Monday, May 12, 2008

Dry Falls-Thinking Outside The Box




Ideas without precedent are generally looked upon with disfavor
and men are shocked if their conceptions of an orderly world are challenged.
Bretz, J Harlen 1928.





At the start of the new school term after the summer of 1960, we had a new geography teacher. Now if the truth be told, up until that time Geography was not up on the list of subjects even the diligent students found exciting. Geography often competed with Civics for the bottom honour of the least favoured subject.

Not any longer. We now had a bright young teacher straight from the University of Hong Kong; and from the first lesson we were spell bound. Yes, she was elegant and stylish, but I really did not think those were the only reasons for our newly discovered enthusiasm. She was able to capture our attention and made what we thought were boring subjects riveting. For the first time what happened millions of years ago fascinated us. Glaciers became hot.

Looking back now, I realise our understanding of Planet Earth was then in its infancy. Harry Hess of Princeton University was just formulating the Sea-Floor Spreading theory that is now generally accepted in the geological community.

We were so inspired that the Meteorology Club membership increased dramatically. A guided visit to the Royal Observatory (Hong Kong) further cemented our new found interest.

On my recent vacation in Washington State, I was reminded of our inspiring geography teacher. No, not many of us became geologists or meteorologists; but our interest in such matters stayed with us.

In Washington State we saw a geological puzzle that took over 40 years to solve: the Dry Falls.



The Dry Falls, Washington State, U.S.A.



The Dry Falls in northeast Washington was once the world’s largest waterfall, with water plunging 400 feet over a 3.5-mile-wide cataract. To put it into perspective, Victoria Falls, arguably the biggest and grandest fall in the world is only slightly over a mile wide and has a drop of 360 feet. Iguazu Falls is wider at 1.67 miles although nearly half a mile of it is now dry. Its drop ranges from 210 to 269 feet. Victoria Falls has therefore the largest curtain of water. Niagara, is small by comparison: ¾ mile wide and a drop of only 167 feet. However, it is the most easily accessible of the three falls.

The Dry Falls was the result of a series of events and catastrophes starting from 17 million years ago. For 6 million years, enormous lava flow after lava flow engulfed the area. This was followed by a warping of the plateau and an uplift of the mountainous region in the north. Then the Ice Age began about 1 million years ago, resulting in the formation of glaciers, subsequent flooding and formation of huge waterfalls. When the ice eventually receded, the network of rivers and streams in the plateau were left high and dry several hundred feet above the Columbia River. Today Dry Falls overlooks a desert oasis filled with lakes and abundant wildlife.

(Those interested in the full details can read the transcript of Mysteries of the Megaflood.)

The theory of the colossal flood was first proposed by geologist J. Harlen Bretz of the University of Chicago. In the summer of 1922, he became intrigued by the maze of huge streamless canyons, dry falls and other strange geological features in this area. As the area had few roads, he had to cover much of the 3000 square miles by foot. He worked painstakingly for the next seven summers, documenting what he saw, and came up with his hypothesis: a catastrophic flood greater than geologists had ever recognized on earth. It was a bold challenge to the prevailing principle of "uniformitarianism," which held that geological changes occur slowly, through steady processes. To other geologists, the idea of a sudden, colossal flood was unthinkable heresy. They emphatically declared his theory ‘wholly inadequate,’ ‘preposterous,’ and ‘incompetent.’ Though warned, Bretz proceeded to publish his conclusions.

In 1965, the International Geological Congress toured the Channeled Scablands (name invented by Bretz) and finally sent Bretz a telegram stating, ‘We are now all catastrophists.’

Satellite photographs taken in 1974 confirmed Bretz’s theory beyond doubt.

In 1979, the 96 year old Bretz was awarded the Penrose Medal of the Geological Society of America, that nation’s highest geologic honour.

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