of California (at Berkeley), is completely unknown to all in the closely related fields of science fiction and mystery story writing. On the other hand the list of scholarly papers which he has had published is too slight to be mentioned here. The editors take scant pleasure in presenting this article on the Ice Age and note apprehensively that the author has announced his intention of writing several similar articles for future issues.
Most people feel that an Ice Age is something they can just as well do without. If they are optimists they say they are happy not to be living in one, because if they were the weather would not be so nice as it is now and if they are pessimists they tell you that the Ice Age is coming back and that in a few years the weather will be even worse than it is now. Everyone except clothing manufacturers and furnace salesmen takes a dim view of an Ice Age. They think of it, if they bother to think of it at all, as a doleful time when it gets abominably cold and snows everlastingly and spoils their fun because they can't ask their friends if it is hot enough for them during the summer.
Surely this is a narrow view to take and those who take it are narrow people whose lives are filled with shallow everyday fictions. Wide people accept the wide view and their lives are filled with profound Sunday and Holiday fictions. Wide people are glum and unhappy because their wide view exposes the false glitter of superficiality, the ravelled scarf of euphemism, the twisted thread of promise, and other glum and unhappy aspects of LIFE in the raw. 1 Wide people with wide views understand the Ice Age because it was big and gloomy. For big, gloomy people it's a natural.
When we talk about the Ice Age we generally mean the most recent one-the Pleistocene Ice Age. It began about one million tears ago and has either not ended yet or just ended a few thousand years ago, depending on what Authority you talk to. The picture is somewhat confused because there were at least two earlier Ice Ages which usually aren't mentioned in polite conversation. They were rather peculiar. One occurred five or six or seven hundred million years ago near the end of the pre-Cambrian era or eon when the earth was populated only by algae, sponges, bar flies and other primitive, soft-shelled invertebrates. These pre-Cambrian glaciers seem to have moved in various directions across blistering deserts on all continents except South America and deposited tremendous thicknesses 2 of glacial till. Actually, since all of this happened so very long ago there is not much evidence of it left and we aren't even sure that all of the glaciers advanced at the same time. Some geologists think it simplifies matters to ignore the pre-Cambrian Ice Age altogether. Eight hundred feet of till in Australia is no skin off their noses.
The other earlier Ice Age occurred about two hundred million years ago during the Permian period when the amphibians were deciding whether or not to become reptiles. Some of them did and regretted it. This Ice Age affected all of the continents and seems to have been even more peculiar than the Pre-Cambrian one because the glaciers left even thicker deposits of till in some places 3 and were best developed near the equator. This strange behavior may be explained easily by the theory of continental drift 4 but most geologists don't like to explain it that way. They can't think of any other way to explain it so they just laugh it off. You can see why you don't hear much about these earlier Ice Ages.
Even the Pleistocene Ice Age is somewhat confusing because it consisted of four or five or six minor Ice Ages or advances of the great continental glaciers. These glaciers spread out in all directions from growth centers in Canada, Greenland, Scandinavia, Siberia, southern South America and Antarctica and seem to have grown and dwindled simultaneously in response to whatever climatic changes accelerated and retarded glaciation. A decade ago, glaciologists postulated five major advances of the glaciers but they now consider the next-to-last advance to have been a preliminary phase of the last advance. Most glaciologists just putter around changing earlier ideas and calling it scientific progress. Twenty years from now they will make science progress some more by declaring there were five major glacial advances. Glaciologists do not live in ivory towers because there is not enough ivory in the world to make a tower large enough for a glaciologist. They are all Big Men who like to spread themselves around. You get that way looking at Glaciers.
In North America the first advance of the Pleistocene glaciers ocurred about one million years ago and is called The Nebraskan because the deposits left by the ice are well preserved in Nebraska. The second advance of the ice ocurred about seven hundred and fifty thousand years ago and is called the Kansan because the glacial deposits are well developed in Kansas. The third advance is called the Illinoian and you should have a pretty good idea by now where its deposits are well preserved. It occurred about three hundred and fifty thousand years ago. The fourth advance is called the Wisconsin and, like the preceding three, consisted of a number of minor advances and retreats. The first minor advance of Wisconsin ice occurred one hundred to one hundred twenty thousand years ago and is called the Iowan. It is the one that used to be regarded as a separate major advance.
Geology textbooks tell you that the Wisconsin stage glaciers began to retreat twenty to twenty-five thousand years ago. This date was determined by guessing how long it has taken Niagara Falls to retreat nine miles up the Niagara river from the place where the falls started after the glaciers retreated and exposed the river's present course.
Recently, however, fragments of wood which were buried by deposits left by this last Wisconsin glacier have been dated by the radiocarbon method and found to be only ten to eleven thousand years old. This moves the Wisconsin stage up into fairly recent time and fouls up the previous interpretations of the so-called "Little Ice Age."
The "Little Ice Age" occurred about four thousand years ago and used to be regarded as a fifth (or sixth) glacial advance, even though it affected only mountain glaciers and was hardly worth bothering with at all. Glaciologists classified it as a separate advance rather than as a last gasp of the Wisconsin because it seemed to have appeared on the scene so long after the big Wisconsin glaciers had cashed in their chips and dried up.
This view was well advertised and the word spread that the Ice Age (Pleistocene epoch) had ended more than twenty thousand years ago when the Wisconsin glaciers vanished. Everything that had happened since that time, including the "Little Ice Age" was post-glacial (Recent epoch). Geologists believe this and printed it up in textbooks and by and by everybody thought the Ice Age was all washed up. Then the Carbon 14 determination showed that the late Wisconsin occurred ten rather than twenty thousand years ago and the whole thing came untangled.
Now, with only six instead of sixteen thousand years between the late Wisconsin retreat and the "Little Ice Age" advance, it looks as though the "Little Ice Age" was simply one of the closing phases of the dying Wisconsin glacial epoch and that the Pleistocene Ice Age may still be lurking around.
The next advance of the ice, if there is one, may not amount to much and you probably won't even notice it. At the very worst you might have to move south to Miami or Palm Springs but you can bet there will be a lot of glaciologists who won't notice it at all - they'll still be trying to decide whether or not there was a pre-Cambrian Ice Age.
1 If they notice the silver lining in every cloud they reflect that it is, after all, non-marketable.
2 More than eight hundred feet in central western Australia.
3 Two thousand feet in the southern Karoo district of Africa.
4 A theory, championed by the late Alfred Wegener and TIME magazine, which proposes that the continents float and drift about in the ocean basins.
Data entry and page scans provided by Judy Bemis
Data entry by Judy Bemis
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