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Canadian Discovery Takes Us Way Back

Canadian Discovery Takes Us Way Back


In science, the word “serendipity” refers to an unexpected, but happy discovery. Typically what is meant, is a discovery which was not sought but which leads to significant advances in knowledge or technology. Penicillin, for example was a serendipitous discovery by Sir Alexander Fleming in 1928. What he was trying to do, was grow cultures of common bacteria (germs). But what was that pesky mold doing growing in the culture? When Sir Alexander realized that the mold seemed to discourage the growth of the bacteria…. well the rest is history. However, I am not sure that the unlooked for discovery of gigantic sand waves in the Juan de Fuca Strait near Victoria, BC would qualify as serendipitous or not. While they seem to be the biggest and best sand waves known, scientists are apparently not curious enough to study the phenomenon further.

A news report in the National Post, June 13, 2001 p. A7 described the “mysterious formations” in which some of these sea bottom dunes approach heights of 25 metres — or about the height of a ten-story building. According to this news report, the principal investigators were oceanographer Richard Thomson of Canada’s Department of Fisheries and Oceans, and David Mosher, a marine geologist from the federal Bedford Institute of Oceanography in Dartmouth, Nova Scotia. These two scientists collaborated on a paper which they presented in France in the year 2000 at a conference on submarine sand waves and dunes. Apparently during unrelated research in 1996 which involved sonar and other imaging technology, Dr. Mosher discovered these amazing steeply sloped structures which apparently consist of coarse sand and fine gravel. In total these structures are estimated to comprise about 26 million cubic metres of sediment.

As far as the scientists involved are concerned, the origins of these underwater formations are mysterious. These men do not even know if they are the result of modern processes or relic conditions (something not duplicated at the present time). The sad thing is that this mystery may remain unresolved. Apparently no one has any plans to research the topic.

So why should we care about sand waves when the scientists involved are so casual about the whole topic? It so happens that sand wave studies shed some very interesting light on terrible flooding conditions of the past. Studies carried out in large flumes in science laboratories have indicated that sand waves form only under very deep and highly energetic water currents. The conditions under which the Juan de Fuca sand waves formed, for example, must have involved water depths of 125 m (about 400 ft) moving over sediments at approximately 170 cm/sec (6 feet/second). That is definitely not the case there now.

The really interesting feature of sand wave studies is the widespread occurrence of sedimentary rocks which must have been laid down from such rushing waters. Sandstones with cross bedded markings, for example, lie over huge tracts of the continent. Scientists used to attribute these cross bedded rocks to the action of wind. The only trouble with the idea of wind deposited sand however is that such dunes do not pile up on top of one another, as would be required for the deep deposits of such sandstone. One expert geologist for example remarked: “One must come to the conclusion therefore, that desert sediments in the form of sand-dunes are continuously on the move and do not usually accumulate for geologists of the future.” (Derek Ager. 1993. The New Catastrophism. Cambridge University Press p. 28)

Clearly such famous cross bedded sandstones as the Navajo sandstone (which reaches maximum thickness of about 700 m or 2200 ft at Zion National Park in Utah) cannot have come from wind deposited dunes. Studies conducted as early as 1975 (W. Freeman and G. Visher. Journal of Sedimentary Petrology 45: 651-668) have suggested alternatively that such sandstones were deposited, one layer after another on top of each other, from a violent sheet flow of sediment carried along by raging water currents. The scale of this flooding event appears all the more remarkable when we realize that the Navajo deposits cover parts of seven states in the American south west and involve 40,000 cubic kilometres of sand. Judging from the cross bedding pattern, the individual sand waves involved would have approached heights of 10 m (33 ft) and have been left behind from a water column of 54 m (180 ft) moving at 1.5 m/ second or 3-5 ft/second. There are many other cross bedded sandstone deposits such as the Coconino sandstone in the vicinity of the Grand Canyon. Here the sand waves may have approached 18 m (60 ft) tall, laid down from water almost 100 m deep and moving at bottom speeds of 160 cm (6 ft)/second.

Such calculations certainly cause one to reflect on the raging flood waters which left these tell tale traces. We can be grateful that the conditions which contribute to their formation are today found only in rare and restricted situations like San Francisco Bay where the tides move quickly through a narrow channel. Such flood waters over a continent however can only have spelled cataclysm!

So perhaps we can say that the Canadian findings of sand waves are indeed serendipitous. The agencies that fund such research and the local scientists just don’t realize it yet.

Margaret Helder
February 2002

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