Jump to content

Talk:Coconino Sandstone/Archive 1

Page contents not supported in other languages.
From Wikipedia, the free encyclopedia
Archive 1

A local guidebook states that someone recently figured out that the Coconino Sandstone in the San Rafael Swell is really Cedar Mesa Sandstone of the Cutler Formation. I can't find a link that corroborates this. If it's true, we need to update this article, as the photo is of a river in the San Rafael Swell. Does anyone have a reference?

Creationist Geologists and Underwater Origin of Coconino Sandstone

I have to disagree with recent “POV” modifications by Goo2you. If he or any other person would take the time to review the current literature about the Coconino Sandstone, he or she would find that **currently** the only geologists and paleontologists, i.e. Dr. Brand, Dr. Chadwick, Dr. Andrew Snelling, and Dr. Steve Austin, who argue that the Coconino Sandstone was deposited underwater are either Old Earth or Young Earth creationists, who have a vested interest in using such arguments to explain the formation of the Coconino and similar sandstones in terms consistent with their personal religious beliefs. The statement that “Young and Old Earth creationists, i.e. Dr. Leonard Brand, have argued that fossil tracks in the Grand Canyon's Coconino Sandstone point to a more recent underwater deposition, rather than desert wind deposition of dry sand.” is not a point of view but at this time a fact that can be determined by comparing what is written about the Coconino Sandstone in any modern textbook on historical geology to what is written by creationist geologists.

Using identical criteria, it is true that one conventional geologist, Dr. Glenn Visher, back in the 1990’s argued that the Late Paleozoic Coconino Sandstone, and Mesozoic Navajo Sandstone, were both deposited underwater. However, his arguments have been so completely discredited that conventional, non-creationist, geologists, paleontologists, and other Earth scientists universally agree that sandstones such as the Coconino and Navajo sandstones are eolian in origin. In case of the Navajo Sandstone, a person need only look at the below publications to see how completely Dr. Glenn Visher’s arguments and evidence about an underwater origin for it have been demolished.

Reading the above papers, a person can see that the evidence and arguments used by Dr. Visher to argue for the underwater origin of the Coconino and Navajo sandstones have been completely discredited and are utterly meaningless. The only people, who take takes Dr. Visher’s arguments seriously anymore are either Old Earth or Young Earth creationists, who are desperate to find a conventional geologist, who supports their point of view.

Paul H. talk

Agreed; twice I removed a link to younger (flood) origin, when the Geology reference addresses only subaerial vs subaqueous and says nothing about the time of origin. I begin to think that this entire section is a violation of WP:UNDUE. Cheers Geologyguy (talk) 16:35, 13 December 2007 (UTC)

Cross-Bedding and Underwater Origin of Coconino Sandstone

Goo2you wrote in the section concerning Glen Visher arguments for the underwater origin of the Coconino Sandstone::

“Furthermore, there is other evidence that casts doubts on the view that the Coconino Sandstone cross beds formed in desert dunes. The average angle of slope of the Coconino cross beds is about 25° from the horizontal, less than the average angle of slope of sand beds within most modern desert sand dunes. Those sand beds slope at an angle of more than 25°, with some beds inclined as much as 30° to 34°, the angle of "rest" of dry sand. On the other hand, modern oceanic sand waves do not have "avalanche" faces of sand as common as desert dunes, and therefore, have lower average dips of cross beds.”

I have gone through pages 198-216 of “Chapter 5, Shelf Sedimentology” of Visher (1990), which is the alleged source of this argument for the underwater origin of the Coconino Sandstone. After carefully examining these pages several times, I found that Visher (1990) did not make this argument for the underwater origin of the Coconino Sandstone. He does not make any reference to the angle of cross-bedding when referring to the Coconino Sandstone. Because this argument is falsely presented as to its source and no primary source is given I have removed from it from the article. My best guess is that this argument comes not from a conventional geologist, i.e. Glenn Visher, but is parroted from a Young Earth creationist, i.e. Steve Austin, who has published similar scientifically problematic statements in articles, which he has written about the Coconino Sandstone and other aspects of Grand Canyon geology.

This argument engages in a fair amount of “knowledge filtering” as it selectively reports only the facts, which supports the underwater argument, from what is known about the angle of cross-bedding in eolian sands and sand waves. As discussed in Collinson and Thompson (1989), it is true that, for aeolian cross-beds, the large-scale dunes do have slip faces of 33 to 42 degrees. This argument ignores the fact that larger dunes have foresets dipping at 18 to 34 degrees as discussed in detail on pages 95-97 of Collinson and Thompson (1989). Thus, the dip of foreset cross-bedding, which are preferentially preserved in the rock record relative to the slip faces of eolian dunes as shown in Glennie (1970), is perfectly consistent with the average angle of dip found in the Coconino Sandstone cross-bedding. According to both Collinson and Thompson (1989) and Glennie (1970), the angle of eolian cross-bedding observed in modern dunes is consistent with the angle of eolian cross-bedding observed in the Coconino Sandstone. The scientific bankruptcy of this argument and the way it makes it conclusion by simply ignoring well established facts, which refute it, is another reason, for which it was removed.

Similarly, on page 161 of Prothero and Schwab (1996) states:

"The most characteristic feature of eolian dunes is their enormous cross-beds... Individual cross-bed sets can reach 30-35 m in thickness, with foresets that dip 20-35 degrees... Detailed studies of the faces of eolian dunes ... shows that the ripples move laterally across the face of the dune. This suggests that much of the cross-bed is formed not by sand avalanching down the face of the dune but by sand blown horizontally across its lee face."

References Cited

Collinson, J.D. and D.B. Thompson. 1989. Sedimentary Structures, 2nd ed, Unwin Hyman, London.

Glennie, K.S. 1970. Desert Sedimentary Environments, Developments in Sedimentology, vol. 14. Elsevier, Amsterdam and London

Prothero, D.R. and F. Schwab. 1996. Sedimentary Geology: An Introduction to Sedimentary Rocks and Stratigraphy. W.H. Freeman, New York.

Visher, G.S. 1990, Exploration Stratigraphy, 2dn ed. Penn Well Publishing, Tulsa, Okalahoma.

Note: I also looked at pages 166-168 of the 1st edition of "Exploration Stratigraphy" by Glenn Visher. It also lacked any mention of cross-bedding angles in the Coconino Sandstone. What it had to say about the Coconino Sandstone was the same as the 2nd edition.

Paul H. talk

On the contrary, the cross beds within the Coconino Sandstone (that is, the inclined beds of sand within the overall horizontal layer of sandstone) are excellent evidence that ocean currents moved the sand rapidly as dune-like mounds called sand waves.(See Amos & King, 1984.)

Schematic diagram showing the formation of cross beds during sand deposition by migration of underwater sand waves due to sustained water flow.

This diagram shows the way sand waves have been observed to produce cross beds in layers of sand. The water current moves over the sand surface building up mounds of sand. The current erodes sand from the "up-current" side of the sand wave and deposits it as inclined layers on the "down-current" side of the sand wave. Thus the sand wave moves in the direction of current flow as the inclined strata continue to be deposited on the down-current side of the sand wave. Continued erosion of sand by the current removes both the up-current side and top of the sand wave, the only part usually preserved being just the lower half of the down-current side. Thus the height of the cross beds preserved is just a fraction of the original sand wave height. Continued transportation of further sand will result in repeated layers containing inclined cross beds. These will be stacked up on each other.

Sand waves have been observed on certain parts of the ocean floor and in rivers, and have been produced in laboratory studies. Consequently, it has been demonstrated that the sand wave height is related to the water depth.(See Allen, 1970.) As the water depth increases so does the height of the sand waves which are produced. The heights of the sand waves are approximately one-fifth of the water depth. Similarly, the velocities of the water currents that produce sand waves have been determined.

Thus we have the means to calculate both the depth and velocity of the water responsible for transporting as sand waves the sand that now makes up the cross beds of the Coconino Sandstone. The thickest sets of cross beds in the Coconino Sandstone so far reported are 30 feet thick.(See Beus, 1979.) Cross beds of that height imply sand waves at least 60 feet high and a water depth of around 300 feet. For water that deep to make and move sand waves as high as 60 feet the minimum current velocity would need to be over 3 feet per second or 2 miles per hour. The maximum current velocity would have been almost 5.5 feet per second or 3.75 miles per hour. Beyond that velocity experimental and observational evidence has shown that flat sand beds only would be formed.

Now to have transported in such deep water the volume of sand that now makes up the Coconino Sandstone these current velocities would have to have been sustained in the one direction perhaps for days. Modern tides and normal ocean currents do not have these velocities in the open ocean, although deep-sea currents have been reported to attain velocities of between 50 cm and 250 cm per second through geographical restrictions. Thus catastrophic events provide the only mechanism, which can produce high velocity ocean currents over a wide area.

Hurricanes (or cyclones in the southern hemisphere) are thought to make modern sand waves of smaller size than those that have produced the cross beds in the Coconino Sandstone, but no measurements of hurricane driven currents approaching these velocities in deep water have been reported. The most severe modern ocean currents known have been generated during a tsunami or "tidal wave." In shallow oceans tsunami-induced currents have been reported on occasion to exceed 500 cm per second, and currents moving in the one direction have been sustained for hours.(See Coleman, 1978.) Such an event would be able to move large quantities of sand and, in its waning stages, build huge sand waves in deep water. Consequently, a tsunami provides the best modern analogy for understanding how large-scale cross beds such as those in the Coconino Sandstone could form.

The question then is what could deposit the Coconino Sandstone (and its equivalents), which covers an area of 200,000 square miles, averages 315 feet thick, and contains a volume of sand conservatively estimated at 10,000 cubic miles? And where could such an enormous quantity of sand come from? Cross beds within the Coconino dip consistently toward the south, indicating that the sand came from the north. However, along its northern occurrence, the Coconino rests directly on the Hermit Formation, which consists of siltstone and shale and so would not have been an ample source of sand of the type now found in the Coconino Sandstone. Consequently, this enormous volume of sand would have to have been transported a considerable distance, perhaps at least 200 or 300 miles. At the current velocities envisaged sand could be transported that distance in a matter of a few days.

Thus the evidence within the Coconino Sandstone does not support Paul's above-referenced geologists' interpretation of slow and gradual deposition of sand in a desert environment with dunes being climbed by wandering four-footed vertebrates. On the contrary, a careful examination of the evidence, backed up by experiments and observations of processes operating today, indicates catastrophic deposition of the sand by deep fast-moving water in a matter of days.

References cited

Amos, C.L. and King, E.L., 1984. "Bedforms of the Canadian eastern seaboard: a comparison with global occurrences." Marine Geology, vol. 57, pp. 167–208.

Allen, J.R.L., 1970. Physical Processes Sedimentation, George Allen and Unwin Ltd, London, p. 78.

Beus, S.S., 1979. "Trail log third day: South Kaibab Trail, Grand Canyon, Arizona." In: Carboniferous Stratigraphy in the Grand Canyon Country, Northern Arizona and Southern Nevada, S.S. Beus and R.R. Rawson (eds), American Geological Institute, Falls Church, Virginia, p. 16.

Coleman, P.J., 1978. "Tsunami sedimentation." In: The Encyclopedia of Sedimentology, R.W. Fairbridge and J. Bourgeois (eds), Dowden, Hutchinson and Ross, Stroudsburg, Pennsylvania, pp. 828–831.

Goo2you (talk) 05:11, 24 December 2007 (UTC)

Outdated "minority" view

Cut the long argumentative underwater origin stuff as outdated undue weight and basically creationist pov pushing. It was far too detailed for the article which should focus on physical features and geographic distribution and not delve into origin arguementation that is 15 - 20 years out of date. Vsmith (talk) 00:52, 28 December 2007 (UTC)

It was originally inserted as a simple well-supported encyclopedic addition, but someone else turned it into a long detailed thing. I recommend reverting to the original simple well-supported encyclopedic addition I did, if you really feel that way. --Goo2you (talk) 04:41, 28 December 2007 (UTC)
Your October edits more than doubled the article size. That was not a simple addition, but rather a heavy undue weight promotion of an outdated origin claim. Vsmith (talk) 05:19, 28 December 2007 (UTC)
I added two paragraphs in October. Paul H doubled the size with his POV rant. The current version includes a simple NPOV well-supported encyclopedic addition. Goo2you (talk) 15:30, 9 January 2008 (UTC)

<undent> The current version provides a balance meeting the requirements of NPOV: Giving "equal validity". More detail of the eolian origins would be welcome. .. dave souza, talk 21:13, 9 January 2008 (UTC)

Seems a bit unbalanced. The creationist view, which is based on a 1991 paper, is currently about 1/5 of the short article. That's a bit much for a thoroughly rejected view. I removed the supposed supporting ref of Glen Visher, as User:Paul H. noted the mis-quote above. Vsmith (talk) 00:16, 10 January 2008 (UTC)
Thanks for removing the dodgy quote. The creationist view section seems a reasonable size to me, but the main article is sadly lacking in explanations of the information supporting the æolian explanation. The TalkOrigins piece gives a concise description, and ir needed there are lots of sources above. To me, the aim would be to add a section explaining these principles, before the creationist bit.. .. dave souza, talk 01:23, 10 January 2008 (UTC)

The Visher ref should stand, even by your argumentation; User:Paul H. was only disputing its relation to a specific quote, not its (obvious) support of underwater deposition. His quote (see above): "it is true that one conventional geologist, Dr. Glenn Visher, back in the 1990’s argued that the Late Paleozoic Coconino Sandstone, and Mesozoic Navajo Sandstone, were both deposited underwater." Goo2you (talk) 05:16, 10 January 2008 (UTC)

This appears to give undue weight to an old and strongly disputed paper which has long been used as a creationist quote mine.[1][2] It's not even clear if it refers to the Cocinino, as creationists were using the argued marine origins of Navajo Sandstone to claim that it also applied to the Cocinino. This is OR based on a primary source, reliable secondary source needed. . . dave souza, talk 16:14, 10 January 2008 (UTC)
It's incorrect to remove primary source material that references exactly what is being discussed, and then demand a secondary source instead. No encyclopedia would accept that. Reference should obviously stay; Paul H. even acknowledges that Visher's research pointed to underwater deposition at Coconino. Goo2you (talk) 20:38, 10 January 2008 (UTC)

Paul H. has made it clear that Old and Young Earth Creationist are quote mining Visher's comments, which consist of a single paragraph and a couple of figures in a college textbook, on the Coconino Sandstone. Visher never did publish any detailed discussion of why he specifically interpreted the Coconino Sandstone to be marine in origin, and these interpretations have been discredited and abandoned by conventional geologists.[3] Goo2you, please make yourself better acquainted with WP:NOR, WP:NPOV and WP:NPOV/FAQ. I've argued for keeping a brief explanation of the creationist position in this article, but there's a strong case for leaving that extreme minority position amongst experts on the subject out altogether. .. dave souza, talk 17:30, 14 January 2008 (UTC)

Why is there a creationism reference?

Why is there a section devoted to a creationist explanation for the Coconino Sandstone? Creationism is nonsense. It makes about as much sense to have that section there as it does to have a section about flat earth theories in the article about the Earth. I don't care what trumped up evidence they have. All the creationist evidence is basically a biased interpretation of other evidence. I'm seriously considering removing the whole section. Dr. Morbius (talk) 03:07, 22 September 2009 (UTC)

Gone. WP:UNDUE Vsmith (talk) 03:25, 22 September 2009 (UTC)
Thank you. Dr. Morbius (talk) 20:16, 22 September 2009 (UTC)
Retrieved from "https://en.wikipedia.org/w/index.php?title=Talk:Coconino_Sandstone/Archive_1&oldid=922317933"