Curt Sewell is the author of God at Ground Zero
CREATION BITS No 16.
How Was The Grand Canyon Formed? (Part 2)
| Author: Curt Sewell Subject: Creation Overviews Date: 11/8/1999 |
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Creation Bits No.15 introduced the question of “How was the Grand Canyon carved?” It gave a brief description of the canyon, and described four geological facts that must be addressed in finding an answer to that question. These are:
1) A tremendous amount of sediment was removed, and it isn’t obvious where that was deposited,
2) The canyon cuts directly through a huge uplifted region, the Kaibab Upwarp or Monocline,
3) Uniformitarian geologists consider that the monocline was lifted some 3000 feet, about 70 million years ago, whereas the Colorado River eroded the canyon between 50 and 70 million years ago, starting after the Colorado Plateau was in position, and
4) in recent times the Colorado River carries an average of about 168 million tons of sediment per year, mostly from its headlands region. It went on to describe the Antecedent River theory, which prevailed for over a century, but has now been discredited, even though it’s still presented in many textbooks.
In this paper, Creation Bits No.16, we’ll describe the other two possible theories that have been proposed, and will try to show that the most likely explanation strongly involves the reality of the Great Flood of Noah. The illustrations here are taken from Steven A. Austin’s book on the Grand Canyon,. Steven A. Austin, Grand Canyon: Monument to Catastrophe, (Institute for Creation Research, Santee, CA 92071, 1994), pp. 83-110. and the discussion is an abbreviation based on that book.
By about 1960, most geologists had abandoned the Antecedent River theory, but there was no obvious replacement. The “Stream Capture Theory,” nicknamed the “Precocious Gully Theory” was proposed, saying that most of the Canyon itself was carved by drainage of a gully, the Hualapai Drainage, running from the upper reaches of the Kaibab Plateau (see diagram (a) at right). This was said to have been in the Miocene epoch, some 10 million years ago. This gully supposedly kept eroding its upper end eastward, even though it was draining toward the west. Meanwhile, the upper Colorado River was thought to begin its flow in about its present position, except that instead of flowing west through what is now the Grand Canyon, it continued in a southeasterly direction along what is now the Little Colorado River, and finally joined either the Rio Grande or the Gila after going around east of the Kaibab Upwarp.
This theory says that the gully finally eroded its way east until it broke through the remaining part of the Kaibab Upwarp, at which point it “captured” the main part of the Colorado River (see diagram (b) at right), diverting its flow westward. In this way, it was thought that the gully could have carved most of the Grand Canyon in a relatively short time, alleviating the “missing sediment” problem, but raising several others.
The main problem is that it just doesn’t make sense. How could a gully behave in that way? There are no parallels in the entire world. There’s no east-west-trending fault in that area to define the course of a gully, and the present plateau surface has natural drainage to the south, not the west.
A number of sedimentary, basaltic, and volcanic ash deposits in various significant spots on these diagrams have been dated by potassium-argon methods. These have yielded dates ranging from about 2.4 to 10 million years, but they’re not in the right sequence to fit this Precocious Gully theory. Also a number of them are not consistent with each other. This leaves most geologists puzzled, and few are convinced that this theory is valid. Creationist geologists don’t worry about these, because they don’t consider radiogenic dates to be valid anyway, and they too are very doubtful about this theory. R.J. Rice summarized the quandary by saying:. R.J.Rice, “The Canyon Conundrum,” in Geographical Magazine 55, 1983, pg.291. This is cited by Austin in Grand Canyon, pg.107.
“After a century of study, we seem, if anything, to be further than ever from a full comprehension of how the Grand Canyon has evolved.”
The third theory to consider is the Breached Dam Theory. This is reasonable, it fits the evidences, and creationists believe it’s the true explanation for the origin of Grand Canyon. Most geologists reject it, however, because of its philosophical requirements — it implies massive catastrophism. This is actually the oldest of the various theories — it’s contained in the legends of the Havasupai Indians, who live today in villages within Grand Canyon. They say the Canyon formed just after the entire world was covered by a great flood. This is only one of over a hundred ancient world-wide-flood legends from many peoples.
This was brought up to date recently by creationist geologists. At right is a map of the entire Colorado Plateau region. The shaded area was produced by a computer, tracing out the 5700-foot contour lines. If the Grand Canyon were to be blocked today by a 5700-foot dam at its eastern end, this area would fill with water. It would cover some 30,000 square miles, and would contain 3,000 cubic miles of water — three times the volume of Lake Michigan. Austin and others propose that the eastern end of the Kaibab Upwarp was in position in the centuries following the Great Flood of Noah (described in Genesis 6-9), while much of the continent was still covered by water that hadn’t yet found its way to the ocean. Once an initial erosion began, from wave action, overtopping, piping, sapping, etc., catastrophic failure was inevitable.
Most geologists today agree that the Grand Coulee and the Washington scablands were formed in just this way, from the collapse of a post-Ice-Age glacial dam that released the waters of a 500-cubic-mile Lake Missoula in what is now Montana. This theory was first proposed by J.H. Bretz in 1923, but wasn’t accepted until the 1960’s.
Several traces of what are probably relict shorelines of these vast Colorado Plateau lakes have been found. Many fossils of fresh-water fish, amphibians, and beavers have been identified as ancient lake deposits. The heavily incised meanders of the San Juan River give evidence of a very heavy flow sometime in the past. So do the “alcove side canyons” throughout the Grand Canyon. So does the rythmite bedding of a turbidite delta at the tip of the Gulf of California. Work in this realm is continuing, but it appears likely that the true explanation for the carving of the Grand Canyon of Arizona will closely involve the restructuring of the earth following the Great Flood of Noah, as described in the Biblical book of Genesis.